Codex alternatives compared: price, plans and background runs
| Tool | What it is | Pricing (official) | Subscriptions or keys it can use | Runs in background |
|---|---|---|---|---|
| Codex | OpenAI's coding agent: CLI, IDE extension, desktop and web app, Codex cloud | Limited in ChatGPT Free and Go ($8); Plus $20; Pro $100, $200 or $500 a month | ChatGPT plan sign-in, or an OpenAI API key (no cloud features) | Yes: Codex cloud, on Plus and higher plans |
| Claude Code | Anthropic's coding agent for the terminal, IDE, desktop and web | Pro $20 a month ($17 billed annually); Max $100; Ultra $200 | Claude Pro, Max or Ultra sign-in, or an Anthropic API key | Yes: cloud sessions keep running after you close your laptop (paid plans, claude.ai sign-in) |
| Cursor | AI code editor with Cloud Agents and a CLI | Free; Plus $8 (Grok models only); Premium $30; Super $100; Ultra $200 a month | A Cursor or X Subscription plan; your own OpenAI, Anthropic, Google, Azure or Bedrock key for chat models | Yes: Cloud Agents, on Premium and higher |
| GitHub Copilot | GitHub's coding assistant: IDE, Copilot CLI, Copilot app and cloud agent | Free; Pro $10; $39 plan; Max $100 a month; Business $19 per seat | A Copilot plan, billed in AI credits; Copilot CLI also takes your own provider keys | Yes: cloud agent; sessions on GitHub Actions run at most 59 minutes |
| Devin | Cognition's AI software engineer: Devin Desktop and Devin Cloud | Free; Pro $20; Max $200 a month; Teams $80 a month plus $40 per seat | A Devin plan | Yes: Devin Cloud, on Pro and higher |
| Jules | Google's experimental asynchronous coding agent for GitHub repositories | 15 tasks a day free; 100 with Google AI Pro; 300 with Google AI Ultra | A Google account; Google AI Pro or Ultra for more tasks | Yes: runs in a cloud VM you can leave |
| opencode | Open-source (MIT) coding agent for the terminal, desktop and IDE | Free; optional OpenCode Go $10 or Go Plus $40 a month | ChatGPT Plus/Pro, GitHub Copilot or GitLab Duo sign-in, or API keys for 75+ providers (Claude by API key only) | No hosted runner documented; runs on your computer |
| Aider | Open-source (Apache-2.0) AI pair programmer in your terminal | Free; you pay your model provider | API keys for OpenAI, Anthropic, Gemini, xAI, DeepSeek, OpenRouter and others, local models, or a GitHub Copilot sign-in | No: runs on your computer |
| Reason | Always-on teammate and coding agent: its own cloud computer per Session, memory, Loops and Slack | Pro $50 and Max $200 a month; no free plan | ChatGPT, Claude, SuperGrok or X Premium+ and GitHub Copilot sign-ins, or your own API keys | Yes: Sessions run on Reason's cloud computers with your laptop closed |
Prices and plans from each vendor's official pricing page or docs, checked Nov 5, 2026; US list prices. Sources are listed at the end of the page.
Try a Codex alternative on a real task in Reason
Open Reason on the web or the Mac app
Sign in at reasonmachines.com, or download the Reason app for macOS from reasonmachines.com/download. Both open the same Sessions. Sending work to Reason needs a Pro or Max plan.
Connect the plans you already pay for
In Settings › Models, connect subscriptions such as Claude (Pro or Max), ChatGPT (Plus, Pro or Business), Grok (SuperGrok or X Premium+) or GitHub Copilot, or add API keys. Reason runs on your own accounts first; a Reason plan's credits cover the rest.
Give it a task you know the answer to
In the composer, name the repository and paste a task you've already solved, such as a failing test. Reason works on its own cloud computer, runs the tests and opens a pull request, so you can compare its diff with your other agent's.
Switch the model and compare
Start a second Session on the same branch with a model from another provider, and ask it to review the first diff. Each Session shows the model and account it ran on.
Codex alternatives at a glance
| Made by | Open source | Where it runs | Price | |
|---|---|---|---|---|
| Claude Code | Anthropic | Not open source | Terminal, IDE, desktop, web; cloud sessions keep running with the laptop closed | Claude Pro $20, Max $100, Ultra $200 a month |
| Cursor | Anysphere | Not open source | AI code editor; Cloud Agents run in cloud VMs, from the editor, web, iOS or Slack | Free; Plus $8 (Grok models only); Premium $30; Super $100; Ultra $200 a month |
| Devin | Cognition | Not open source | Cloud workspace with shell, IDE and browser; CLI, desktop; Slack and Teams | Free; Pro $20; Max $200 a month; Teams $80 a month plus $40 per seat |
| GitHub Copilot cloud agent | GitHub | Not open source | Works in the background in a cloud environment; sessions on Actions run at most 59 minutes | Copilot paid plans from $10 to $100 a month; Business $19 per seat |
| Jules | Not open source | Experimental; runs tasks in a cloud VM | 15 tasks a day free; more with Google AI Pro and Ultra | |
| opencode | The opencode project | MIT | Terminal, desktop and IDE; 75+ providers and local models | Free; optional OpenCode Go from $10 a month |
| Aider | Aider-AI (GitHub) | Apache-2.0 | Pair programming in your terminal; almost any LLM, local ones included | Free; you pay your model provider |
| Reason | Reason Machines | Not open source | Web, Mac and iOS apps, Slack, command line; its own cloud computer per Session, or yours | Pro $50, Max $200 a month; credits |
From each vendor's own pages, checked Nov 2, 2026; prices are US list prices. For reference, Codex itself is included in ChatGPT Free and Go, Plus is $20 a month, and its CLI is open source under Apache-2.0.
Which alternative for which reason
Stronger benchmark scores: Claude Code. On Artificial Analysis's Coding Agent Index v2.0 (October 2026: FrontierCode v1.1, Terminal-Bench 4.0 and SWE-Atlas-QnA-AA), Claude Code on Opus 5.5 scores 62, Codex on GPT-6 Astra 55 and Grok Build on Grok 4.7 47, as listed on its comparison pages, checked Nov 2, 2026. Scores measure a harness and model together; try the same task in each on your own repository.
An editor instead of a terminal: Cursor. A teammate you tag in Slack that works in its own cloud workspace: Devin, or Reason. Already pay for GitHub: Copilot's cloud agent. Free and open source with any model, local ones included: opencode or Aider.
What people on Reddit say
Two Reddit threads on the same question, read in full:
In a small r/GithubCopilot thread from June 2026 (18 replies) asking which assistant developers actually use, the top reply likes both Claude Code and Codex, several say they moved to Codex for its limits, a few call Cursor the default answer, and several use Copilot because it's the tool their employer approves. Others mention opencode with DeepSeek and Antigravity for lower cost.
In an r/LocalLLaMA thread from April 2026 (over 150 replies) asking for a Claude Code-style agent for local models, many replies recommend opencode as the most plug-and-play option, several prefer pi for its small system prompt on consumer hardware, and others suggest Cline, Kilo Code or Roo Code in VS Code. A few point out that Claude Code itself can talk to a local model once its base URL is set.
Reason: all your AI subscriptions in one coding agent
Use the subscriptions you already pay for (ChatGPT, Claude, SuperGrok/X Premium+, Copilot) or your own API keys in one coding agent. Hit your limit and Reason keeps going on your other connected accounts or Reason credits.
Reason is an always-on teammate that is also a coding agent: its own cloud computer per Session, memory across Sessions, Loops and Slack, with the model picked per task. Work that runs on your own subscription or API key is billed by that provider and keeps its limits; Reason's plans are Pro at $50 and Max at $200 a month, with no free plan, and it isn't open source.
On cost: in Reason's published benchmark on GPT-6 Astra at xhigh effort, with the same tasks and graders, Reason 1.1 scored 65.1 against Codex's 62.5 on Coding Agent Index v1.5, at 22% lower cost per solved task. That's Reason's benchmark of its own harness, with the runner published to reproduce it.
Sources (checked Nov 2, 2026; table and FAQs checked Nov 5, 2026)
- OpenAI: Codex pricing
- openai/codex on GitHub (Apache-2.0)
- Anthropic: Claude plans and pricing
- Cursor: pricing
- Cursor docs: Cloud Agents
- Devin: pricing
- GitHub Docs: Copilot plans
- GitHub Docs: about Copilot cloud agent
- Jules docs: usage limits
- anomalyco/opencode on GitHub (MIT)
- Aider-AI/aider on GitHub (Apache-2.0)
- Artificial Analysis: Claude Code vs Codex
- Reason: Reason 1.1 Coding Agent Index results (Oct 10, 2026)
- Reason docs: plans
- Anthropic: what is the Ultra plan?
- Claude Code docs: Claude Code on the web
- Cursor docs: API keys
- OpenCode Go
- opencode docs: providers
- Aider docs: connecting to LLMs
- Aider docs: GitHub Copilot
- r/GithubCopilot: Which AI coding assistant are developers actually using in 2026? (Jun 2026)
- r/LocalLLaMA: What is the best coding agent (CLI) like Claude Code for local development? (Apr 2026)
Questions
What is the best alternative to Codex?
For coding quality on public benchmarks, Claude Code: on Artificial Analysis's Coding Agent Index v2.0 it scores 62 on Opus 5.5 against Codex's 55 on GPT-6 Astra. For an editor, Cursor; for a free open-source tool, opencode or Aider.
Is there a free open-source Codex alternative?
Yes. opencode (MIT) and Aider (Apache-2.0) are free and work with almost any model provider or a local model. Codex's own CLI is also open source under Apache-2.0.
Is Claude Code better than Codex?
On Artificial Analysis's Coding Agent Index v2.0, Claude Code on Opus 5.5 scores 62 and Codex on GPT-6 Astra 55. Codex is cheaper to start, since ChatGPT Free and Go include it.
Can I keep using my ChatGPT plan in another agent?
In Reason, yes: Settings › Models has Sign in with ChatGPT for Plus, Pro and Business plans. opencode also supports ChatGPT Plus. That plan's own limits still apply.
What happens when an agent hits its usage limit?
Claude Code, Codex and Cursor stop or offer paid usage at their plan's limits. Hit your limit? Reason keeps going on your other connected accounts or Reason credits.
Is Reason affiliated with these vendors?
No. Reason is built by Reason Machines and is not affiliated with or endorsed by Anthropic, OpenAI, Anysphere, Cognition, GitHub, Google or xAI. Facts about their products come from their own pages, linked under Sources.
Is Codex free?
Partly. ChatGPT Free and Go ($8 a month) include limited Codex in the desktop app; the CLI, IDE extension, web and iOS start with Plus at $20.
How much does Codex cost?
It comes with ChatGPT: Plus $20 a month, Pro $100, $200 or $500, and Business $20 per user billed annually ($25 monthly). With an API key you pay per token, without the cloud features.
Can I use Codex with my Copilot plan?
Yes, on GitHub: the OpenAI Codex coding agent runs on a Copilot subscription (public preview), and the Codex extension for VS Code has Sign in with Copilot on Copilot's $39 and Max plans.