Codex Mini vs Grok 4.1 Fast
Codex Mini vs Grok 4.1 Fast: Grok 4.1 Fast is cheaper for input-heavy usage ($0.20/M vs $1.50/M input tokens), while Grok 4.1 Fast is better for long-context tasks (2,000,000 tokens).
Direct answer: choose Grok 4.1 Fast for lower token spend and choose Grok 4.1 Fast when your workload needs longer context.
Compare input and output token pricing, context windows, and monthly cost estimates on one page so you can pick the cheaper model fast.
Cost Comparison (1000 input + 500 output tokens, 100 requests/day)
Codex Mini
Grok 4.1 Fast
Cost Differences
Grok 4.1 Fast costs less than Codex Mini
Quick Recommendation
Winner for direct API pricing: Grok 4.1 Fast. At the default workload, Grok 4.1 Fast saves about $12.15/month ($147.825/year) versus Codex Mini.
Feature Comparison
| Feature | Codex Mini | Grok 4.1 Fast |
|---|---|---|
| Provider | OpenAI | xAI |
| Input Price | $1.50/1M tokens | $0.20/1M tokens |
| Output Price | $6.00/1M tokens | $0.50/1M tokens |
| Context Window | 200,000 tokens | 2,000,000 tokens |
| Max Output | 32,768 tokens | 131,072 tokens |
| Category | efficient | efficient |
| Capabilities | textcodereasoning | textreasoningcode |
| Release Date | 2/2/2026 | 1/15/2026 |
Codex Mini vs Grok 4.1 Fast: Which Should You Choose?
Choosing between Codex Mini and Grok 4.1 Fast depends on your priorities: cost efficiency, context length, or raw capability. Grok 4.1 Fast is the more affordable option at $0.20/1M input tokens — 87% cheaper than Codex Mini. Meanwhile, Grok 4.1 Fast offers a significantly larger context window at 2,000,000 tokens vs 200,000 for Codex Mini.
These models come from different providers — OpenAI and xAI — which means different API ecosystems, SDKs, rate limits, and terms of service. If you're already integrated with OpenAI, switching to xAIinvolves migration effort beyond just pricing. Factor in your existing infrastructure when deciding.
Both models are in the efficient category, making this a direct head-to-head comparison. At scale — say 10,000 requests per day — the cost difference adds up: Grok 4.1 Fast would save you roughly $1,215.00/month compared to Codex Mini. For startups and indie developers, that difference can be significant.
Output costs matter too. Codex Mini charges $6.00/1M output tokens vs $0.50 for Grok 4.1 Fast. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. Grok 4.1 Fast has the edge here at $0.50/1M output tokens.
Best Use Cases
Choose Codex Mini when:
- • You're already using OpenAI's API ecosystem
- • You're running high-volume, latency-sensitive workloads
Choose Grok 4.1 Fast when:
- • Budget is a primary concern
- • You need a larger context window (2,000,000 tokens)
- • You need longer outputs (up to 131,072 tokens)
- • You're already using xAI's API ecosystem
- • You're running high-volume, latency-sensitive workloads
Pros and Caveats at a Glance
Codex Mini
- • Input pricing: $1.50/M tokens
- • Output pricing: $6.00/M tokens
- • Context window: 200,000 tokens
- • Max output: 32,768 tokens
Watch out for
- • Higher input cost than Grok 4.1 Fast
- • Higher output cost than Grok 4.1 Fast
- • Smaller context window than Grok 4.1 Fast
Grok 4.1 Fast
- • Input pricing: $0.20/M tokens
- • Output pricing: $0.50/M tokens
- • Context window: 2,000,000 tokens
- • Max output: 131,072 tokens
Watch out for
- • Trade-offs are minor in this matchup.
Try Different Scenarios
Use the calculator below to see how costs change with different usage patterns
Codex Mini (OpenAI)
Grok 4.1 Fast (xAI)
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Sign Up for xAI →Frequently Asked Questions
Which is cheaper, Codex Mini or Grok 4.1 Fast?▼
What is the context window difference between Codex Mini and Grok 4.1 Fast?▼
Which model is better for AI Agent / Agentic Workflows?▼
Which model has better overall pricing for heavy usage?▼
Where can I compare OpenAI and xAI API pricing beyond this model matchup?▼
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