diff --git a/wasm/src/in3.d.ts b/wasm/src/in3.d.ts
index b82556279..eda9ae8b0 100644
--- a/wasm/src/in3.d.ts
+++ b/wasm/src/in3.d.ts
@@ -37,6 +37,13 @@
  * All properties are optional and will be verified when sending the next request.
  */
 export declare interface IN3Config {
+    /**
+     * sets the transport-function.
+     * 
+     * @param fn the function to fetch the response for the given url
+     */
+    transport?: (url: string, payload: string, timeout?: number) => Promise<string>
+
     /**
      * if true the nodelist will be automaticly updated if the lastBlock is newer.
      * 
@@ -462,7 +469,7 @@ export default class IN3Generic<BigIntType, BufferType> {
 
 
     /**
-     * changes the transport-function.
+     * changes the default transport-function.
      * 
      * @param fn the function to fetch the response for the given url
      */
diff --git a/wasm/src/in3.js b/wasm/src/in3.js
index 1add858da..017f4aa4e 100644
--- a/wasm/src/in3.js
+++ b/wasm/src/in3.js
@@ -185,6 +185,10 @@ class IN3 {
         }
         this.needsSetConfig = !this.ptr
         if (this.ptr) {
+            if (this.config.transport) {
+                this.transport = this.config.transport
+                delete this.config.transport
+            }
             const r = in3w.ccall('in3_config', 'number', ['number', 'string'], [this.ptr, JSON.stringify(this.config)]);
             if (r) {
                 const ex = new Error(UTF8ToString(r))
@@ -361,7 +365,8 @@ function url_queue(req) {
     let counter = 0
     const promises = [], responses = []
     if (req.in3.config.debug) console.log("send req (" + req.ctx + ") to " + req.urls.join() + ' : ', JSON.stringify(req.payload, null, 2))
-    req.urls.forEach((url, i) => in3w.transport(url, JSON.stringify(req.payload), req.timeout || 30000).then(
+    const transport = req.in3.transport || in3w.transport
+    req.urls.forEach((url, i) => transport(url, JSON.stringify(req.payload), req.timeout || 30000).then(
         response => { responses.push({ i, url, response }); trigger() },
         error => { responses.push({ i, url, error }); trigger() }
     ))