GPT-5.1 vs GPT-5.2 Codex
Compare pricing, context windows, and strengths for GPT-5.1 by OpenAI and GPT-5.2 Codex by OpenAI - and see how to put either to work in Appaca.
GPT-5.1
Flagship model for coding, reasoning, and agentic tasks with adjustable reasoning depth and multimodal input/output.
View GPT-5.1GPT-5.2 Codex
Highly capable coding model optimized for long-horizon, agentic coding tasks with configurable reasoning and strong codebase awareness.
View GPT-5.2 CodexGPT-5.1 vs GPT-5.2 Codex at a glance
Specs and pricing side by side, from the Appaca AI models directory.
| Spec | GPT-5.1 | GPT-5.2 Codex |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Model type | Text | Text |
| Context window | 400K tokens | 400K tokens |
| Input price | $1.25 / 1M tokens | $1.75 / 1M tokens |
| Output price | $10 / 1M tokens | $14 / 1M tokens |
| Status | Current | Superseded by GPT-5.3 Codex |
How GPT-5.1 and GPT-5.2 Codex differ
What the numbers mean in practice when choosing between GPT-5.1 and GPT-5.2 Codex.
-
GPT-5.1 is 29% cheaper on input tokens ($1.25 vs $1.75 per million), which adds up quickly in document-heavy workloads.
-
GPT-5.1 is 29% cheaper on output tokens ($10 vs $14 per million) - the bigger factor for tools that generate long documents.
-
Both models offer the same 400K tokens context window.
-
GPT-5.2 Codex has been superseded by GPT-5.3 Codex - for new builds, consider the newer model first.
Strengths side by side
Where each model shines, according to benchmarks and provider positioning.
GPT-5.1
1. Configurable Reasoning for Agentic Tasks
- Built to excel in autonomous or semi-autonomous coding workflows, with adjustable reasoning effort for planning, refactoring and debugging.
2. Fast Multi-Modal Input with Large Output
- Accepts both text and image inputs while producing text outputs.
- Offers up to 128 k output tokens, allowing long responses and code generation across multiple files.
3. Large Context & Knowledge Cut-Off
- 400 k token context window supports processing large codebases or documents.
- Knowledge cut-off of Sep 30 2024 ensures familiarity with recent tools and frameworks.
4. Reasoning Token Support
- Provides explicit support for reasoning tokens, enabling developers to fine-tune the balance between reasoning depth and speed.
GPT-5.2 Codex
1. Optimized for Long-Horizon Coding Tasks
- OpenAI describes GPT-5.2 Codex as a highly intelligent coding model built for long-horizon, agentic coding work.
- Well suited to planning, refactoring, debugging, and multi-step implementation flows inside real codebases.
2. Adjustable Reasoning for Coding Work
- Supports configurable reasoning effort from low to xhigh depending on speed and quality needs.
- Accepts both text and image inputs while producing text output.
3. Large Context + Long Output
- 400 k token context window supports broad repository understanding and larger working sets.
- Allows up to 128 k output tokens for longer patches, code generation, and technical explanations.
4. Up-to-Date Model Snapshot
- Knowledge cut-off of Aug 31 2025 keeps it current with newer tools and frameworks.
- Supports streaming, function calling, and structured outputs for tool-driven coding workflows.
Use GPT-5.1 or GPT-5.2 Codex - or both
Appaca is the AI workspace for operators. Build internal tools and AI co-workers powered by GPT-5.1 or GPT-5.2 Codex - connected to your real data and ready for your whole team. No code, no deployment.
Describe it, and it's built
Tell the Appaca agent the internal tool you need and it builds a working app powered by GPT-5.1 or GPT-5.2 Codex. No code, no API keys, no deployment.
Switch models without rebuilding
Start on GPT-5.1, test the same tool on GPT-5.2 Codex, and keep whichever performs better - the rest of your app stays exactly as it is.
Automated for the whole team
Schedule tools to run on autopilot - daily digests, weekly reports, real-time triggers - and share them with your whole team from one workspace.
Describe it, and it's built
Tell the Appaca agent what your team needs and it builds a working app powered by GPT-5.1 or GPT-5.2 Codex - connected to the tools you already use.
Related comparisons
See how GPT-5.1 and GPT-5.2 Codex stack up against other models in the directory.
FAQs
GPT-5.1 is generally cheaper: $1.25 input / $10 output per million tokens, versus $1.75 / $14 for GPT-5.2 Codex. Actual cost depends on how many tokens your workload reads and writes.
They are equal: both GPT-5.1 and GPT-5.2 Codex support a 400K tokens context window.
It depends on the job. Compare the pricing, context window, and strengths above against your workload - and remember the choice isn't permanent. In Appaca you can build a tool on GPT-5.1, test the same tool on GPT-5.2 Codex, and switch at any time without rebuilding anything.
Yes. Appaca is a no-code AI workspace: describe the internal tool your team needs and the Appaca agent builds it as a working app powered by GPT-5.1, GPT-5.2 Codex, or any other model in the directory - with a built-in database, team access, and integrations. No API keys to wire up and nothing to deploy.
Build AI tools with GPT-5.1 or GPT-5.2 Codex
Describe the tool your team needs and get a working app powered by the model you choose - with a built-in database, team access, and integrations. No code, no deployment.