May 27, 2026 | OpenRouter

Series B announcement — Published the $113M Series B announcement.
API tab redesign on model pages — Each model’s API tab now shows the /responses and /messages endpoint references alongside /chat/completions, making it easier to discover alternative request formats. Docs
Presets: Anthropic Messages API support — Created presets from inference now support POST /api/v1/presets/:slug/messages, the Anthropic Messages counterpart to the existing chat/completions preset route. Docs
Stream inactivity timeout — Streaming requests that produce no chunks for 30 seconds are now aborted immediately instead of waiting up to 5 minutes, catching dead connections and empty streams faster.
Guardrails API documentation — Added a guide for updating your workspace default guardrail programmatically via the API. Docs
Fixed: EU routing for non-Google models on Vertex — Non-Google models (Claude, Llama, DeepSeek, etc.) routed through eu.openrouter.ai now use the correct endpoint path, fixing 400 errors caused by a hostname/path mismatch.

Series B announcement — Published the $113M Series B announcement.
API tab redesign on model pages — Each model’s API tab now shows the /responses and /messages endpoint references alongside /chat/completions, making it easier to discover alternative request formats. Docs
Presets: Anthropic Messages API support — Created presets from inference now support POST /api/v1/presets/:slug/messages, the Anthropic Messages counterpart to the existing chat/completions preset route. Docs
Stream inactivity timeout — Streaming requests that produce no chunks for 30 seconds are now aborted immediately instead of waiting up to 5 minutes, catching dead connections and empty streams faster.
Guardrails API documentation — Added a guide for updating your workspace default guardrail programmatically via the API. Docs
Fixed: EU routing for non-Google models on Vertex — Non-Google models (Claude, Llama, DeepSeek, etc.) routed through eu.openrouter.ai now use the correct endpoint path, fixing 400 errors caused by a hostname/path mismatch.

Changelog