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The SLNG Unified API is a normalization layer across every speech model provider.

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The problem it solves

Every speech provider has its own way of doing things: own request format, own error handling, own parameters. When you want to move an integration from model A to model B, you usually have to build and maintain a second integration. That means one SDK per provider, different request formats, provider-specific error handling, and weeks spent evaluating each new model.

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How it works

You call a model available on the SLNG gateway, and the Unified API translates the request into whatever each provider expects, then translates the answer back.
  • Authentication, request format, and responses stay the same across every model.
  • To switch providers, you only change which model you point to.
  • It covers both speech to text (STT) and text to speech (TTS).
  • SLNG-hosted models and third-party models sit behind the same unification.
When you need a model’s provider-native parameters, call its direct endpoint instead. The Unified API guide compares the two and lists the fields each transport accepts.

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Powers our third-party integrations

The Unified API also powers our integrations with the major voice agent frameworks. In LiveKit and Pipecat, developers name the model they want, and the SLNG plugins connect through the Unified API automatically. Switching providers is a change to the model name, with no other code changes. To make your first request, follow the Unified API guide.