Devin vs OpenAI Codex (2026)

Devin

by Cognition

OpenAI Codex

by OpenAI

Pros

• ✓Cognition states that 89% of code committed by its own engineers is committed by Devin, and names Citi, Mercedes-Benz, Goldman Sachs, Elevance, Dell, Santander and the U.S. Army and Navy among customers, which is unusually strong enterprise evidence for an autonomous agent.
• ✓Devin Desktop, formerly Windsurf, is bundled into every paid plan, so Pro at $20 per month covers both autonomous cloud sessions and agentic coding in a local IDE under one subscription rather than two.
• ✓MCP works in both directions. Cognition publishes an MCP server at mcp.devin.ai that external agents connect into to manage sessions, playbooks and schedules, and Devin consumes external servers through its MCP Marketplace.

Limitations

• ⚠Asynchronous operation creates a slow feedback loop. Tasks take minutes to hours rather than the near-instant responses developers expect in an editor, which rules Devin out for tight iteration, live debugging and pair programming.
• ⚠Cognition publishes no autonomous task-completion rate. Its 89% figure measures share of commits inside Cognition itself rather than the proportion of assigned tasks completed, and its own case-study language describes a human approving changes on large migrations.
• ⚠Usage past the included quota bills at API rates, so monthly spend is hard to predict for teams running several concurrent sessions, and Enterprise moves to Agent Compute Unit billing with no published rate.

Pros

• ✓One agent spans the ChatGPT desktop app, the open-source Codex CLI, IDE extensions for VS Code, Cursor and Windsurf, native Xcode and JetBrains integrations, and Codex cloud on the web and iOS.
• ✓Codex reviews GitHub pull requests and GitLab merge requests on request or automatically, and a GitHub Action, the Codex SDK and codex exec bring it into CI and scripted workflows.
• ✓Parallel tasks in separate worktrees, subagents, Skills, plugins, MCP servers and scheduled tasks let Codex take on longer and repeated work, with GPT-6 Sol and GPT-6 Luna on Plus and above.

Limitations

• ⚠Codex usage is metered against plan limits shared with ChatGPT Work, and the number of messages varies with the model, task size and context, so heavy users on Plus may need credits or a Pro plan.
• ⚠OpenAI removed the Codex MCP server on September 5, 2026, so other assistants can no longer call Codex over MCP, although Codex still connects out to external MCP servers.
• ⚠The Codex documentation covers GitHub and GitLab and does not mention Bitbucket, and Codex run with an API key excludes the cloud features such as GitHub code review and Slack.