Open Codex – OpenAI Codex CLI with open-source LLMs
Hey HN, I’ve built Open Codex, a fully local, open-source alternative to OpenAI’s Codex CLI. My initial plan was to fork their project and extend it. I even started doing that. But it turned out their code has several leaky abstractions, which made it hard to override core behavior cleanly. Shortly after, OpenAI introduced breaking changes. Maintaining my customizations on top became increasingly difficult. So I rewrote the whole thing from scratch using Python. My version is designed to support local LLMs. Right now, it only works with phi-4-mini (GGUF) via…
Open Codex – OpenAI Codex CLI with open-source LLMs launched on April 21, 2025 with 106 votes, #464 of 7,818 launches that month and more than 95% of that year's launches. The site was still online in September 2026, 1 year on.
In plain words
Open Codex is a command-line tool that runs locally on users' computers as an open-source alternative to OpenAI's Codex. Built in Python, it uses open-source language models like phi-4-mini to assist with code generation without requiring cloud connectivity or external services. The tool is designed for developers who want code assistance capabilities running entirely on their own hardware, with plans to expand model support and add interactive chat mode and function calling features.
written from the facts on this page · September 2026
From the sources
Fully open-source command-line AI assistant inspired by OpenAI Codex, supporting local language models. - codingmoh/open-codex
Open Codex is a fully open-source command-line AI assistant inspired by OpenAI Codex, supporting local language models like phi-4-mini and full integration with Ollama . 🧠 Runs 100% locally – no OpenAI API key required. Everything works offline. 🛠️ You must have Ollama installed and running locally to use this feature. brew tap codingmoh/open-codex brew install open-codex 🔹 Option 2: Install via pipx (Cross-platform) pipx install open-codex 🔹 Option 3: Clone & install locally git clone https://github.com/codingmoh/open-codex.git cd open_codex pip install . Once installed, use the open-codex CLI globally. open-codex " untar file abc.tar " ✅ Codex suggests a shell command ✅ Asks for…from github.com
In the maker’s words, at launch
Hey HN, I’ve built Open Codex, a fully local, open-source alternative to OpenAI’s Codex CLI. My initial plan was to fork their project and extend it. I even started doing that. But it turned out their code has several leaky abstractions, which made it hard to override core behavior cleanly. Shortly after, OpenAI…
Does a similar job
all alternatives →
Open-Source Alternative to OpenAI Platform, for Local Models2025 · github.com · ▲93Hi everyone, we’re a small team, supported by Mozilla, who are working on re-imagining a UI for training, tuning and testing local LLMs. Everything is open source. If you’ve been training your own LLMs or have always wanted to, we’d love for you to play with the tool and give feedback on what the future development experience for LLM engineering could look like.
Codex app for WindowsMar 2026 · learn.chatgpt.com · ▲145Codex now runs natively on Windows with secure sandbox
My LLM CLI tool can run tools now, from Python code or plugins2025 · simonwillison.net · ▲529LLM 0.26 is out with the biggest new feature since I started the project: support for tools. You can now use the LLM CLI tool—and Python library—to grant LLMs from …
OpenCode SuperappJul 2026 · opencodesuper.app · ▲128The power of Codex with local, self-hosted models and voice
I built an OSS alternative to Azure OpenAI services2023 · github.com · ▲200Hey HN, I am proud to show you guys that I have built an open source alternative to Azure OpenAI services. Azure OpenAI services was born out of companies needing enhanced security and access control for using different GPT models. I want to build an OSS version of Azure OpenAI services that people could self host in their own infrastructure. "How can I track LLM spend per API key?" "Can I create a development OpenAI API key with limited access for Bob?" "Can I see my LLM spend breakdown by models and endpoints?" "Can I create 100 OpenAI API keys that my students could use in a classroom…
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Source: Show HN post ↗ · launch text quoted in part
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