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

The problem it solves

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

How it works

You call a model available in SLNG gateway, and the Unified API translates it 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 they point to.
  • It covers both STT (speech-to-text) and TTS (text-to-speech).
  • SLNG-hosted models and third-party models sit behind the same unification.

What it unlocks

  • Freedom to switch. New and better models become available as soon as SLNG adds them, with no upgrade work on the customer’s side.
  • Easy testing. Teams can send a share of their traffic to a different model to compare results, try new models in minutes, and fall back to another provider without changing how they handle errors.
  • No loss of control. The Unified API lets you do anything. Settings like voice, language, audio format, and speed can still be passed through.

Powers our 3rd 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. Get started quick with this guide.