GPT-5.3-Codex vs Grok-3
GPT-5.3-Codex (2026) and Grok-3 (2025) compare a coding-specialized model against a standalone API model. GPT-5.3-Codex ships a 400k-token context window, while Grok-3 ships a 131k-token context window. On pricing, Grok-3 costs $0.80/1M input tokens versus $1.75/1M for the alternative. This page treats the result as workflow and deployment fit, not a universal model winner.
Treat this as a product-type comparison: GPT-5.3-Codex is coding-specialized model, while Grok-3 is standalone API model. Choose based on workflow fit before reading any benchmark or price row as decisive.
Decision scorecard
Local evidence first| Signal | GPT-5.3-Codex | Grok-3 |
|---|---|---|
| Product type | Coding-specialized model | Standalone API model |
| Best for | custom coding agents, code generation, and tool loops | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 400k | 131k |
| Cheapest output | $14/1M tokens | $2.40/1M tokens |
| Provider routes | 3 tracked | 4 tracked |
| Shared benchmarks | 0 shared | 0 shared |
Decision tradeoffs
- GPT-5.3-Codex has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5.3-Codex uniquely exposes Code execution and Computer use in local model data.
- Local decision data tags GPT-5.3-Codex for Coding, RAG, and Agents.
- Grok-3 has the lower cheapest tracked output price at $2.40/1M tokens.
- Grok-3 has broader tracked provider coverage for fallback and route flexibility.
- Grok-3 uniquely exposes Multimodal in local model data.
- Local decision data tags Grok-3 for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
GPT-5.3-Codex
$4,900
Cheapest tracked route/tier: OpenRouter
Grok-3
$1,240
Cheapest tracked route/tier: Chutes AI
Estimated monthly gap: $3,660. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- Grok-3 is $11.60/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Code execution and Computer use before moving production traffic.
- Grok-3 adds Multimodal in local capability data.
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- GPT-5.3-Codex is $11.60/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Multimodal before moving production traffic.
- GPT-5.3-Codex adds Code execution and Computer use in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-02-05 | 2025-02-17 |
| Context window | 400k | 131k |
| Parameters | — | — |
| Architecture | Decoder Only | - |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Weights | Not released | Not released |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | 2025-08 | 2025-04 |
Pricing and availability
| Pricing attribute | GPT-5.3-Codex | Grok-3 |
|---|---|---|
| Input price | $1.75/1M tokens | $0.80/1M tokens |
| Output price | $14/1M tokens | $2.40/1M tokens |
| Providers |
Capabilities
| Capability | GPT-5.3-Codex | Grok-3 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | No | Yes |
| Reasoning | Yes | Yes |
| JSON / Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | No |
| IDE integration | No | No |
| Computer use | Yes | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark scores are currently available for this pair.
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Last reviewed: 2026-07-10. Data sourced from public model cards and provider documentation.