Speechify-Version gives API clients a stable date pin

1 min read

Speechify APIs now support the Speechify-Version header, so HTTP clients can pin a dated contract while SDKs send their build-date version automatically.

Developer Relations · SpeechifyAI Labs

Speechify APIs now accept a dated Speechify-Version request header. Send a date like 2026-06-25 and the API resolves your request against that contract instead of silently moving you onto a newer wire shape.

This is the same idea developers already expect from Stripe-style API versioning. Raw HTTP callers can set the header themselves, and official SDKs send their build-date version automatically.

What changed?

The version resolution order is now:

  1. request header
  2. workspace default
  3. oldest supported version

That means an integration can pin its behavior before a response field changes, then move forward on purpose after it has tested the newer shape.

The first versioned change is already live in Agents. GET /v1/agents/llm-models moved from flat platform_default_provider and platform_default_model fields to a nested platform_default object. Pin 2026-06-24 or earlier to keep the old shape, or read platform_default.provider and platform_default.model on 2026-06-25 and later.

Where should I read more?

The docs changelog entries have the short migration notes:

This post is intentionally brief. The docs entries are the source of truth for the release shape.