---
title: "Create an OpenAI-compatible response"
method: POST
path: "/ai/openai/responses"
tags: ["OpenAI Chat"]
---

# Create an OpenAI-compatible response

`POST /ai/openai/responses`

Create a response using Telnyx's OpenAI-compatible Responses API. This endpoint is compatible with the [OpenAI Responses API](https://developers.openai.com/api/reference/responses/overview) and may be used with the OpenAI JS or Python SDK by setting the base URL to `https://api.telnyx.com/v2/ai/openai`.

The `conversation` parameter refers to a Telnyx Conversation rather than an OpenAI-hosted conversation object. To persist a thread across turns, first [create a conversation](https://developers.telnyx.com/api-reference/conversations/create-a-conversation) with `POST /ai/conversations`, then pass that conversation's `id` in the Responses request as `conversation`. The endpoint appends the new input, assistant output, reasoning, and tool-call messages to that conversation. Reuse the same `conversation` id on subsequent Responses requests, including tool-result followups, so the model receives the prior context.

If `conversation` is omitted, the request is processed without persisting messages to a Telnyx conversation. Use the Conversations API to manage history: [list conversations](https://developers.telnyx.com/api-reference/conversations/list-conversations) (optionally filtered by metadata), [fetch messages](https://developers.telnyx.com/api-reference/conversations/get-conversation-messages) for a conversation, and optionally [add messages](https://developers.telnyx.com/api-reference/conversations/create-message) outside the Responses flow.

You can attach arbitrary metadata when creating a conversation (for example to tag the conversation's source, channel, or user) and later filter by it when listing conversations.

## Request body

- object
  - `model` string — Model identifier to use for the response, for example `zai-org/GLM-5.1-FP8` or another model available from the Telnyx OpenAI-compatible models endpoint.
  - `service_tier` string — The service tier to use for this request. Supported values vary by model; use `GET /v2/ai/openai/models` and inspect the model's `service_tiers` field. If omitted, Telnyx-hosted models use `default`.
  - `region` 'USA' | 'EU' | 'AUS' | 'UAE' — Optional data-residency region the request should be served from, using the same vocabulary as your account's Data Locality setting. Behavior depends on `mode`. Supported for Telnyx-hosted models only: a request routed to an external provider never passes through Telnyx model routing, so a region cannot be enforced for it. Omit for today's latency-based routing.
  - `mode` 'preferred' | 'strict' — How strictly `region` is applied. `preferred` (the default when `region` is set) tries that region first and falls back to another when the model cannot be served there, so a request that would have succeeded still succeeds. `strict` pins the request: it is served from that region or it fails with a 422, never redirected to another region. Requires `region`.
  - `input` unknown
  - `conversation` string, uuid — Optional Telnyx Conversation ID from `POST /ai/conversations`. When provided, Telnyx stores this turn on that conversation and uses the conversation's prior messages as context. Reuse the same ID for subsequent turns and tool-result followups. Omit it for a non-persisted, stateless response.
  - `instructions` string — Optional system/developer instructions for the model. When used with a persisted `conversation`, send these on the first request that creates the thread; subsequent turns can rely on the stored history.
  - `stream` boolean — Set to `true` to stream Server-Sent Events, matching OpenAI's Responses streaming format.
  - `reasoning` object
    - `effort` 'none' | 'minimal' | 'low' | 'medium' | 'high' | 'xhigh' | 'max' — Controls the reasoning effort for models that support it. Same values and semantics as reasoning_effort on Chat Completions.

## Response `200`

Successful Response

- object

## Other responses

- `422` — Validation Error

## Changes

> 93 revisions in range; 1 not diffed.

- **2026-09-16** `a6a61a29ecdd` — 3 info
  - added the new optional request property `mode`
  - added the new optional request property `reasoning`
  - added the new optional request property `region`
- **2026-07-29** `f8c0ade27450` — 1 info
  - added the new optional request property `service_tier`

[Change history](https://skmtc.dev/team-telnyx/apis/telnyx-api-2/changes/ai/openai/responses/post.md)

---

[API](https://skmtc.dev/team-telnyx/apis/telnyx-api-2.md) · [All operations](https://skmtc.dev/team-telnyx/apis/telnyx-api-2/llms.txt) · [OpenAPI document](https://skmtc.dev/team-telnyx/apis/telnyx-api-2/revisions/88481995b4ca?raw)