GPT-5.1 Codex mini vs GPT-5-Codex
Benchmarks, API Token Pricing, Context Window & Speed Comparison
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GPT-5.1 Codex mini by OpenAI and GPT-5-Codex by OpenAI represent two of the frontier AI models analyzed in our comprehensive 2026 AI benchmark and LLM comparison. In this head-to-head evaluation, we examine API token pricing, context window specifications, inference speed (tokens per second), and empirical reasoning performance. From a pure economic perspective, GPT-5.1 Codex mini holds a notable pricing advantage for token ingestion. On output generation, GPT-5.1 Codex mini is more economical per million generated tokens. In data-heavy architectures requiring extensive repository or document analysis, both models provide an identical memory horizon with 400K tokens. In latency-sensitive production environments, GPT-5.1 Codex mini leads in tokens-per-second throughput, making it ideal for real-time conversational agents and high-concurrency workflows. Below is the complete empirical head-to-head breakdown across cost, speed, context, and capability matrices.
Changez et Comparez les Modèles
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GPT-5.1 Codex mini
Codex compactun cheap codage-optimised Codex lane pour rapide edits et revue à échelle.
$0.25 / 1M
$2.00 / 1M
400K tokens
55.5%
GPT-5-Codex
Spécialiste du codageUne variante de GPT-5 optimisée pour les modifications de dépôts, la revue de code et le travail logiciel agentique.
$1.25 / 1M
$10.00 / 1M
400K tokens
74.5%
Différences Clés en un Coup d’Œil
- GPT-5.1 Codex mini is 5.0x cheaper for API usage (input + output tokens combined).
- GPT-5.1 Codex mini is faster at 180 tok/s vs 120 tok/s.
- GPT-5-Codex leads on SWE-bench coding (74.5% vs 55.5%).
| Caractéristique | GPT-5.1 Codex mini | GPT-5-Codex |
|---|---|---|
Intelligence Index Composite reasoning & knowledge score (0-100) | 47 | 57 |
Provider | OpenAI | OpenAI |
Input Price Cost per million input tokens | $0.25 / 1M | $1.25 / 1M |
Output Price Cost per million output tokens | $2.00 / 1M | $10.00 / 1M |
Blended Price Weighted 7:2:1 cache:input:output per 1M | $0.27 / 1M | $1.34 / 1M |
Context Window Maximum input + output tokens | 400K tokens~600 A4 pages of text | 400K tokens~600 A4 pages of text |
Max Output Tokens Per single request | 128K | 128K |
Throughput Speed Tokens generated per second | 180 tok/s | 120 tok/s |
SWE-bench Verified Real-world software engineering | 55.5% | 74.5% |
GPQA Diamond Graduate-level reasoning | 66.5% | 80.5% |
Cached Input Price Prompt caching discount per 1M tokens | $0.03 / 1M | $0.13 / 1M |
Qui gagne où ?
At-a-glance decision frameworkScores de Benchmarks Vérifiés
Official evaluation metrics verified by independent third-party research labs.
Industry benchmark evaluating real-world GitHub issue resolution and multi-file debugging.
Challenging questions created by domain experts to test complex PhD-level reasoning.
Hardened reasoning and academic knowledge benchmark with reduced lucky-guess probability.
Crowdsourced human preference evaluation based on blind, head-to-head model battles.
Extremely difficult, closed-ended questions spanning the frontier of human expert knowledge.
Autonomous multi-step tasks executed inside a real command-line terminal environment.
Research-grade coding problems drawn from real scientific and numerical workloads.
Contamination-free competitive programming problems collected continuously over time.
American Invitational Mathematics Examination — multi-step Olympiad-level reasoning.
Accuracy when reasoning over very large inputs that fill the model context window.
Tokens emitted per second during active generation streaming.
Latence et Temps de Réponse
Time to first token (TTFT) and estimated end-to-end response time for a typical 500-token response.
Simulateur Interactif de Coût de Tokens
Adjust sliders to calculate projected monthly cloud API spending with prompt caching discounts.
GPT-5.1 Codex mini · Strengths & Key Advantages
- Cheap, rapide codage assistance
- bon pour lint fixes, refactors et revue comments
- Retains le 400K fenêtre de contexte
- excellent pour linting, formatage et petit refactors
Considerations & Trade-offs
- Struggles sur grand, interdependent repositories
- moins fiable que complet Codex sur multifichier refactors
GPT-5-Codex · Strengths & Key Advantages
- Codage agentique de premier ordre dans Codex et Copilot
- Conçu pour de longues sessions d'édition à l'échelle du dépôt
- Même tarification que GPT-5 malgré l'optimisation pour le code
- Excellent pour les réparations pilotées par les tests et le débogage itératif
Considerations & Trade-offs
- Moins naturel que GPT-5 en conversation générale
- Excessif pour les charges de travail hors code
Token Use & Task Economics
Estimated cost and token consumption to complete one representative agentic task.
| Metric | GPT-5.1 Codex mini | GPT-5-Codex |
|---|---|---|
Cost per Task Estimated USD to finish one task | $0.33 | $1.60 |
Output Tokens / Task Tokens generated per task | 48K | 58K |
Reasoning Tokens / Task Thinking tokens burned per task | 23K | 32K |
Spécifications Techniques
Architecture, release timeline, capabilities, and modalities.
| Caractéristique | GPT-5.1 Codex mini | GPT-5-Codex |
|---|---|---|
| Official API Model ID (SDK) | gpt-5-1-codex-mini | gpt-5-codex |
| API Protocol | OpenAI Responses API & Chat Completions v1 | OpenAI Responses API & Chat Completions v1 |
| Release Date | 2025-11 | 2025-09 |
| Knowledge Cutoff | October 2024 | September 2024 |
| Architecture | Compact code-specialised reasoning model | Code-specialised unified reasoning model |
| Parameters | Confidential | Confidential |
| Enterprise Rate Limits (RPM / TPM) | 10,000 – 30,000 RPM (Tier 5 Enterprise) · 800,000 – 2,000,000 TPM | 10,000 – 30,000 RPM (Tier 5 Enterprise) · 800,000 – 2,000,000 TPM |
| Long-Context Tier (>128K/200K) | Flat rate ($0.25/1M in) across full 400K window | Flat rate ($1.25/1M in) across full 400K window |
| Prompt Cache Policy & TTL | Automatic prefix caching at $0.025/1M (no extra cache-write fee) | Automatic prefix caching at $0.125/1M (no extra cache-write fee) |
| Computer Use / GUI Agent | Supported (Screen coordinate grounding, browser & desktop GUI action loops) | Supported (Screen coordinate grounding, browser & desktop GUI action loops) |
| MCP & Parallel Tool Calling | Native MCP Client/Server ready · Parallel function calling · 100% Strict JSON Schema | Native MCP Client/Server ready · Parallel function calling · 100% Strict JSON Schema |
| Web Search Grounding & Sandbox | Native Web Search tool + Hosted Code Interpreter & File Search RAG | Native Web Search tool + Hosted Code Interpreter & File Search RAG |
| Official Fine-Tuning Support | Supervised Fine-Tuning (SFT), Direct Preference (DPO) & Reinforcement Fine-Tuning (RFT) | Supervised Fine-Tuning (SFT), Direct Preference (DPO) & Reinforcement Fine-Tuning (RFT) |
| Multimodal Token Billing | Text BPE (~4 chars/token) · Vision (~258–765 tokens per image tile) | Text BPE (~4 chars/token) · Vision (~258–765 tokens per image tile) |
| Quantization & Min GPU VRAM | Cloud-Hosted Proprietary (FP8 / BF16 Tensor Core Cluster) · Zero Local VRAM Required (100% Serverless Cloud API) | Cloud-Hosted Proprietary (FP8 / BF16 Tensor Core Cluster) · Zero Local VRAM Required (100% Serverless Cloud API) |
| Safety & Frontier Classification | OpenAI Preparedness Framework Audited & System Card Published | OpenAI Preparedness Framework Audited & System Card Published |
| Enterprise Compliance (ZDR/HIPAA/SOC2) | SOC2 Type II · GDPR · Zero Data Retention (ZDR) & HIPAA BAA Available on Enterprise Tier | SOC2 Type II · GDPR · Zero Data Retention (ZDR) & HIPAA BAA Available on Enterprise Tier |
| Input Modalities | text, vision | text, vision |
| Output Modalities | text | text |
GPT-5.1 Codex mini vs GPT-5-Codex: Réponses Rapides (FAQ)
Which is more intelligent, GPT-5.1 Codex mini or GPT-5-Codex?
GPT-5-Codex is more intelligent. It scores 57 compared with 47 on the composite Intelligence Index.
Which model is faster?
GPT-5.1 Codex mini is faster, generating 180 tokens per second compared with 120 tokens per second.
Which model is cheaper to run?
GPT-5.1 Codex mini is cheaper at $0.27 per 1M tokens blended, compared with $1.34 (7:2:1 cache:input:output ratio).
Which model has lower latency?
GPT-5.1 Codex mini has lower latency, with a time to first token of 0.72s compared with 1.25s.
Verdict
Verdict & Model Selection Recommendation: Choose GPT-5.1 Codex mini if your priority is High-volume code automation and inline review. Its performance in demanding tasks justifies its operational token cost. Choose GPT-5-Codex if your workflow prioritizes Agentic coding assistants and automated code review. For large-scale batch processing or customer-facing conversational interfaces, its balance of speed and economics delivers superior ROI.
Questions fréquentes
How does GPT-5.1 Codex mini compare to GPT-5-Codex in API token pricing and cost per token?+
GPT-5.1 Codex mini costs $0.25 per 1M input tokens and $2.00 per 1M output tokens, whereas GPT-5-Codex costs $1.25 input and $10.00 output. Overall, GPT-5.1 Codex mini is the more cost-effective model for high-volume API pipelines. Both models support prompt caching discounts of up to 90% for repeated prompt prefixes.
Which model has a larger context window: GPT-5.1 Codex mini or GPT-5-Codex?+
Both GPT-5.1 Codex mini and GPT-5-Codex offer an identical context window of 400K tokens (~300k words). Both architectures provide equal capacity for large document ingestion, multi-file codebases, and extended multi-turn conversation histories.
Which AI model is better for software engineering and coding: GPT-5.1 Codex mini or GPT-5-Codex?+
GPT-5.1 Codex mini scores 55.5% on SWE-bench Verified while GPT-5-Codex scores 74.5%. For autonomous software engineering and multi-file debugging, GPT-5-Codex holds the verified benchmark lead.
What is the difference in reasoning capability and extended thinking between GPT-5.1 Codex mini and GPT-5-Codex?+
GPT-5.1 Codex mini features native chain-of-thought extended thinking mode with configurable reasoning effort. In contrast, GPT-5-Codex provides chain-of-thought reasoning depth for complex math and science.
How does inference speed (tokens per second) compare between GPT-5.1 Codex mini and GPT-5-Codex?+
GPT-5.1 Codex mini generates approximately 180 tokens per second, while GPT-5-Codex delivers 120 tokens per second. In latency-sensitive production environments, GPT-5.1 Codex mini provides faster time-to-first-token (TTFT) and higher streaming response velocity.
Can you implement a tiered LLM routing setup combining GPT-5.1 Codex mini and GPT-5-Codex to optimize costs?+
Yes! High-efficiency architectures route high-frequency routine classification and conversational tasks to GPT-5.1 Codex mini to save operational costs, and dynamically escalate complex architectural queries or reasoning tasks to GPT-5-Codex. This tiered routing pattern cuts overall API bills by up to 70%.
Understand key metrics like context window, token pricing, reasoning mode, and SWE-bench scores in our comprehensive AI glossary.
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Les scores de benchmarks, tarifs par token et limites évoluent rapidement. Vérifiez toujours les spécifications actuelles sur la documentation officielle du fournisseur.
Sources: GetInfoUs Independent AI Benchmarks & Official API Specs