Codex is OpenAI's open-source coding agent for the terminal. It works from natural-language instructions to edit code across your project, run commands, and complete tasks end to end, with its source available on GitHub under Apache-2.0. On Opper, launch it on GPT, Claude, Gemini, DeepSeek and 700+ more — one key, automatic fallbacks, and a choice of region.
CodexoninPaste this into your coding agent (Claude Code, Cursor, Codex, and more) and it will set up and build with Opper for you.
Run Codex on GLM-5.3 hosted in the EU on the routes below.
GLM-5.3 by Z.ai is a 744B open-weight coding and agentic model, post-trained on the GLM-5.2 base with a 1M-token context and low, high, and max reasoning effort levels.
Step-by-step setup for running Codex on each of these models through Opper.
Anthropic's terminal coding agent. Run it on any model on Opper, not just Claude.
opper launch claude
DeepSeek's open-source coding agent. Add Opper as a custom provider to run it on any model, not just DeepSeek's.
OpenAI-compatible
GitHub's terminal coding agent. Point its provider variables at Opper to run it on any model, no Copilot plan required.
OpenAI-compatible