sherpa-onnx public API documentation

This documentation covers the public native APIs shipped in:

• c-api.h — the C API
• cxx-api.h — the C++ wrapper built on top of the C API

These headers expose the main sherpa-onnx inference features for native applications and for language bindings that need a stable ABI.

What is documented here

The generated docs include the public APIs for:

• streaming ASR
• non-streaming ASR
• keyword spotting
• voice activity detection
• offline text-to-speech
• spoken language identification
• speaker embedding extraction and speaker management
• audio tagging
• offline and online punctuation
• linear resampling
• offline speaker diarization
• offline and online speech enhancement

The C API also includes HarmonyOS-specific constructor variants where applicable.

Which header should I use?

Use c-api.h if you are:

• writing C code
• building FFI bindings for other languages
• integrating through a plain C ABI

Use cxx-api.h if you are:

• writing C++ code directly
• preferring RAII wrappers over manual destroy/free calls
• preferring std::string, std::vector, and move-only wrapper classes

Common ownership rules

For the C API:

• objects created by SherpaOnnxCreate*() are usually destroyed with a matching SherpaOnnxDestroy*()
• result snapshots, returned strings, and returned arrays must be released with the specific matching free/destroy function documented on each API
• some helpers return pointers to statically owned strings; those must not be freed

For the C++ API:

• wrapper classes are move-only and use RAII
• copied result objects are returned as standard C++ value types
• callers normally do not need to manage the underlying C pointers directly

Typical workflow

For both APIs, the usual flow is:

1. create and fill a config object
2. create the engine or recognizer
3. create a stream if the feature is stream-based
4. feed audio or text
5. run decode/compute/generate
6. read back results
7. destroy resources, or let the C++ wrappers clean them up automatically

Recommended entry points

Start with:

• c-api.h for the plain C API
• cxx-api.h for the C++ wrapper

Representative example programs live in:

• c-api-examples/
• cxx-api-examples/

Useful examples include:

• decode-file-c-api.c
• whisper-c-api.c
• cohere-transcribe-c-api.c
• sense-voice-c-api.c
• nemo-parakeet-c-api.c
• streaming-zipformer-with-hr-cxx-api.cc
• sense-voice-cxx-api.cc
• pocket-tts-en-cxx-api.cc
• vad-cxx-api.cc

Generating the documentation

From sherpa-onnx/c-api/, run:

doxygen Doxyfile

HTML output is written to:

doxygen-docs/html/