Codex: pricing, limits, errors and comparisons
Codex is OpenAI's coding agent, used from the CLI, IDE extensions, the desktop app and ChatGPT.
21 articles · last updated Oct 2, 2026
Free tiers and limits
- Codex 429 After Retries: Find the Limit That Owns the Request
The message says Codex exhausted its automatic retries after repeated 429 responses. It does not identify the quota owner, so recover by finding the active route before retrying again.
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- Are Codex Limits Shared Across Accounts? Check the Account, Workspace, API, and Device Meters
Separate normal Codex usage sharing from same-machine account-switching symptoms with a meter board, evidence checklist, and safe continuation choices.
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Errors and fixes
- Codex Keeps Reconnecting? Find the Cause Without Losing Your Task
Five reconnect attempts do not identify the cause. Save the prompt and changed-file state first, then use one new task, one basic command, and one controlled network comparison to narrow the failure.
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- Codex Timed Out Loading the Cloud Config Bundle: Diagnose the Startup Boundary
This 15-second error happens before a normal model turn: Codex could not complete managed-configuration loading without a valid identity-matched cache. Preserve that state, then test one boundary.
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- Codex Remote Compact Failed: Read the Suffix Before You Retry
The wrapper tells you that conversation compaction failed. The text after it tells you whether to inspect the stream, route, parameter, context, policy, parser, or child process.
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Comparisons and alternatives
- Codex Plus vs Pro 5x vs Pro 20x: Pay for the Limit You Actually Need
Plus is the sensible default, Pro 5x buys sustained headroom, and Pro 20x is for people who can prove they will use it. The old 10x label was a temporary promotion, not today's third plan.
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- Claude Code vs Codex in 2026: Which Coding Agent Should You Use Now?
Claude Code still fits supervised local coding best; Codex fits delegated multi-surface engineering work. The practical choice depends on where the job should run and who owns review.
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- GPT-5.4 mini vs GPT-5.3-Codex: Which Model Should You Use?
GPT-5.4 mini is the better default for new API and subagent work, but GPT-5.3-Codex still has a real place in terminal-heavy coding and Codex cloud-task workflows. This guide explains exactly when to choose each.
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- GPT-5.4 vs GPT-5.3-Codex: Which Should You Use in 2026?
GPT-5.4 is the stronger default model for most serious coding and agentic work in March 2026, but GPT-5.3-Codex still has a narrower case around terminal-first work and lower input costs. This guide explains exactly when to choose each.
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- Gemini 3.1 Pro vs Opus 4.6 vs Codex 5.3: The Definitive Comparison (March 2026)
Three frontier models released in February 2026 have fundamentally changed the AI landscape. This guide compares Gemini 3.1 Pro, Claude Opus 4.6, and GPT-5.3-Codex with browser-verified pricing, real benchmark data, and practical recommendations for developers choosing their next production model.
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- GPT-5.3 Codex vs Claude Opus 4.6: The Complete Comparison Guide (2026)
GPT-5.3 Codex and Claude Opus 4.6 launched within 24 hours of each other in February 2026. This guide uses verified benchmark data, real pricing analysis, and scenario-based recommendations to help you choose the right model — or decide to use both.
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- GPT 5.2 Codex vs Claude Opus 4.5: Complete Comparison Guide (2026)
Compare OpenAI GPT 5.2 Codex and Anthropic Claude Opus 4.5 head-to-head with January 2026 benchmarks, real-world speed tests, pricing analysis, and clear recommendations for developers.
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Guides and setup
- Codex self signed certificate in certificate chain: 4 Fixes
The certificate is almost always your company's root CA. Codex's client, the desktop app, MCP servers and sandboxed commands each read a different setting.
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- How to Generate and Edit Images in Codex with GPT Image 2
Ask Codex for the image you need, refine it with a reference, and bring the saved result into your project. The key is to request an actual generated file and keep image usage separate from API billing.
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- Codex Token Exchange Failed: Diagnose the Login Phase Before You Reset It
A successful browser screen does not prove the Codex process received a token. Identify exchange, callback, or refresh failure first, then repair the right host.
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- Connect Codex to a Third-Party Model API Without Guessing the Protocol
An OpenAI-compatible label is not enough: Codex needs a Responses-compatible route, a real provider model ID, working streaming, and credentials owned by the same route.
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- Does Codex Require a Phone Number to Sign In?
A phone number is not universal for Codex, but an official ChatGPT sign-in can still redirect some accounts to add-phone. The screen you see determines whether you can continue, change auth routes, or need OpenAI Support.
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- Codex Subagents: A Practical Guide to Delegation That Holds Up
Subagents work best when the branches are genuinely independent, the return contract is explicit, and one main thread still owns the final decision.
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- Codex Sandbox and config.toml: Permissions Without Full Access
The sandbox controls where commands can act; approvals control when Codex must stop and ask. Diagnose that boundary before granting broader host access.
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- ChatGPT Go Codex Usage Explained: What You Get, Limits, and Upgrade Paths
ChatGPT Go includes limited Codex access, but the dashboard matters more than old quota tables. Check your meter, then choose Go, Plus/Pro, or API-key local usage by workload.
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- Azure OpenAI for Codex: Setup Route, Surface Limits, and Troubleshooting
Codex can run through an Azure OpenAI provider route for CLI, IDE, and automation work, but deployment names, env vars, Entra ID, direct OpenAI API-key usage, and Codex cloud features are separate decisions.
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