diff --git a/packages/cli/cli.conversions.test.js b/packages/cli/cli.conversions.test.js
index dfcc4b3c2..271882d74 100644
--- a/packages/cli/cli.conversions.test.js
+++ b/packages/cli/cli.conversions.test.js
@@ -8,19 +8,23 @@ test.afterEach.always((t) => {
   // remove files
   try {
     if (t.context.file1Path) fs.unlinkSync(t.context.file1Path)
-  } catch (err) {}
+  } catch (err) { }
 
   try {
     if (t.context.file2Path) fs.unlinkSync(t.context.file2Path)
-  } catch (err) {}
+  } catch (err) { }
 
   try {
     if (t.context.file3Path) fs.unlinkSync(t.context.file3Path)
-  } catch (err) {}
+  } catch (err) { }
 
   try {
     if (t.context.file4Path) fs.unlinkSync(t.context.file4Path)
-  } catch (err) {}
+  } catch (err) { }
+
+  try {
+    if (t.context.file5Path) fs.unlinkSync(t.context.file5Path)
+  } catch (err) { }
 })
 
 test.beforeEach((t) => {
@@ -68,6 +72,57 @@ module.exports = { main, getParameterDefinitions }
   return filePath
 }
 
+const createImportJscad = (id, extension) => {
+  const jscadScript = `// test script ${id} -- import
+
+const main = () => {
+  return require('./test${id}.${extension}')
+}
+
+module.exports = { main }
+`
+
+  const fileName = `./test${id}-import.jscad`;
+  const filePath = path.resolve(__dirname, fileName);
+  fs.writeFileSync(filePath, jscadScript);
+  return filePath;
+}
+
+const testBackImport = (t, testID, extension) => {
+  const cliPath = t.context.cliPath;
+
+  const file4Path = createImportJscad(testID, extension);
+  t.context.file4Path = file4Path;
+  t.true(fs.existsSync(file4Path));
+
+  const file5Name = `./test${testID}-import.stl`;
+  const file5Path = path.resolve(__dirname, file5Name);
+  t.context.file5Path = file5Path;
+  t.false(fs.existsSync(file5Path));
+
+  cmd = `node ${cliPath} ${file4Path}`
+  execSync(cmd, { stdio: [0, 1, 2] })
+  t.true(fs.existsSync(file5Path));
+}
+
+const runOnFixture = (t, fixtureName) => {
+  const inputFile = path.resolve(
+    __dirname,
+    path.join('test_fixtures', fixtureName, 'index.js'));
+
+  const outputFile = inputFile.replace('.js', '.stl');
+  t.context.file1Path = outputFile;
+
+  t.false(fs.existsSync(outputFile));
+
+  const cmd = `node ${t.context.cliPath} ${inputFile}`
+  execSync(cmd, { stdio: [0, 1, 2] });
+  t.true(fs.existsSync(outputFile))
+
+  return outputFile;
+}
+
+
 test('cli (conversions STL)', (t) => {
   const testID = 11
 
@@ -87,18 +142,20 @@ test('cli (conversions STL)', (t) => {
 
   let cmd = `node ${cliPath} ${file1Path}`
   execSync(cmd, { stdio: [0, 1, 2] })
-  t.true(fs.existsSync(file2Path))
+  t.true(fs.existsSync(file2Path));
 
   // convert from STL to JSCAD script
   const file3Name = `./test${testID}.js`
   const file3Path = path.resolve(__dirname, file3Name)
-  t.false(fs.existsSync(file3Path))
+  t.false(fs.existsSync(file3Path));
 
   t.context.file3Path = file3Path
 
   cmd = `node ${cliPath} ${file2Path} -o ${file3Path} -v -add-metadata false`
   execSync(cmd, { stdio: [0, 1, 2] })
-  t.true(fs.existsSync(file3Path))
+  t.true(fs.existsSync(file3Path));
+
+  testBackImport(t, testID, 'stl');
 })
 
 test('cli (conversions DXF)', (t) => {
@@ -132,6 +189,8 @@ test('cli (conversions DXF)', (t) => {
   cmd = `node ${cliPath} ${file2Path} -of js`
   execSync(cmd, { stdio: [0, 1, 2] })
   t.true(fs.existsSync(file3Path))
+
+  testBackImport(t, testID, 'dxf');
 })
 
 test('cli (conversions AMF)', (t) => {
@@ -165,6 +224,8 @@ test('cli (conversions AMF)', (t) => {
   cmd = `node ${cliPath} ${file2Path} -of js`
   execSync(cmd, { stdio: [0, 1, 2] })
   t.true(fs.existsSync(file3Path))
+
+  testBackImport(t, testID, 'amf');
 })
 
 test('cli (conversions JSON)', (t) => {
@@ -198,6 +259,8 @@ test('cli (conversions JSON)', (t) => {
   cmd = `node ${cliPath} ${file2Path} -of js`
   execSync(cmd, { stdio: [0, 1, 2] })
   t.true(fs.existsSync(file3Path))
+
+  testBackImport(t, testID, 'json');
 })
 
 test('cli (conversions SVG)', (t) => {
@@ -264,4 +327,12 @@ test('cli (conversions X3D)', (t) => {
   cmd = `node ${cliPath} ${file2Path} -of js`
   execSync(cmd, { stdio: [0, 1, 2] })
   t.true(fs.existsSync(file3Path))
+
+  testBackImport(t, testID, 'x3d');
+})
+
+test('cli (import STL)', (t) => {
+  const testID = 17
+
+  runOnFixture(t, 'stl_import')
 })
diff --git a/packages/cli/test_fixtures/stl_import/binary_stl.stl b/packages/cli/test_fixtures/stl_import/binary_stl.stl
new file mode 100644
index 000000000..62cb2f2a3
Binary files /dev/null and b/packages/cli/test_fixtures/stl_import/binary_stl.stl differ
diff --git a/packages/cli/test_fixtures/stl_import/index.js b/packages/cli/test_fixtures/stl_import/index.js
new file mode 100644
index 000000000..457a15ddc
--- /dev/null
+++ b/packages/cli/test_fixtures/stl_import/index.js
@@ -0,0 +1,6 @@
+
+function main() {
+  return require('./binary_stl.stl');
+}
+
+module.exports = { main }
\ No newline at end of file
diff --git a/packages/core/src/io/registerExtensions.js b/packages/core/src/io/registerExtensions.js
index f6993ccad..301fa3c8e 100644
--- a/packages/core/src/io/registerExtensions.js
+++ b/packages/core/src/io/registerExtensions.js
@@ -16,8 +16,17 @@ const registerDeserializer = (extension, fs, _require) => {
   const deserializer = deserializers[extension]
   const fileExtension = '.' + extension
   _require.extensions[fileExtension] = (module, filename) => {
-    const content = fs.readFileSync(filename, 'utf8')
-    const parsed = deserializer({ filename, output: 'geometry' }, content)
+    const fileReadResult = fs.readFileSync(filename);
+
+    // https://nodejs.org/api/buffer.html#bufbuffer: Buffer.buffer is not 
+    // guaranteed to correspond exactly to the original Buffer.     
+    const fileContent = fileReadResult.buffer
+      ? fileReadResult.buffer.slice(
+        fileReadResult.byteOffset,
+        fileReadResult.byteOffset + fileReadResult.length)
+      : fileReadResult;
+
+    const parsed = deserializer({ filename, output: 'geometry' }, fileContent)
     module.exports = parsed
   }
 }
diff --git a/packages/io/amf-deserializer/package.json b/packages/io/amf-deserializer/package.json
index 98630c3dd..fe75c41b5 100644
--- a/packages/io/amf-deserializer/package.json
+++ b/packages/io/amf-deserializer/package.json
@@ -32,6 +32,7 @@
   "license": "MIT",
   "dependencies": {
     "@jscad/modeling": "2.12.3",
+    "@jscad/io-utils": "2.0.28",
     "saxes": "5.0.1"
   },
   "devDependencies": {
diff --git a/packages/io/amf-deserializer/src/index.js b/packages/io/amf-deserializer/src/index.js
index 351be483a..3db063927 100644
--- a/packages/io/amf-deserializer/src/index.js
+++ b/packages/io/amf-deserializer/src/index.js
@@ -22,6 +22,8 @@ All code released under MIT license
  * const { deserializer, extension } = require('@jscad/amf-serializer')
  */
 
+const { ensureString } = require('@jscad/io-utils')
+
 const version = require('../package.json').version
 const translate = require('./translate')
 const instantiate = require('./deserialize')
@@ -48,6 +50,7 @@ const deserialize = (options, input) => {
   }
   options = Object.assign({}, defaults, options)
 
+  input = ensureString(input);
   return options.output === 'script' ? translate(options, input) : instantiate(options, input)
 }
 
diff --git a/packages/io/dxf-deserializer/index.js b/packages/io/dxf-deserializer/index.js
index 31d98e040..28be06f5d 100644
--- a/packages/io/dxf-deserializer/index.js
+++ b/packages/io/dxf-deserializer/index.js
@@ -7,7 +7,10 @@ All code released under MIT license
 
 */
 
+const { ensureString } = require('@jscad/io-utils')
+
 const version = require('./package.json').version
+
 const { BYLAYER, getTLA } = require('./autocad')
 const colorIndex = require('./colorindex2017')
 const dxf = require('./DxfReader')
@@ -275,7 +278,7 @@ const handleXcoord = (reader, group, value) => {
   const obj = reader.objstack.pop()
   if ('type' in obj) {
     if (obj.type === 'lwpolyline') {
-    // special handling to build a list of vertices
+      // special handling to build a list of vertices
       if (obj.pptxs === undefined) {
         obj.pptxs = []
         obj.bulgs = []
@@ -284,7 +287,7 @@ const handleXcoord = (reader, group, value) => {
       obj.bulgs.push(0)
     } else {
       if (obj.type === 'mesh') {
-      // special handling to build a list of vertices
+        // special handling to build a list of vertices
         if (obj.pptxs === undefined) {
           obj.pptxs = []
         }
@@ -307,7 +310,7 @@ const handleYcoord = (reader, group, value) => {
   const obj = reader.objstack.pop()
   if ('type' in obj) {
     if (obj.type === 'lwpolyline' || obj.type === 'mesh') {
-    // special handling to build a list of vertices
+      // special handling to build a list of vertices
       if (obj.pptys === undefined) {
         obj.pptys = []
       }
@@ -329,7 +332,7 @@ const handleZcoord = (reader, group, value) => {
   const obj = reader.objstack.pop()
   if ('type' in obj) {
     if (obj.type === 'mesh') {
-    // special handling to build a list of vertices
+      // special handling to build a list of vertices
       if (obj.pptzs === undefined) {
         obj.pptzs = []
       }
@@ -351,7 +354,7 @@ const handleBulge = (reader, group, value) => {
   const obj = reader.objstack.pop()
   if ('type' in obj) {
     if (obj.type === 'lwpolyline') {
-    // special handling to build a list of vertices
+      // special handling to build a list of vertices
       const bulgs = obj.bulgs
       if (bulgs !== undefined) {
         const pptxs = obj.pptxs
@@ -376,7 +379,7 @@ const handleLen = (reader, group, value) => {
   const obj = reader.objstack.pop()
   if ('type' in obj) {
     if (obj.type === 'mesh') {
-    // mesh has an order of lengths
+      // mesh has an order of lengths
       const state = obj.state
       // console.log('mesh len: '+group+','+value+','+state)
       switch (group) {
@@ -600,6 +603,8 @@ const deserialize = (options, src) => {
     }
   }
   options = Object.assign({}, defaults, options)
+
+  src = ensureString(src);
   return options.output === 'script' ? translate(src, options) : instantiate(src, options)
 }
 
diff --git a/packages/io/dxf-deserializer/package.json b/packages/io/dxf-deserializer/package.json
index 48c490489..4f1e516bb 100644
--- a/packages/io/dxf-deserializer/package.json
+++ b/packages/io/dxf-deserializer/package.json
@@ -28,7 +28,8 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "@jscad/modeling": "2.12.3"
+    "@jscad/modeling": "2.12.3",
+    "@jscad/io-utils": "2.0.28"
   },
   "devDependencies": {
     "ava": "3.15.0",
diff --git a/packages/io/io-utils/ensureString.js b/packages/io/io-utils/ensureString.js
new file mode 100644
index 000000000..f15eae94e
--- /dev/null
+++ b/packages/io/io-utils/ensureString.js
@@ -0,0 +1,9 @@
+const ensureString = (stringOrArrayBuffer, defaultBinaryEncoding = 'utf-8') => {
+  if (typeof (stringOrArrayBuffer) === 'string') {
+    return stringOrArrayBuffer;
+  }
+
+  return new TextDecoder(defaultBinaryEncoding).decode(new Uint8Array(stringOrArrayBuffer));
+}
+
+module.exports = ensureString;
\ No newline at end of file
diff --git a/packages/io/io-utils/index.js b/packages/io/io-utils/index.js
index 13dee02d0..d307c5762 100644
--- a/packages/io/io-utils/index.js
+++ b/packages/io/io-utils/index.js
@@ -8,5 +8,6 @@ module.exports = {
   convertToBlob: require('./convertToBlob'),
   makeBlob: require('./makeBlob'),
   BinaryReader: require('./BinaryReader'),
-  Blob: require('./Blob')
+  Blob: require('./Blob'),
+  ensureString: require('./ensureString')
 }
diff --git a/packages/io/json-deserializer/index.js b/packages/io/json-deserializer/index.js
index 7ac3676b6..dd6f20ff8 100644
--- a/packages/io/json-deserializer/index.js
+++ b/packages/io/json-deserializer/index.js
@@ -21,6 +21,7 @@ All code released under MIT license
  */
 
 const { flatten, toArray } = require('@jscad/array-utils')
+const { ensureString } = require('@jscad/io-utils')
 
 const version = require('./package.json').version
 
@@ -45,6 +46,7 @@ const deserialize = (options, input) => {
   options = Object.assign({}, defaults, options)
 
   // convert the JSON notation into anonymous object(s)
+  input = ensureString(input);
   let objects = JSON.parse(input)
 
   // cleanup the objects
@@ -69,7 +71,7 @@ const translate = (options, objects) => {
     : ''
 
   script +=
-`
+    `
 const { geometries } = require('@jscad/modeling')
 
 const main = () => {
diff --git a/packages/io/json-deserializer/package.json b/packages/io/json-deserializer/package.json
index 7a8cd0c54..4c1048a5f 100644
--- a/packages/io/json-deserializer/package.json
+++ b/packages/io/json-deserializer/package.json
@@ -28,7 +28,8 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "@jscad/array-utils": "2.1.4"
+    "@jscad/array-utils": "2.1.4",
+    "@jscad/io-utils": "2.0.28"
   },
   "devDependencies": {
     "@jscad/modeling": "2.12.3",
diff --git a/packages/io/obj-deserializer/index.js b/packages/io/obj-deserializer/index.js
index a0e455b75..11ab47cee 100644
--- a/packages/io/obj-deserializer/index.js
+++ b/packages/io/obj-deserializer/index.js
@@ -1,4 +1,5 @@
 const { colors, primitives } = require('@jscad/modeling')
+const { ensureString } = require('@jscad/io-utils')
 
 const version = require('./package.json').version
 
@@ -32,6 +33,8 @@ const deserialize = (options, input) => {
   options = Object.assign({}, defaults, options)
   const { output } = options
 
+  input = ensureString(input);
+
   options && options.statusCallback && options.statusCallback({ progress: 0 })
 
   const { positions, groups } = getGroups(input, options)
diff --git a/packages/io/obj-deserializer/package.json b/packages/io/obj-deserializer/package.json
index 92d3cb18b..957875fda 100644
--- a/packages/io/obj-deserializer/package.json
+++ b/packages/io/obj-deserializer/package.json
@@ -32,7 +32,8 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "@jscad/modeling": "2.12.3"
+    "@jscad/modeling": "2.12.3",
+    "@jscad/io-utils": "2.0.28"
   },
   "devDependencies": {
     "ava": "3.15.0",
diff --git a/packages/io/svg-deserializer/package.json b/packages/io/svg-deserializer/package.json
index f8da9af66..c0a0eec85 100644
--- a/packages/io/svg-deserializer/package.json
+++ b/packages/io/svg-deserializer/package.json
@@ -34,6 +34,7 @@
   "dependencies": {
     "@jscad/array-utils": "2.1.4",
     "@jscad/modeling": "2.12.3",
+    "@jscad/io-utils": "2.0.28",
     "saxes": "5.0.1"
   },
   "devDependencies": {
diff --git a/packages/io/svg-deserializer/src/index.js b/packages/io/svg-deserializer/src/index.js
index 2161044e5..879d6f6f8 100644
--- a/packages/io/svg-deserializer/src/index.js
+++ b/packages/io/svg-deserializer/src/index.js
@@ -14,6 +14,7 @@ const saxes = require('saxes')
 
 const { colors, transforms } = require('@jscad/modeling')
 const { toArray } = require('@jscad/array-utils')
+const { ensureString } = require('@jscad/io-utils')
 
 const version = require('../package.json').version
 
@@ -22,6 +23,7 @@ const { svgSvg, svgRect, svgCircle, svgGroup, svgLine, svgPath, svgEllipse, svgP
 const shapesMapGeometry = require('./shapesMapGeometry')
 const shapesMapJscad = require('./shapesMapJscad')
 
+
 /**
  * Deserializer of SVG source data to JSCAD geometries.
  * @see {@link https://github.com/jscad/OpenJSCAD.org/blob/master/packages/io/svg-deserializer/README.md|README} for supported conversion of SVG elements.
@@ -58,6 +60,7 @@ const deserialize = (options, input) => {
     version
   }
   options = Object.assign({}, defaults, options)
+  input = ensureString(input);
   return options.output === 'script' ? translate(input, options) : instantiate(input, options)
 }
 
@@ -395,7 +398,7 @@ const createSvgParser = (src, pxPmm) => {
           if (svgGroups.length > 0) {
             const group = svgGroups.pop()
             if ('objects' in group) {
-            // TBD apply presentation attributes from the group
+              // TBD apply presentation attributes from the group
               group.objects.push(obj)
             }
             svgGroups.push(group)
@@ -422,7 +425,7 @@ const createSvgParser = (src, pxPmm) => {
       DEFS: () => { svgInDefs = false },
       USE: popGroup,
       G: popGroup,
-      undefined: () => {}
+      undefined: () => { }
     }
     const elementName = node.name.toUpperCase()
     const obj = objMap[elementName] ? objMap[elementName]() : undefined
diff --git a/packages/io/x3d-deserializer/package.json b/packages/io/x3d-deserializer/package.json
index 09188d5cd..1f5afe9ea 100644
--- a/packages/io/x3d-deserializer/package.json
+++ b/packages/io/x3d-deserializer/package.json
@@ -28,6 +28,7 @@
   "dependencies": {
     "@jscad/array-utils": "2.1.4",
     "@jscad/modeling": "2.12.3",
+    "@jscad/io-utils": "2.0.28",
     "saxes": "5.0.1"
   },
   "devDependencies": {
diff --git a/packages/io/x3d-deserializer/src/index.js b/packages/io/x3d-deserializer/src/index.js
index 622c7d195..4413cf749 100644
--- a/packages/io/x3d-deserializer/src/index.js
+++ b/packages/io/x3d-deserializer/src/index.js
@@ -20,12 +20,14 @@ All code released under MIT license
  * @example
  * const { deserializer, extension } = require('@jscad/x3d-deserializer')
  */
+const { ensureString } = require('@jscad/io-utils')
 
 const version = require('../package.json').version
 
 const translate = require('./translate')
 const instantiate = require('./instantiate')
 
+
 /**
  * Deserialize the given X3D source (XML Encoding) into either a script or an array of geometry
  * @see {@link https://www.web3d.org/documents/specifications/19776-1/V3.3/index.html|X3D File Format}
@@ -48,7 +50,7 @@ const deserialize = (options, input) => {
     addMetaData: true
   }
   options = Object.assign({}, defaults, options)
-
+  input = ensureString(input);
   return options.output === 'script' ? translate(options, input) : instantiate(options, input)
 }