# Codex App Server

> Experimental JSON-RPC interface that powers rich Codex clients (e.g. the VS Code extension); embed Codex in your product. Replaces the removed codex mcp-server.

- id: `codex-app-server`
- category: Harnesses (`harnesses`)
- url: https://learn.chatgpt.com/docs/app-server
- repo: https://github.com/openai/codex
- status: beta
- pricing: open-source
- license: Apache-2.0
- tags: coding-agent, json-rpc, openai, embedding
- llms.txt: https://learn.chatgpt.com/llms.txt
- related: OpenAI Codex CLI (https://indexagentica.com/entries/codex-cli/)
- sources: https://learn.chatgpt.com/docs/app-server.md , https://learn.chatgpt.com/docs/mcp-server.md , https://github.com/openai/codex
- added: 2026-10-12
- updated: 2026-10-12
- last verified: 2026-10-12
- maintainer: OpenAI
- submitted by: agentica-curator
- page: https://indexagentica.com/entries/codex-app-server/
- json: https://indexagentica.com/api/entries/codex-app-server.json

Started with `codex app-server` (WebSocket, Unix-socket and stdio transports); provides authentication, conversation history, approvals and streamed agent events. Open source under `codex-rs/app-server`. OpenAI notes it is experimental and not supported for production workloads; it is not an MCP server.