Claude Code vs OpenAI Codex

Best for

• Multi-file refactors
• Migrations
• Delegated engineering tasks

Watch out

Claude Code is included with Pro, Max, Team and Enterprise; Free does not include it. Web prices: Pro $20/month or $200 billed yearly; Max 5x $100/month and Max 20x $200/month; Team Standard $25/seat/month or $20 with annual billing, Premium $125 or $100 respectively; Enterprise $20/seat/month with annual billing plus API-rate usage (https://claude.com/pricing). API credentials can bill separately from subscription usage. Model selection depends on account, user/org settings, provider and client version: default clears an override, while Anthropic API opus and sonnet resolve to Opus 5.5 and Sonnet 5.5. Sonnet 5.5 requires v2.1.284+, Opus 5.5 v2.1.280+. Third-party provider aliases can resolve to older versions. Fable normally resolves to Fable 5.1, except Claude apps gateway sessions use Fable 5; neither is an account-type default. On Pro, Fable uses usage credits; on Max it can use up to 50% of the regular weekly allowance before additional Fable work requires usage credits. Interactive credit consent is not a guarantee for automation: non-interactive -p requests can bill credits without asking. Five-hour and weekly limits depend on plan/model; check the account usage page (https://code.claude.com/docs/en/model-config; https://support.claude.com/en/articles/11049741-what-is-the-max-plan). Native Windows supports shell tools, but Claude's sandbox is available on macOS, Linux and WSL2, not native Windows or WSL1. It is off by default and covers shell execution, not every file tool, MCP server or hook (https://code.claude.com/docs/en/sandboxing).

Best for

• Delegated coding tasks
• Existing OpenAI commitments

Watch out

ChatGPT sign-in uses Codex plan credits, whose rates differ from API prices. Do not estimate subscription task allowances from Platform token tariffs. Standard GPT-6.1 Sol rates are 50 input / 2.5 cached input / 250 output credits per million tokens; no separate cache-write charge. Plus is $20/month; Pro tiers are $100/$200/$500; Business Standard is $20/user/month with annual billing (two-user minimum), $25 monthly; Enterprise is negotiated. Pro has no five-hour limit, while Plus/Standard Business local-message estimates are not fixed caps; weekly limits and shared Work/Codex usage still apply. Fast mode bills at 2.5x included subscription credits or 2x purchased/pay-as-you-go credits; Astra Ultrafast is 8x or 6x respectively and requires eligible access such as Pro 500. These are billing multipliers, not speed guarantees (https://learn.chatgpt.com/docs/pricing; https://learn.chatgpt.com/codex/agent-configuration/speed). GPT-6.1 Sol access is rolling out on Plus/Pro/Business/Enterprise/Edu; Enterprise/Edu admins must enable it. Free/Go desktop Luna access is rollout-dependent. Model availability varies by account, surface and client version (https://learn.chatgpt.com/docs/models). API-key sign-in supports local desktop/CLI/IDE work and uses Platform billing; cloud features such as GitHub review and Slack require ChatGPT sign-in (https://learn.chatgpt.com/docs/auth). GPT-5.4/mini retired from ChatGPT-authenticated Codex on August 31; GPT-5.5 retirement is scheduled for October 14, 2026, with API availability unaffected. Pick a currently supported Sol/Luna replacement. Linux/WSL2 uses bubblewrap with a user-namespace-dependent bundled fallback; native Windows has its own sandbox and WSL1 is unsupported from CLI v0.115.0 (https://learn.chatgpt.com/docs/sandboxing).