AI coding assistants
Codex: review, pricing, data and alternatives
Codex lets people developing software write and edit code, fix errors, run commands and tests, and review repository changes. It also supports background development tasks and programming agent integration into workflows. A free tier exists; the first paid plan costs $8 per month. Access and transparency score: 90/100, #1 of 31 in its category.
What is Codex?
Codex lets people developing software write and edit code, fix errors, run commands and tests, and review repository changes. It also supports background development tasks and programming agent integration into workflows.
According to its documentation, Codex lets you:
- write and edit code files
- find and fix errors
- run commands and tests
- review changes in a repository
- perform development tasks in the background
- integrate a programming agent into a workflow
We file it under AI coding assistants, the category of tools to write and fix code, and it also overlaps with aI agent builders and developer tools. The category lists 31 verified tools on this site.
The publisher is OpenAI OpCo, LLC, based in United States. The service launched in 2025.
Who is it for?
It is mostly useful to these profiles: developers. The need it covers is simple to state: write and fix code.
Codex is a good candidate if:
- you want to try before paying
- you plan to connect it to your tools or automations through its API
- you also work from your phone
- you want to read the code or host it yourself
Before deciding, run a trial on a real task and measure the time saved: it is the only criterion that really counts.
How much does Codex cost?
Pricing model: freemium (limited free use, then paid). A free plan is offered, usually limited in volume or features.
The first paid plan costs $8 per month (ChatGPT Go, limited access to Codex in the desktop app, depending on rollout. Plus at USD 20/month provides access to cloud, CLI, and IDE extension features, among others), according to the pricing page, checked on October 24, 2026.
Per month, that is cheaper than the category median ($15 per month, based on tools with a published price).
To estimate what the same work would cost done directly with an AI model, use our API price calculator. Prices change often: always check the official site before subscribing.
Data and privacy
According to its privacy policy, data is processed in several regions depending on the plan.
Exporting your content: yes (details on the official site). Being able to get your data back makes switching tools easier later.
Three habits apply to every AI tool:
- turn off the use of your content for training if the option exists
- use a work account separate from your personal account
- review everything the tool produces before publishing or sending it
Platforms, languages and API
Codex runs on: web browser, Windows, macOS, Linux, iPhone and iPad, browser extension, API, and Slack.
Interface languages: English.
A public API lets you call it from your own programs or an automation tool, and plug it into an AI agent.
The source code is public: openaiopenai/codex.
How we scored it
Our 90/100 score does not judge output quality: it measures what can be publicly verified about access to the tool, its openness and how far the publisher can be trusted.
| Criterion | Points | What counts |
|---|---|---|
| Access | 25/30 | free tier, published price, French interface |
| Openness | 30/30 | API, data export, open code |
| Trust | 35/40 | identified publisher, declared hosting, age, presence in reference lists |
The full calculation is explained on our method page.
Comparison with alternatives
Codex against other tools in the aI coding assistants category:
| Tool | Free | Entry price | API | Score |
|---|---|---|---|---|
| Codex | Yes | $8 per month | Yes | 90 |
| aider | Yes | not published | Yes | 78 |
| Kilo | Yes | $15 per month | Yes | 78 |
| GitHub Copilot | Yes | $10 per month | Yes | 75 |
| Amazon Q Developer | Yes | $19 per month | – | 71 |
| OpenCode | Yes | $10 per month | Yes | 71 |
| Amp | Yes | $20 per month | Yes | 70 |
| Continue | Yes | not published | – | 68 |
Verdict
Codex is among the most accessible and transparent tools in its category.
Strengths
- Free tier to try it
- Cheaper than its category median
- Public API
- Public source code
- Available on many platforms
Alternatives
- aiderfree tier
- Kilofree tier
- GitHub Copilotfree tier
- Amazon Q Developerfree tier
- OpenCodefree tier
- Ampfree tier
Categories and jobs
Learn more
Frequently asked questions
Is Codex free?
Yes, a free plan exists, with usage limits. The first paid plan costs $8 per month.
Where is Codex data stored?
According to the publisher, in several regions depending on the plan.
Does Codex have an API?
Yes, a public API is documented.
What are the alternatives to Codex?
In the same category: aider, Kilo, GitHub Copilot, and Amazon Q Developer.
Codex or aider: which one to choose?
Our score is 90/100 for Codex and 78/100 for aider. Try both on the same task before paying.
Related articles
- Creating videos with AI: what works todayOctober 10, 2026
- Generating images with AI: tools, pricing, and limitationsOctober 9, 2026
- How to use NotebookLM: a complete guideOctober 8, 2026
- Free ChatGPT alternatives: what they actually offerOctober 7, 2026
Neutrality. No affiliate links. No vendor pays to be reviewed, rated or ranked. Reviews are directed by François Chollet, neutral and factual, and every data point is dated and sourced. How we score