OpenAI Codex · AI Software Engineer

    The AI developer that actually does the work.

    OpenAI Codex is a cloud-based AI software engineer. It reads your codebase, writes features, fixes bugs, creates tests — asynchronously, while you keep working.

    Powered by codex-1 (optimised o3). Native GitHub integration. Isolated sandbox. No copy-paste.

    10×
    Faster on routine tasks
    Features, tests, refactoring
    24/7
    Autonomous execution
    Works while you sleep
    Parallel tasks
    No bottleneck from waiting
    0
    Context switches
    You review, not implement

    What is OpenAI Codex?

    OpenAI Codex is a cloud-based AI software engineer running on codex-1 (optimised o3). It reads your entire codebase, writes features, fixes bugs, creates tests and opens pull requests — asynchronously, without a developer having to supervise every step. Native GitHub integration and an isolated sandbox allow parallel tasks without interference. For Swiss organisations, Codex can be deployed via Azure OpenAI with data residency in Switzerland or the EU.

    200M+

    ChatGPT users worldwide

    OpenAI 2025
    92%

    of Fortune 500 use OpenAI

    OpenAI 2025
    10×

    faster feature development with Codex

    OpenAI 2025
    1M+

    developers linked via GitHub Codespaces

    GitHub 2025

    Codex is not autocomplete — it is an autonomous developer that opens pull requests in the background while your team works on the next feature. That changes how we scale projects.

    Marcel HaasCEO, CNEXT

    What is Codex?

    Not just code autocomplete.

    OpenAI Codex (2025) is not an autocomplete tool like GitHub Copilot. It is a fully autonomous software engineering agent — with its own sandbox environment, real codebase understanding, and the ability to complete multi-step tasks asynchronously.

    You delegate a task. Codex clones your repo, analyses the relevant code, implements the solution, runs tests, iterates on failures — and opens a PR for review. All without your involvement.

    Powered by codex-1 (o3-optimised)Native GitHub integrationIsolated sandboxAsync & parallelFull PR workflow
    What Codex does

    Every engineering task that costs you time.

    Write features

    Describe the requirement. Codex reads your codebase, plans the changes, implements them and opens a PR.

    Fix bugs

    Point Codex at the failing test or stack trace — it finds the root cause, corrects it and writes a regression test.

    Write tests

    Generates unit, integration and end-to-end tests for existing code. Runs them directly and fixes failures.

    Refactor code

    Renames variables, extracts components, modernises APIs — across multiple files in one step.

    Review code

    Analyses PRs for bugs, security gaps, performance issues and style violations with precise improvement suggestions.

    Write docs

    Generates README files, API docs, inline comments and changelogs directly from source code.

    How it works

    From task to merge — without your involvement.

    01

    Hand off the task

    You describe the task in natural language — in ChatGPT, via API or directly in the terminal.

    02

    Codex analyses your repo

    Codex clones your GitHub repo into an isolated sandbox, reads relevant files and plans the changes.

    03

    Execution & testing

    Writes code, runs tests, iterates on failures — fully autonomously and asynchronously in the background.

    04

    PR ready for review

    Opens a pull request with full reasoning. You review, comment or merge — you stay in control.

    Comparison

    Codex vs. chat-based AI tools.

    FeatureOpenAI CodexChatGPT / Copilot / Cursor
    Execution mode
    Asynchronous, cloud-based — runs in the background while you keep working
    Synchronous in chat — you wait for each response
    Codebase context
    Reads and understands your entire repo — structure, dependencies, tests
    Only what you manually paste in
    Execution
    Runs code, tests and build commands in an isolated sandbox
    Generates code but does not run it
    GitHub integration
    Native: clones repos, opens PRs, works with branches
    Manual copy-paste workflow
    Parallel tasks
    Multiple tasks simultaneously — like a team of developers
    One conversation at a time
    CNEXT services

    We integrate Codex into your team.

    From the first repo connection to fully automated dev pipelines.

    Codex onboarding & setup

    We connect your GitHub repos to Codex, configure permissions, sandbox rules and CI/CD hooks — production-ready in a day.

    Team enablement

    Workshops on effective task formulation, prompt libraries for your tech stack and internal playbooks.

    API integration

    Trigger Codex tasks directly from your tools — Jira, Linear, Slack, custom systems — via the OpenAI Responses API.

    Enterprise security

    Sandbox isolation, secret management, audit logs. Optionally via Azure OpenAI for Swiss data residency.

    Multi-agent pipelines

    Combine Codex with our OpenClaw agents for fully automated dev-to-deploy pipelines.

    Governance & compliance

    Code review policies, branch protection rules, FADP/GDPR-compliant configuration for Swiss enterprises.

    Codex + OpenClaw + Claude = full agentic pipeline

    Combine Codex with our OpenClaw agents and Anthropic Claude for end-to-end automated development and business processes.

    Go to Agentic AI

    Ready to launch your first Codex project?

    We connect your repos, train your team and make sure Codex is productive from day one.