# OpenAI Reveals Technical Details Behind Codex App Server Integration

OpenAI has published new technical documentation explaining how developers can integrate the Codex AI coding agent into their applications using the Codex App Server.

The announcement, shared on OpenAI's official account, introduces what the company calls the "Codex harness" – a system that allows developers to embed Codex's capabilities directly into their own software. At its core is a bidirectional JSON-RPC API, a communication protocol that enables real-time, two-way data exchange between applications and the Codex agent.

Key features of the App Server include streaming progress updates, which let users see Codex working in real-time rather than waiting for final results. The system also supports tool use, allowing Codex to interact with external functions and services, along with approval workflows that give users control over what actions the AI can execute. Additionally, it includes diff