GPT-5.3 Codex vs Grok Code Fast 1
GPT-5.3 Codex vs Grok Code Fast 1: Grok Code Fast 1 is cheaper for input-heavy usage ($0.20/M vs $1.75/M input tokens), while GPT-5.3 Codex is better for long-context tasks (256,000 tokens).
Direct answer: choose Grok Code Fast 1 for lower token spend and choose GPT-5.3 Codex 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)
GPT-5.3 Codex
Grok Code Fast 1
Cost Differences
Grok Code Fast 1 costs less than GPT-5.3 Codex
Quick Recommendation
Winner for direct API pricing: Grok Code Fast 1. At the default workload, Grok Code Fast 1 saves about $23.40/month ($284.70/year) versus GPT-5.3 Codex.
Feature Comparison
| Feature | GPT-5.3 Codex | Grok Code Fast 1 |
|---|---|---|
| Provider | OpenAI | xAI |
| Input Price | $1.75/1M tokens | $0.20/1M tokens |
| Output Price | $14.00/1M tokens | $1.50/1M tokens |
| Context Window | 256,000 tokens | 256,000 tokens |
| Max Output | 32,768 tokens | 32,768 tokens |
| Category | coding | standard |
| Capabilities | textcode | textcodereasoning |
| Release Date | 3/1/2026 | 2/1/2026 |
GPT-5.3 Codex vs Grok Code Fast 1: Which Should You Choose?
Choosing between GPT-5.3 Codex and Grok Code Fast 1 depends on your priorities: cost efficiency, context length, or raw capability. Grok Code Fast 1 is the more affordable option at $0.20/1M input tokens — 89% cheaper than GPT-5.3 Codex.
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.
These models target different tiers: GPT-5.3 Codex is a coding model while Grok Code Fast 1 is standard. This means they're optimized for different workloads. Grok Code Fast 1 targets more demanding workloads, while GPT-5.3 Codex provides a cost-effective option for everyday tasks.
Output costs matter too. GPT-5.3 Codex charges $14.00/1M output tokens vs $1.50 for Grok Code Fast 1. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. Grok Code Fast 1 has the edge here at $1.50/1M output tokens.
Best Use Cases
Choose GPT-5.3 Codex when:
- • You're already using OpenAI's API ecosystem
Choose Grok Code Fast 1 when:
- • Budget is a primary concern
- • You need more capabilities (reasoning)
- • You're already using xAI's API ecosystem
Pros and Caveats at a Glance
GPT-5.3 Codex
- • Input pricing: $1.75/M tokens
- • Output pricing: $14.00/M tokens
- • Context window: 256,000 tokens
- • Max output: 32,768 tokens
Watch out for
- • Higher input cost than Grok Code Fast 1
- • Higher output cost than Grok Code Fast 1
Grok Code Fast 1
- • Input pricing: $0.20/M tokens
- • Output pricing: $1.50/M tokens
- • Context window: 256,000 tokens
- • Max output: 32,768 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
GPT-5.3 Codex (OpenAI)
Grok Code Fast 1 (xAI)
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Sign Up for xAI →Frequently Asked Questions
Which is cheaper, GPT-5.3 Codex or Grok Code Fast 1?▼
What is the context window difference between GPT-5.3 Codex and Grok Code Fast 1?▼
Which model is better for AI Chatbot?▼
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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