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.
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