diff --git a/README.md b/README.md
index 3e074c5..c002873 100755
--- a/README.md
+++ b/README.md
@@ -85,3 +85,6 @@ parser.on('error', error => { console.error(error) })
 parser.start()
 ```
 
+
+## Environment
+* `NODEWARC_WRITE_GZIPPED` - writes gzipped records to WARC outputs.
\ No newline at end of file
diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..6af1c38
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,1753 @@
+/** Declaration file generated by dts-gen */
+
+export = node_warc;
+
+declare class node_warc {
+    constructor(...args: any[]);
+
+    parseWARC(...args: any[]): void;
+
+    start(...args: any[]): void;
+
+    static prefixed: boolean;
+
+}
+
+declare namespace node_warc {
+    class ElectronRequestCap {
+        constructor(...args: any[]);
+
+        attach(...args: any[]): void;
+
+        maybeNetworkMessage(...args: any[]): void;
+
+        withNavigationManager(...args: any[]): void;
+
+    }
+
+    class ElectronWARCWriter {
+        constructor(...args: any[]);
+
+        generateWarcEntry(...args: any[]): void;
+
+        static prefixed: boolean;
+
+    }
+
+    class EventEmitter {
+        constructor();
+
+        addListener(event: any, fn: any, context: any): any;
+
+        emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+        eventNames(): any;
+
+        listenerCount(event: any): any;
+
+        listeners(event: any): any;
+
+        off(event: any, fn: any, context: any, once: any): any;
+
+        on(event: any, fn: any, context: any): any;
+
+        once(event: any, fn: any, context: any): any;
+
+        removeAllListeners(event: any): any;
+
+        removeListener(event: any, fn: any, context: any, once: any): any;
+
+        static EventEmitter: any;
+
+        static prefixed: boolean;
+
+    }
+
+    class PuppeteerRequestCap {
+        constructor(...args: any[]);
+
+        clear(...args: any[]): void;
+
+        iterateRequests(...args: any[]): any[];
+
+        requestWillBeSent(...args: any[]): void;
+
+        requests(...args: any[]): void;
+
+        startCapturing(...args: any[]): void;
+
+        stopCapturing(...args: any[]): void;
+
+    }
+
+    class PuppeteerWARCWriter extends WARCWriterBase {
+        constructor(...args: any[]);
+
+        generateWarcEntry(...args: any[]): void;
+
+        static prefixed: boolean;
+
+    }
+
+    class RemoteChromeRequestCap {
+        constructor(...args: any[]);
+
+        withNavigationManager(...args: any[]): void;
+
+    }
+
+    class RemoteChromeWARCWriter extends WARCWriterBase {
+        constructor(...args: any[]);
+
+        generateWarcEntry(...args: any[]): void;
+
+        static prefixed: boolean;
+
+    }
+
+    class WARCGzParser {
+        constructor(...args: any[]);
+
+        parseWARC(...args: any[]): void;
+
+        start(...args: any[]): void;
+
+        static prefixed: boolean;
+
+    }
+
+    class WARCParser {
+        constructor(...args: any[]);
+
+        parseWARC(...args: any[]): void;
+
+        start(...args: any[]): void;
+
+        static prefixed: boolean;
+
+    }
+
+    class WARCWriterBase {
+        constructor(...args: any[]);
+
+        end(...args: any[]): void;
+
+        initWARC(...args: any[]): void;
+
+        writeRecordBlock(...args: any[]): void;
+
+        writeRecordChunks(...args: any[]): void;
+
+        writeRequestRecord(...args: any[]): void;
+
+        writeResponseRecord(...args: any[]): void;
+
+        writeWarcInfoRecord(...args: any[]): void;
+
+        writeWarcMetadataOutlinks(...args: any[]): void;
+
+        static prefixed: boolean;
+
+    }
+
+    namespace ElectronRequestCap {
+        namespace prototype {
+            function attach(...args: any[]): void;
+
+            function clear(...args: any[]): void;
+
+            function entries(...args: any[]): void;
+
+            function forEach(...args: any[]): void;
+
+            function get(...args: any[]): void;
+
+            function has(...args: any[]): void;
+
+            function iterateRequests(...args: any[]): void;
+
+            function keys(...args: any[]): void;
+
+            function loadingFailed(...args: any[]): void;
+
+            function loadingFinished(...args: any[]): void;
+
+            function maybeNetworkMessage(...args: any[]): void;
+
+            function requestWillBeSent(...args: any[]): void;
+
+            function responseReceived(...args: any[]): void;
+
+            function size(...args: any[]): void;
+
+            function startCapturing(...args: any[]): void;
+
+            function stopCapturing(...args: any[]): void;
+
+            function values(...args: any[]): void;
+
+            function withNavigationManager(...args: any[]): void;
+
+            namespace iterateRequests {
+                namespace prototype {
+                    // Too-deep object hierarchy from node_warc.ElectronRequestCap.prototype.iterateRequests.prototype
+                    const next: any;
+
+                    // Too-deep object hierarchy from node_warc.ElectronRequestCap.prototype.iterateRequests.prototype
+                    const return: any;
+
+                    // Too-deep object hierarchy from node_warc.ElectronRequestCap.prototype.iterateRequests.prototype
+                    const throw: any;
+
+                }
+
+            }
+
+        }
+
+    }
+
+    namespace ElectronWARCWriter {
+        class EventEmitter {
+            constructor();
+
+            addListener(event: any, fn: any, context: any): any;
+
+            emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+            eventNames(): any;
+
+            listenerCount(event: any): any;
+
+            listeners(event: any): any;
+
+            off(event: any, fn: any, context: any, once: any): any;
+
+            on(event: any, fn: any, context: any): any;
+
+            once(event: any, fn: any, context: any): any;
+
+            removeAllListeners(event: any): any;
+
+            removeListener(event: any, fn: any, context: any, once: any): any;
+
+            static EventEmitter: any;
+
+            static prefixed: boolean;
+
+        }
+
+        namespace EventEmitter {
+            namespace prototype {
+                function addListener(event: any, fn: any, context: any): any;
+
+                function emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+                function eventNames(): any;
+
+                function listenerCount(event: any): any;
+
+                function listeners(event: any): any;
+
+                function off(event: any, fn: any, context: any, once: any): any;
+
+                function on(event: any, fn: any, context: any): any;
+
+                function once(event: any, fn: any, context: any): any;
+
+                function removeAllListeners(event: any): any;
+
+                function removeListener(event: any, fn: any, context: any, once: any): any;
+
+                namespace addListener {
+                    // Too-deep object hierarchy from node_warc.ElectronWARCWriter.EventEmitter.prototype.addListener
+                    const prototype: any;
+
+                }
+
+                namespace emit {
+                    // Too-deep object hierarchy from node_warc.ElectronWARCWriter.EventEmitter.prototype.emit
+                    const prototype: any;
+
+                }
+
+                namespace eventNames {
+                    // Too-deep object hierarchy from node_warc.ElectronWARCWriter.EventEmitter.prototype.eventNames
+                    const prototype: any;
+
+                }
+
+                namespace listenerCount {
+                    // Too-deep object hierarchy from node_warc.ElectronWARCWriter.EventEmitter.prototype.listenerCount
+                    const prototype: any;
+
+                }
+
+                namespace listeners {
+                    // Too-deep object hierarchy from node_warc.ElectronWARCWriter.EventEmitter.prototype.listeners
+                    const prototype: any;
+
+                }
+
+                namespace off {
+                    // Too-deep object hierarchy from node_warc.ElectronWARCWriter.EventEmitter.prototype.off
+                    const prototype: any;
+
+                }
+
+                namespace on {
+                    // Too-deep object hierarchy from node_warc.ElectronWARCWriter.EventEmitter.prototype.on
+                    const prototype: any;
+
+                }
+
+                namespace once {
+                    // Too-deep object hierarchy from node_warc.ElectronWARCWriter.EventEmitter.prototype.once
+                    const prototype: any;
+
+                }
+
+                namespace removeAllListeners {
+                    // Too-deep object hierarchy from node_warc.ElectronWARCWriter.EventEmitter.prototype.removeAllListeners
+                    const prototype: any;
+
+                }
+
+                namespace removeListener {
+                    // Too-deep object hierarchy from node_warc.ElectronWARCWriter.EventEmitter.prototype.removeListener
+                    const prototype: any;
+
+                }
+
+            }
+
+        }
+
+        namespace prototype {
+            function addListener(event: any, fn: any, context: any): any;
+
+            function emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+            function end(...args: any[]): void;
+
+            function eventNames(): any;
+
+            function generateWarcEntry(...args: any[]): void;
+
+            function initWARC(...args: any[]): void;
+
+            function listenerCount(event: any): any;
+
+            function listeners(event: any): any;
+
+            function off(event: any, fn: any, context: any, once: any): any;
+
+            function on(event: any, fn: any, context: any): any;
+
+            function once(event: any, fn: any, context: any): any;
+
+            function removeAllListeners(event: any): any;
+
+            function removeListener(event: any, fn: any, context: any, once: any): any;
+
+            function writeRecordBlock(...args: any[]): void;
+
+            function writeRecordChunks(...args: any[]): void;
+
+            function writeRequestRecord(...args: any[]): void;
+
+            function writeResponseRecord(...args: any[]): void;
+
+            function writeWarcInfoRecord(...args: any[]): void;
+
+            function writeWarcMetadataOutlinks(...args: any[]): void;
+
+            namespace addListener {
+                const prototype: {
+                };
+
+            }
+
+            namespace emit {
+                const prototype: {
+                };
+
+            }
+
+            namespace eventNames {
+                const prototype: {
+                };
+
+            }
+
+            namespace listenerCount {
+                const prototype: {
+                };
+
+            }
+
+            namespace listeners {
+                const prototype: {
+                };
+
+            }
+
+            namespace off {
+                const prototype: {
+                };
+
+            }
+
+            namespace on {
+                const prototype: {
+                };
+
+            }
+
+            namespace once {
+                const prototype: {
+                };
+
+            }
+
+            namespace removeAllListeners {
+                const prototype: {
+                };
+
+            }
+
+            namespace removeListener {
+                const prototype: {
+                };
+
+            }
+
+        }
+
+    }
+
+    namespace EventEmitter {
+        namespace prototype {
+            function addListener(event: any, fn: any, context: any): any;
+
+            function emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+            function eventNames(): any;
+
+            function listenerCount(event: any): any;
+
+            function listeners(event: any): any;
+
+            function off(event: any, fn: any, context: any, once: any): any;
+
+            function on(event: any, fn: any, context: any): any;
+
+            function once(event: any, fn: any, context: any): any;
+
+            function removeAllListeners(event: any): any;
+
+            function removeListener(event: any, fn: any, context: any, once: any): any;
+
+            namespace addListener {
+                const prototype: {
+                };
+
+            }
+
+            namespace emit {
+                const prototype: {
+                };
+
+            }
+
+            namespace eventNames {
+                const prototype: {
+                };
+
+            }
+
+            namespace listenerCount {
+                const prototype: {
+                };
+
+            }
+
+            namespace listeners {
+                const prototype: {
+                };
+
+            }
+
+            namespace off {
+                const prototype: {
+                };
+
+            }
+
+            namespace on {
+                const prototype: {
+                };
+
+            }
+
+            namespace once {
+                const prototype: {
+                };
+
+            }
+
+            namespace removeAllListeners {
+                const prototype: {
+                };
+
+            }
+
+            namespace removeListener {
+                const prototype: {
+                };
+
+            }
+
+        }
+
+    }
+
+    namespace PuppeteerRequestCap {
+        namespace prototype {
+            function clear(...args: any[]): void;
+
+            function iterateRequests(...args: any[]): void;
+
+            function requestWillBeSent(...args: any[]): void;
+
+            function requests(...args: any[]): void;
+
+            function startCapturing(...args: any[]): void;
+
+            function stopCapturing(...args: any[]): void;
+
+            namespace iterateRequests {
+                namespace prototype {
+                    // Too-deep object hierarchy from node_warc.PuppeteerRequestCap.prototype.iterateRequests.prototype
+                    const next: any;
+
+                    // Too-deep object hierarchy from node_warc.PuppeteerRequestCap.prototype.iterateRequests.prototype
+                    const return: any;
+
+                    // Too-deep object hierarchy from node_warc.PuppeteerRequestCap.prototype.iterateRequests.prototype
+                    const throw: any;
+
+                }
+
+            }
+
+        }
+
+    }
+
+    namespace PuppeteerWARCWriter {
+        class EventEmitter {
+            constructor();
+
+            addListener(event: any, fn: any, context: any): any;
+
+            emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+            eventNames(): any;
+
+            listenerCount(event: any): any;
+
+            listeners(event: any): any;
+
+            off(event: any, fn: any, context: any, once: any): any;
+
+            on(event: any, fn: any, context: any): any;
+
+            once(event: any, fn: any, context: any): any;
+
+            removeAllListeners(event: any): any;
+
+            removeListener(event: any, fn: any, context: any, once: any): any;
+
+            static EventEmitter: any;
+
+            static prefixed: boolean;
+
+        }
+
+        namespace EventEmitter {
+            namespace prototype {
+                function addListener(event: any, fn: any, context: any): any;
+
+                function emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+                function eventNames(): any;
+
+                function listenerCount(event: any): any;
+
+                function listeners(event: any): any;
+
+                function off(event: any, fn: any, context: any, once: any): any;
+
+                function on(event: any, fn: any, context: any): any;
+
+                function once(event: any, fn: any, context: any): any;
+
+                function removeAllListeners(event: any): any;
+
+                function removeListener(event: any, fn: any, context: any, once: any): any;
+
+                namespace addListener {
+                    // Too-deep object hierarchy from node_warc.PuppeteerWARCWriter.EventEmitter.prototype.addListener
+                    const prototype: any;
+
+                }
+
+                namespace emit {
+                    // Too-deep object hierarchy from node_warc.PuppeteerWARCWriter.EventEmitter.prototype.emit
+                    const prototype: any;
+
+                }
+
+                namespace eventNames {
+                    // Too-deep object hierarchy from node_warc.PuppeteerWARCWriter.EventEmitter.prototype.eventNames
+                    const prototype: any;
+
+                }
+
+                namespace listenerCount {
+                    // Too-deep object hierarchy from node_warc.PuppeteerWARCWriter.EventEmitter.prototype.listenerCount
+                    const prototype: any;
+
+                }
+
+                namespace listeners {
+                    // Too-deep object hierarchy from node_warc.PuppeteerWARCWriter.EventEmitter.prototype.listeners
+                    const prototype: any;
+
+                }
+
+                namespace off {
+                    // Too-deep object hierarchy from node_warc.PuppeteerWARCWriter.EventEmitter.prototype.off
+                    const prototype: any;
+
+                }
+
+                namespace on {
+                    // Too-deep object hierarchy from node_warc.PuppeteerWARCWriter.EventEmitter.prototype.on
+                    const prototype: any;
+
+                }
+
+                namespace once {
+                    // Too-deep object hierarchy from node_warc.PuppeteerWARCWriter.EventEmitter.prototype.once
+                    const prototype: any;
+
+                }
+
+                namespace removeAllListeners {
+                    // Too-deep object hierarchy from node_warc.PuppeteerWARCWriter.EventEmitter.prototype.removeAllListeners
+                    const prototype: any;
+
+                }
+
+                namespace removeListener {
+                    // Too-deep object hierarchy from node_warc.PuppeteerWARCWriter.EventEmitter.prototype.removeListener
+                    const prototype: any;
+
+                }
+
+            }
+
+        }
+
+        namespace prototype {
+            function addListener(event: any, fn: any, context: any): any;
+
+            function emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+            function end(...args: any[]): void;
+
+            function eventNames(): any;
+
+            function generateWarcEntry(...args: any[]): void;
+
+            function initWARC(...args: any[]): void;
+
+            function listenerCount(event: any): any;
+
+            function listeners(event: any): any;
+
+            function off(event: any, fn: any, context: any, once: any): any;
+
+            function on(event: any, fn: any, context: any): any;
+
+            function once(event: any, fn: any, context: any): any;
+
+            function removeAllListeners(event: any): any;
+
+            function removeListener(event: any, fn: any, context: any, once: any): any;
+
+            function writeRecordBlock(...args: any[]): void;
+
+            function writeRecordChunks(...args: any[]): void;
+
+            function writeRequestRecord(...args: any[]): void;
+
+            function writeResponseRecord(...args: any[]): void;
+
+            function writeWarcInfoRecord(...args: any[]): void;
+
+            function writeWarcMetadataOutlinks(...args: any[]): void;
+
+            namespace addListener {
+                const prototype: {
+                };
+
+            }
+
+            namespace emit {
+                const prototype: {
+                };
+
+            }
+
+            namespace eventNames {
+                const prototype: {
+                };
+
+            }
+
+            namespace listenerCount {
+                const prototype: {
+                };
+
+            }
+
+            namespace listeners {
+                const prototype: {
+                };
+
+            }
+
+            namespace off {
+                const prototype: {
+                };
+
+            }
+
+            namespace on {
+                const prototype: {
+                };
+
+            }
+
+            namespace once {
+                const prototype: {
+                };
+
+            }
+
+            namespace removeAllListeners {
+                const prototype: {
+                };
+
+            }
+
+            namespace removeListener {
+                const prototype: {
+                };
+
+            }
+
+        }
+
+    }
+
+    namespace RemoteChromeRequestCap {
+        namespace prototype {
+            function clear(...args: any[]): void;
+
+            function entries(...args: any[]): void;
+
+            function forEach(...args: any[]): void;
+
+            function get(...args: any[]): void;
+
+            function has(...args: any[]): void;
+
+            function iterateRequests(...args: any[]): void;
+
+            function keys(...args: any[]): void;
+
+            function loadingFailed(...args: any[]): void;
+
+            function loadingFinished(...args: any[]): void;
+
+            function requestWillBeSent(...args: any[]): void;
+
+            function responseReceived(...args: any[]): void;
+
+            function size(...args: any[]): void;
+
+            function startCapturing(...args: any[]): void;
+
+            function stopCapturing(...args: any[]): void;
+
+            function values(...args: any[]): void;
+
+            function withNavigationManager(...args: any[]): void;
+
+            namespace iterateRequests {
+                namespace prototype {
+                    // Too-deep object hierarchy from node_warc.RemoteChromeRequestCap.prototype.iterateRequests.prototype
+                    const next: any;
+
+                    // Too-deep object hierarchy from node_warc.RemoteChromeRequestCap.prototype.iterateRequests.prototype
+                    const return: any;
+
+                    // Too-deep object hierarchy from node_warc.RemoteChromeRequestCap.prototype.iterateRequests.prototype
+                    const throw: any;
+
+                }
+
+            }
+
+        }
+
+    }
+
+    namespace RemoteChromeWARCWriter {
+        class EventEmitter {
+            constructor();
+
+            addListener(event: any, fn: any, context: any): any;
+
+            emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+            eventNames(): any;
+
+            listenerCount(event: any): any;
+
+            listeners(event: any): any;
+
+            off(event: any, fn: any, context: any, once: any): any;
+
+            on(event: any, fn: any, context: any): any;
+
+            once(event: any, fn: any, context: any): any;
+
+            removeAllListeners(event: any): any;
+
+            removeListener(event: any, fn: any, context: any, once: any): any;
+
+            static EventEmitter: any;
+
+            static prefixed: boolean;
+
+        }
+
+        namespace EventEmitter {
+            namespace prototype {
+                function addListener(event: any, fn: any, context: any): any;
+
+                function emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+                function eventNames(): any;
+
+                function listenerCount(event: any): any;
+
+                function listeners(event: any): any;
+
+                function off(event: any, fn: any, context: any, once: any): any;
+
+                function on(event: any, fn: any, context: any): any;
+
+                function once(event: any, fn: any, context: any): any;
+
+                function removeAllListeners(event: any): any;
+
+                function removeListener(event: any, fn: any, context: any, once: any): any;
+
+                namespace addListener {
+                    // Too-deep object hierarchy from node_warc.RemoteChromeWARCWriter.EventEmitter.prototype.addListener
+                    const prototype: any;
+
+                }
+
+                namespace emit {
+                    // Too-deep object hierarchy from node_warc.RemoteChromeWARCWriter.EventEmitter.prototype.emit
+                    const prototype: any;
+
+                }
+
+                namespace eventNames {
+                    // Too-deep object hierarchy from node_warc.RemoteChromeWARCWriter.EventEmitter.prototype.eventNames
+                    const prototype: any;
+
+                }
+
+                namespace listenerCount {
+                    // Too-deep object hierarchy from node_warc.RemoteChromeWARCWriter.EventEmitter.prototype.listenerCount
+                    const prototype: any;
+
+                }
+
+                namespace listeners {
+                    // Too-deep object hierarchy from node_warc.RemoteChromeWARCWriter.EventEmitter.prototype.listeners
+                    const prototype: any;
+
+                }
+
+                namespace off {
+                    // Too-deep object hierarchy from node_warc.RemoteChromeWARCWriter.EventEmitter.prototype.off
+                    const prototype: any;
+
+                }
+
+                namespace on {
+                    // Too-deep object hierarchy from node_warc.RemoteChromeWARCWriter.EventEmitter.prototype.on
+                    const prototype: any;
+
+                }
+
+                namespace once {
+                    // Too-deep object hierarchy from node_warc.RemoteChromeWARCWriter.EventEmitter.prototype.once
+                    const prototype: any;
+
+                }
+
+                namespace removeAllListeners {
+                    // Too-deep object hierarchy from node_warc.RemoteChromeWARCWriter.EventEmitter.prototype.removeAllListeners
+                    const prototype: any;
+
+                }
+
+                namespace removeListener {
+                    // Too-deep object hierarchy from node_warc.RemoteChromeWARCWriter.EventEmitter.prototype.removeListener
+                    const prototype: any;
+
+                }
+
+            }
+
+        }
+
+        namespace prototype {
+            function addListener(event: any, fn: any, context: any): any;
+
+            function emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+            function end(...args: any[]): void;
+
+            function eventNames(): any;
+
+            function generateWarcEntry(...args: any[]): void;
+
+            function initWARC(...args: any[]): void;
+
+            function listenerCount(event: any): any;
+
+            function listeners(event: any): any;
+
+            function off(event: any, fn: any, context: any, once: any): any;
+
+            function on(event: any, fn: any, context: any): any;
+
+            function once(event: any, fn: any, context: any): any;
+
+            function removeAllListeners(event: any): any;
+
+            function removeListener(event: any, fn: any, context: any, once: any): any;
+
+            function writeRecordBlock(...args: any[]): void;
+
+            function writeRecordChunks(...args: any[]): void;
+
+            function writeRequestRecord(...args: any[]): void;
+
+            function writeResponseRecord(...args: any[]): void;
+
+            function writeWarcInfoRecord(...args: any[]): void;
+
+            function writeWarcMetadataOutlinks(...args: any[]): void;
+
+            namespace addListener {
+                const prototype: {
+                };
+
+            }
+
+            namespace emit {
+                const prototype: {
+                };
+
+            }
+
+            namespace eventNames {
+                const prototype: {
+                };
+
+            }
+
+            namespace listenerCount {
+                const prototype: {
+                };
+
+            }
+
+            namespace listeners {
+                const prototype: {
+                };
+
+            }
+
+            namespace off {
+                const prototype: {
+                };
+
+            }
+
+            namespace on {
+                const prototype: {
+                };
+
+            }
+
+            namespace once {
+                const prototype: {
+                };
+
+            }
+
+            namespace removeAllListeners {
+                const prototype: {
+                };
+
+            }
+
+            namespace removeListener {
+                const prototype: {
+                };
+
+            }
+
+        }
+
+    }
+
+    namespace WARCGzParser {
+        class EventEmitter {
+            constructor();
+
+            addListener(event: any, fn: any, context: any): any;
+
+            emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+            eventNames(): any;
+
+            listenerCount(event: any): any;
+
+            listeners(event: any): any;
+
+            off(event: any, fn: any, context: any, once: any): any;
+
+            on(event: any, fn: any, context: any): any;
+
+            once(event: any, fn: any, context: any): any;
+
+            removeAllListeners(event: any): any;
+
+            removeListener(event: any, fn: any, context: any, once: any): any;
+
+            static EventEmitter: any;
+
+            static prefixed: boolean;
+
+        }
+
+        namespace EventEmitter {
+            namespace prototype {
+                function addListener(event: any, fn: any, context: any): any;
+
+                function emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+                function eventNames(): any;
+
+                function listenerCount(event: any): any;
+
+                function listeners(event: any): any;
+
+                function off(event: any, fn: any, context: any, once: any): any;
+
+                function on(event: any, fn: any, context: any): any;
+
+                function once(event: any, fn: any, context: any): any;
+
+                function removeAllListeners(event: any): any;
+
+                function removeListener(event: any, fn: any, context: any, once: any): any;
+
+                namespace addListener {
+                    // Too-deep object hierarchy from node_warc.WARCGzParser.EventEmitter.prototype.addListener
+                    const prototype: any;
+
+                }
+
+                namespace emit {
+                    // Too-deep object hierarchy from node_warc.WARCGzParser.EventEmitter.prototype.emit
+                    const prototype: any;
+
+                }
+
+                namespace eventNames {
+                    // Too-deep object hierarchy from node_warc.WARCGzParser.EventEmitter.prototype.eventNames
+                    const prototype: any;
+
+                }
+
+                namespace listenerCount {
+                    // Too-deep object hierarchy from node_warc.WARCGzParser.EventEmitter.prototype.listenerCount
+                    const prototype: any;
+
+                }
+
+                namespace listeners {
+                    // Too-deep object hierarchy from node_warc.WARCGzParser.EventEmitter.prototype.listeners
+                    const prototype: any;
+
+                }
+
+                namespace off {
+                    // Too-deep object hierarchy from node_warc.WARCGzParser.EventEmitter.prototype.off
+                    const prototype: any;
+
+                }
+
+                namespace on {
+                    // Too-deep object hierarchy from node_warc.WARCGzParser.EventEmitter.prototype.on
+                    const prototype: any;
+
+                }
+
+                namespace once {
+                    // Too-deep object hierarchy from node_warc.WARCGzParser.EventEmitter.prototype.once
+                    const prototype: any;
+
+                }
+
+                namespace removeAllListeners {
+                    // Too-deep object hierarchy from node_warc.WARCGzParser.EventEmitter.prototype.removeAllListeners
+                    const prototype: any;
+
+                }
+
+                namespace removeListener {
+                    // Too-deep object hierarchy from node_warc.WARCGzParser.EventEmitter.prototype.removeListener
+                    const prototype: any;
+
+                }
+
+            }
+
+        }
+
+        namespace prototype {
+            function addListener(event: any, fn: any, context: any): any;
+
+            function emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+            function eventNames(): any;
+
+            function listenerCount(event: any): any;
+
+            function listeners(event: any): any;
+
+            function off(event: any, fn: any, context: any, once: any): any;
+
+            function on(event: any, fn: any, context: any): any;
+
+            function once(event: any, fn: any, context: any): any;
+
+            function parseWARC(...args: any[]): void;
+
+            function removeAllListeners(event: any): any;
+
+            function removeListener(event: any, fn: any, context: any, once: any): any;
+
+            function start(...args: any[]): void;
+
+            namespace addListener {
+                const prototype: {
+                };
+
+            }
+
+            namespace emit {
+                const prototype: {
+                };
+
+            }
+
+            namespace eventNames {
+                const prototype: {
+                };
+
+            }
+
+            namespace listenerCount {
+                const prototype: {
+                };
+
+            }
+
+            namespace listeners {
+                const prototype: {
+                };
+
+            }
+
+            namespace off {
+                const prototype: {
+                };
+
+            }
+
+            namespace on {
+                const prototype: {
+                };
+
+            }
+
+            namespace once {
+                const prototype: {
+                };
+
+            }
+
+            namespace removeAllListeners {
+                const prototype: {
+                };
+
+            }
+
+            namespace removeListener {
+                const prototype: {
+                };
+
+            }
+
+        }
+
+    }
+
+    namespace WARCParser {
+        class EventEmitter {
+            constructor();
+
+            addListener(event: any, fn: any, context: any): any;
+
+            emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+            eventNames(): any;
+
+            listenerCount(event: any): any;
+
+            listeners(event: any): any;
+
+            off(event: any, fn: any, context: any, once: any): any;
+
+            on(event: any, fn: any, context: any): any;
+
+            once(event: any, fn: any, context: any): any;
+
+            removeAllListeners(event: any): any;
+
+            removeListener(event: any, fn: any, context: any, once: any): any;
+
+            static EventEmitter: any;
+
+            static prefixed: boolean;
+
+        }
+
+        namespace EventEmitter {
+            namespace prototype {
+                function addListener(event: any, fn: any, context: any): any;
+
+                function emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+                function eventNames(): any;
+
+                function listenerCount(event: any): any;
+
+                function listeners(event: any): any;
+
+                function off(event: any, fn: any, context: any, once: any): any;
+
+                function on(event: any, fn: any, context: any): any;
+
+                function once(event: any, fn: any, context: any): any;
+
+                function removeAllListeners(event: any): any;
+
+                function removeListener(event: any, fn: any, context: any, once: any): any;
+
+                namespace addListener {
+                    // Too-deep object hierarchy from node_warc.WARCParser.EventEmitter.prototype.addListener
+                    const prototype: any;
+
+                }
+
+                namespace emit {
+                    // Too-deep object hierarchy from node_warc.WARCParser.EventEmitter.prototype.emit
+                    const prototype: any;
+
+                }
+
+                namespace eventNames {
+                    // Too-deep object hierarchy from node_warc.WARCParser.EventEmitter.prototype.eventNames
+                    const prototype: any;
+
+                }
+
+                namespace listenerCount {
+                    // Too-deep object hierarchy from node_warc.WARCParser.EventEmitter.prototype.listenerCount
+                    const prototype: any;
+
+                }
+
+                namespace listeners {
+                    // Too-deep object hierarchy from node_warc.WARCParser.EventEmitter.prototype.listeners
+                    const prototype: any;
+
+                }
+
+                namespace off {
+                    // Too-deep object hierarchy from node_warc.WARCParser.EventEmitter.prototype.off
+                    const prototype: any;
+
+                }
+
+                namespace on {
+                    // Too-deep object hierarchy from node_warc.WARCParser.EventEmitter.prototype.on
+                    const prototype: any;
+
+                }
+
+                namespace once {
+                    // Too-deep object hierarchy from node_warc.WARCParser.EventEmitter.prototype.once
+                    const prototype: any;
+
+                }
+
+                namespace removeAllListeners {
+                    // Too-deep object hierarchy from node_warc.WARCParser.EventEmitter.prototype.removeAllListeners
+                    const prototype: any;
+
+                }
+
+                namespace removeListener {
+                    // Too-deep object hierarchy from node_warc.WARCParser.EventEmitter.prototype.removeListener
+                    const prototype: any;
+
+                }
+
+            }
+
+        }
+
+        namespace prototype {
+            function addListener(event: any, fn: any, context: any): any;
+
+            function emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+            function eventNames(): any;
+
+            function listenerCount(event: any): any;
+
+            function listeners(event: any): any;
+
+            function off(event: any, fn: any, context: any, once: any): any;
+
+            function on(event: any, fn: any, context: any): any;
+
+            function once(event: any, fn: any, context: any): any;
+
+            function parseWARC(...args: any[]): void;
+
+            function removeAllListeners(event: any): any;
+
+            function removeListener(event: any, fn: any, context: any, once: any): any;
+
+            function start(...args: any[]): void;
+
+            namespace addListener {
+                const prototype: {
+                };
+
+            }
+
+            namespace emit {
+                const prototype: {
+                };
+
+            }
+
+            namespace eventNames {
+                const prototype: {
+                };
+
+            }
+
+            namespace listenerCount {
+                const prototype: {
+                };
+
+            }
+
+            namespace listeners {
+                const prototype: {
+                };
+
+            }
+
+            namespace off {
+                const prototype: {
+                };
+
+            }
+
+            namespace on {
+                const prototype: {
+                };
+
+            }
+
+            namespace once {
+                const prototype: {
+                };
+
+            }
+
+            namespace removeAllListeners {
+                const prototype: {
+                };
+
+            }
+
+            namespace removeListener {
+                const prototype: {
+                };
+
+            }
+
+        }
+
+    }
+
+    namespace WARCWriterBase {
+        class EventEmitter {
+            constructor();
+
+            addListener(event: any, fn: any, context: any): any;
+
+            emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+            eventNames(): any;
+
+            listenerCount(event: any): any;
+
+            listeners(event: any): any;
+
+            off(event: any, fn: any, context: any, once: any): any;
+
+            on(event: any, fn: any, context: any): any;
+
+            once(event: any, fn: any, context: any): any;
+
+            removeAllListeners(event: any): any;
+
+            removeListener(event: any, fn: any, context: any, once: any): any;
+
+            static EventEmitter: any;
+
+            static prefixed: boolean;
+
+        }
+
+        namespace EventEmitter {
+            namespace prototype {
+                function addListener(event: any, fn: any, context: any): any;
+
+                function emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+                function eventNames(): any;
+
+                function listenerCount(event: any): any;
+
+                function listeners(event: any): any;
+
+                function off(event: any, fn: any, context: any, once: any): any;
+
+                function on(event: any, fn: any, context: any): any;
+
+                function once(event: any, fn: any, context: any): any;
+
+                function removeAllListeners(event: any): any;
+
+                function removeListener(event: any, fn: any, context: any, once: any): any;
+
+                namespace addListener {
+                    // Too-deep object hierarchy from node_warc.WARCWriterBase.EventEmitter.prototype.addListener
+                    const prototype: any;
+
+                }
+
+                namespace emit {
+                    // Too-deep object hierarchy from node_warc.WARCWriterBase.EventEmitter.prototype.emit
+                    const prototype: any;
+
+                }
+
+                namespace eventNames {
+                    // Too-deep object hierarchy from node_warc.WARCWriterBase.EventEmitter.prototype.eventNames
+                    const prototype: any;
+
+                }
+
+                namespace listenerCount {
+                    // Too-deep object hierarchy from node_warc.WARCWriterBase.EventEmitter.prototype.listenerCount
+                    const prototype: any;
+
+                }
+
+                namespace listeners {
+                    // Too-deep object hierarchy from node_warc.WARCWriterBase.EventEmitter.prototype.listeners
+                    const prototype: any;
+
+                }
+
+                namespace off {
+                    // Too-deep object hierarchy from node_warc.WARCWriterBase.EventEmitter.prototype.off
+                    const prototype: any;
+
+                }
+
+                namespace on {
+                    // Too-deep object hierarchy from node_warc.WARCWriterBase.EventEmitter.prototype.on
+                    const prototype: any;
+
+                }
+
+                namespace once {
+                    // Too-deep object hierarchy from node_warc.WARCWriterBase.EventEmitter.prototype.once
+                    const prototype: any;
+
+                }
+
+                namespace removeAllListeners {
+                    // Too-deep object hierarchy from node_warc.WARCWriterBase.EventEmitter.prototype.removeAllListeners
+                    const prototype: any;
+
+                }
+
+                namespace removeListener {
+                    // Too-deep object hierarchy from node_warc.WARCWriterBase.EventEmitter.prototype.removeListener
+                    const prototype: any;
+
+                }
+
+            }
+
+        }
+
+        namespace prototype {
+            function addListener(event: any, fn: any, context: any): any;
+
+            function emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+            function end(...args: any[]): void;
+
+            function eventNames(): any;
+
+            function initWARC(...args: any[]): void;
+
+            function listenerCount(event: any): any;
+
+            function listeners(event: any): any;
+
+            function off(event: any, fn: any, context: any, once: any): any;
+
+            function on(event: any, fn: any, context: any): any;
+
+            function once(event: any, fn: any, context: any): any;
+
+            function removeAllListeners(event: any): any;
+
+            function removeListener(event: any, fn: any, context: any, once: any): any;
+
+            function writeRecordBlock(...args: any[]): void;
+
+            function writeRecordChunks(...args: any[]): void;
+
+            function writeRequestRecord(...args: any[]): void;
+
+            function writeResponseRecord(...args: any[]): void;
+
+            function writeWarcInfoRecord(...args: any[]): void;
+
+            function writeWarcMetadataOutlinks(...args: any[]): void;
+
+            namespace addListener {
+                const prototype: {
+                };
+
+            }
+
+            namespace emit {
+                const prototype: {
+                };
+
+            }
+
+            namespace eventNames {
+                const prototype: {
+                };
+
+            }
+
+            namespace listenerCount {
+                const prototype: {
+                };
+
+            }
+
+            namespace listeners {
+                const prototype: {
+                };
+
+            }
+
+            namespace off {
+                const prototype: {
+                };
+
+            }
+
+            namespace on {
+                const prototype: {
+                };
+
+            }
+
+            namespace once {
+                const prototype: {
+                };
+
+            }
+
+            namespace removeAllListeners {
+                const prototype: {
+                };
+
+            }
+
+            namespace removeListener {
+                const prototype: {
+                };
+
+            }
+
+        }
+
+    }
+
+    namespace prototype {
+        function addListener(event: any, fn: any, context: any): any;
+
+        function emit(event: any, a1: any, a2: any, a3: any, a4: any, a5: any, ...args: any[]): any;
+
+        function eventNames(): any;
+
+        function listenerCount(event: any): any;
+
+        function listeners(event: any): any;
+
+        function off(event: any, fn: any, context: any, once: any): any;
+
+        function on(event: any, fn: any, context: any): any;
+
+        function once(event: any, fn: any, context: any): any;
+
+        function parseWARC(...args: any[]): void;
+
+        function removeAllListeners(event: any): any;
+
+        function removeListener(event: any, fn: any, context: any, once: any): any;
+
+        function start(...args: any[]): void;
+
+        namespace addListener {
+            const prototype: {
+            };
+
+        }
+
+        namespace emit {
+            const prototype: {
+            };
+
+        }
+
+        namespace eventNames {
+            const prototype: {
+            };
+
+        }
+
+        namespace listenerCount {
+            const prototype: {
+            };
+
+        }
+
+        namespace listeners {
+            const prototype: {
+            };
+
+        }
+
+        namespace off {
+            const prototype: {
+            };
+
+        }
+
+        namespace on {
+            const prototype: {
+            };
+
+        }
+
+        namespace once {
+            const prototype: {
+            };
+
+        }
+
+        namespace removeAllListeners {
+            const prototype: {
+            };
+
+        }
+
+        namespace removeListener {
+            const prototype: {
+            };
+
+        }
+
+    }
+
+}
diff --git a/lib/writers/warcWriterBase.js b/lib/writers/warcWriterBase.js
index a470588..6395efc 100755
--- a/lib/writers/warcWriterBase.js
+++ b/lib/writers/warcWriterBase.js
@@ -1,4 +1,7 @@
 const fs = require('fs-extra')
+/** @ignore */
+const zlib = require('zlib');
+/** @ignore */
 const Path = require('path')
 const uuid = require('uuid/v1')
 const EventEmitter = require('eventemitter3')
@@ -245,6 +248,11 @@ class WARCWriterBase extends EventEmitter {
    */
   writeRecordBlock (recordBuffer) {
     return new Promise((resolve, reject) => {
+      if (process.env.NODEWARC_WRITE_GZIPPED) {
+        // we're in gzipped mode - GZip the buffer
+        recordBuffer = zlib.gzipSync(recordBuffer)
+      }
+
       if (!this._warcOutStream.write(recordBuffer, 'utf8')) {
         this._warcOutStream.once('drain', resolve)
       } else {