Convert, trim, transcribe, and synthesize audio — all in your browser. No uploads, no accounts, 100% open source.
Use the tools online, or download and run them locally. Contribute, fork, build upon — it's MIT licensed.
AudioTools is a collection of free, open-source audio tools that run entirely in your browser. No files are uploaded to any server — all processing happens locally using modern Web APIs (Web Audio API, Web Speech API, MediaRecorder API). Every tool is free, with no limits, no ads, and no account required.
Convert between WAV, MP3, FLAC, OGG, AAC, M4A, and WebM formats. The audio converter decodes your audio file using the Web Audio API, then re-encodes it in the target format. WAV encoding is native, MP3 uses the LAME encoder compiled to WebAssembly, and FLAC uses a custom WASM encoder. File sizes up to several hundred MB are supported depending on your device's memory.
Real-time speech transcription using the Web Speech Recognition API. The voice-to-text tool supports 60+ languages including English, Spanish, French, German, Japanese, Chinese, Korean, Russian, Arabic, Hindi, and many more. Punctuation and formatting are automatic. Great for transcribing meetings, lectures, interviews, and voice notes.
Convert written text to natural-sounding speech using the Web Speech Synthesis API. The text-to-speech tool offers 50+ voices across dozens of languages. Adjust speed (0.25x to 3x), pitch, and volume. Useful for proofreading, language learning, accessibility, and content creation.
Cut and trim audio files with a visual waveform editor. The audio trimmer shows your file as a waveform — drag the start and end handles to select the portion you want, preview the selection, and download the result as WAV. Uses OfflineAudioContext for precise sample-accurate trimming.
Modern browsers include powerful audio processing capabilities through the Web Audio API. When you load a file, the browser decodes it into raw PCM audio data (an AudioBuffer). This data can then be processed — trimmed, converted, analyzed, or played back — entirely in JavaScript. The result is encoded back into a file format and downloaded. No network requests are made during processing.
AudioTools takes a zero-knowledge approach: your audio files and voice data never leave your device. There are no analytics trackers, no cookies, and no server-side processing. The entire source code is available on GitHub under the MIT license for full transparency.
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