diff --git a/build/transpile.js b/build/transpile.js
index 1b16b420dec8..bc727cfd7bfb 100644
--- a/build/transpile.js
+++ b/build/transpile.js
@@ -5,6 +5,7 @@
 "use strict";
 
 const fs = require ('fs')
+    , { promisify } = require("util")
     , log = require ('ololog').unlimited
     , _ = require ('ansicolor').nice
     , errors = require ('../js/base/errors.js')
@@ -26,8 +27,8 @@ const fs = require ('fs')
     , Exchange = require ('.' + baseExchangeJsFile)
     , tsFilename = './ccxt.d.ts'
     , pythonCodingUtf8 = '# -*- coding: utf-8 -*-'
-const {ids: exchanges} = require("../exchanges.json");
 
+const exchangeIds = require("../exchanges.json").ids;
 class Transpiler {
 
     getCommonRegexes () {
@@ -1446,6 +1447,20 @@ class Transpiler {
 
     // ========================================================================
 
+    async getTSClassDeclarationsAllFiles (ids, folder, extension = '.js')  {
+        const files = fs.readdirSync (folder).filter (file => ids.includes (basename (file, extension)))
+        const promiseReadFile = promisify (fs.readFile);
+        const fileArray = await Promise.all (files.map (file => promiseReadFile (folder + file, 'utf8')));
+        const classComponents = await Promise.all (fileArray.map (file => this.getClassDeclarationMatches (file)));
+
+        const classes = {}
+        classComponents.forEach ( elem => classes[elem[1]] = elem[2] );
+
+        return classes
+    }
+
+    // ========================================================================
+
     exportTypeScriptClassNames (file, classes) {
 
         log.bright.cyan ('Exporting TypeScript class names →', file.yellow)
@@ -1471,7 +1486,9 @@ class Transpiler {
         replaceInFile (file, regex, replacement)
     }
 
-    exportTypeScriptDeclarations (file, classes) {
+    async exportTypeScriptDeclarations (file, jsFolder) {
+
+        const classes = await this.getTSClassDeclarationsAllFiles (exchangeIds, jsFolder);
 
         this.exportTypeScriptClassNames (file, classes)
         this.exportTypeScriptExchangeIds (file, classes)
@@ -1912,7 +1929,7 @@ class Transpiler {
 
     // ============================================================================
 
-    transpileEverything (force = false, child = false) {
+    async transpileEverything (force = false, child = false) {
 
         // default pattern is '.js'
         const exchanges = process.argv.slice (2).filter (x => !x.startsWith ('--'))
@@ -1920,6 +1937,7 @@ class Transpiler {
             , python3Folder  = './python/ccxt/async_support/'
             , phpFolder      = './php/'
             , phpAsyncFolder = './php/async/'
+            , jsFolder = './js/'
             , options = { python2Folder, python3Folder, phpFolder, phpAsyncFolder, exchanges }
 
         if (!child) {
@@ -1931,7 +1949,7 @@ class Transpiler {
 
         //*
 
-        const classes = this.transpileDerivedExchangeFiles ('./js/', options, '.js', force, child || exchanges.length)
+        const classes = this.transpileDerivedExchangeFiles (jsFolder, options, '.js', force, child || exchanges.length)
 
         if (classes === null) {
             log.bright.yellow ('0 files transpiled.')
@@ -1944,7 +1962,7 @@ class Transpiler {
         this.transpileBaseMethods ()
         // HINT: if we're going to support specific class definitions
         // this process won't work anymore as it will override the definitions
-        this.exportTypeScriptDeclarations (tsFilename, classes)
+        await this.exportTypeScriptDeclarations (tsFilename, jsFolder)
 
         //*/
 
@@ -1994,10 +2012,11 @@ if (require.main === module) { // called directly like `node module`
     } else if (errors) {
         transpiler.transpileErrorHierarchy ({ tsFilename })
     } else if (multiprocess) {
-        const exchanges = require ('../exchanges.json').ids
-        parallelizeTranspiling (exchanges)
+        parallelizeTranspiling (exchangeIds)
     } else {
-        transpiler.transpileEverything (force, child)
+        (async () => {
+            await transpiler.transpileEverything (force, child)
+        })()
     }
 
 } else { // if required as a module
diff --git a/build/transpileWS.js b/build/transpileWS.js
index f0e776310d82..d10c048684c4 100644
--- a/build/transpileWS.js
+++ b/build/transpileWS.js
@@ -18,6 +18,8 @@ const fs = require ('fs')
     , Exchange = require ('../js/pro/base/Exchange.js')
     , tsFilename = './ccxt.d.ts'
 
+    const wsExchangeIds = require ('../exchanges.json').ws
+
 // ============================================================================
 
 class CCXTProTranspiler extends Transpiler {
@@ -242,14 +244,15 @@ class CCXTProTranspiler extends Transpiler {
     
     // -----------------------------------------------------------------------
     
-    exportTypeScriptDeclarations (file, classes) {
+    async exportTypeScriptDeclarations (file, jsFolder) {
 
+        const classes = await this.getTSClassDeclarationsAllFiles (wsExchangeIds, jsFolder);
         this.exportTypeScriptClassNames (file, classes)
     }
 
     // -----------------------------------------------------------------------
     
-    transpileEverything (force = false, child = false) {
+    async transpileEverything (force = false, child = false) {
 
         // default pattern is '.js'
         // const [ /* node */, /* script */, pattern ] = process.argv.filter (x => !x.startsWith ('--'))
@@ -257,13 +260,14 @@ class CCXTProTranspiler extends Transpiler {
             // , python2Folder = './python/ccxtpro/', // CCXT Pro does not support Python 2
             , python3Folder = './python/ccxt/pro/'
             , phpAsyncFolder     = './php/pro/'
+            , jsFolder = './js/pro/'
             , options = { /* python2Folder, */ python3Folder, phpAsyncFolder, exchanges }
 
         // createFolderRecursively (python2Folder)
         createFolderRecursively (python3Folder)
         createFolderRecursively (phpAsyncFolder)
 
-        const classes = this.transpileDerivedExchangeFiles ('./js/pro/', options, '.js', force, child || exchanges.length)
+        const classes = this.transpileDerivedExchangeFiles (jsFolder, options, '.js', force, child || exchanges.length)
 
         if (child) {
             return
@@ -280,7 +284,7 @@ class CCXTProTranspiler extends Transpiler {
 
         // HINT: if we're going to support specific class definitions
         // this process won't work anymore as it will override the definitions
-        this.exportTypeScriptDeclarations (tsFilename, classes)
+        await this.exportTypeScriptDeclarations (tsFilename, jsFolder)
 
         //*/
 
@@ -309,10 +313,11 @@ if (require.main === module) {
         log.bright.green ({ force })
     }
     if (multiprocess) {
-        const exchanges = require ('../exchanges.json').ws
-        parallelizeTranspiling (exchanges)
+        parallelizeTranspiling (wsExchangeIds)
     } else {
-        transpiler.transpileEverything (force)
+        (async () => {
+            await transpiler.transpileEverything (force, child)
+        })()
     }
 
 } else {
diff --git a/package.json b/package.json
index 92f117e6fec3..63eb8b46c9c7 100644
--- a/package.json
+++ b/package.json
@@ -18,7 +18,8 @@
   "scripts": {
     "docker": "docker-compose run --rm ccxt",
     "build": "npm run pre-transpile && npm run transpile && npm run post-transpile && npm run update-badges",
-    "force-build": "npm run pre-transpile && npm run force-transpile && npm run post-transpile && npm run update-badges",
+    "force-build": "npm run pre-transpile && npm run force-transpile-fast && npm run post-transpile && npm run update-badges",
+    "force-build-slow": "npm run pre-transpile && npm run force-transpile && npm run post-transpile && npm run update-badges",
     "pre-transpile": "npm run export-exchanges && npm run vss && npm run copy-python-files && npm run check-js-syntax && npm run browserify",
     "post-transpile": "npm run check-python-syntax && npm run check-php-syntax",
     "test-ws": "npm run build && node run-tests-ws",
@@ -53,6 +54,7 @@
     "transpileRest": "node build/transpile",
     "transpileWs": "node build/transpileWS",
     "force-transpile": "npm run force-transpileRest && npm run force-transpileWs",
+    "force-transpile-fast": "npm run dev-force-transpile",
     "dev-force-transpile": "npm run fast-force-transpileRest && npm run fast-force-transpileWs",
     "force-transpileRest": "node build/transpile --force",
     "fast-force-transpileRest": "node build/transpile.js --multiprocess",
@@ -91,7 +93,8 @@
     "eslint-config-airbnb-base": "15.0.0",
     "eslint-plugin-import": "2.25.4",
     "https-proxy-agent": "^5.0.1",
-    "ololog": "1.1.155"
+    "ololog": "1.1.155",
+    "replace-in-file": "^6.3.5"
   },
   "author": {
     "name": "Igor Kroitor",
@@ -625,7 +628,6 @@
   },
   "ethereum": "0x26a3CB49578F07000575405a57888681249c35Fd",
   "dependencies": {
-    "replace-in-file": "^6.3.5",
     "ws": "^8.8.1"
   }
 }