GPT-5.3-Codex vs Grok Build 0.1
GPT-5.3-Codex (2026) and Grok Build 0.1 (2026) are agentic coding models from OpenAI and xAI. GPT-5.3-Codex ships a 400k-token context window, while Grok Build 0.1 ships a 256k-token context window. On pricing, GPT-5.3-Codex costs $1.75/1M input tokens; Grok Build 0.1 ranges from $1 to $2/1M input tokens by tier. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Grok Build 0.1 is safer overall; choose GPT-5.3-Codex when coding workflow support matters.
Decision scorecard
Local evidence first| Signal | GPT-5.3-Codex | Grok Build 0.1 |
|---|---|---|
| Best for | custom coding agents, code generation, and tool loops | custom coding agents, code generation, and tool loops |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 400k | 256k |
| Cheapest output | $14/1M tokens | $2/1M tokens |
| Provider routes | 3 tracked | 3 tracked |
| Shared benchmarks | 0 rows | 0 rows |
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 Vision and Code execution in local model data.
- Local decision data tags GPT-5.3-Codex for Coding, RAG, and Agents.
- Grok Build 0.1 has the lower cheapest tracked output price at $2/1M tokens.
- Local decision data tags Grok Build 0.1 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 Build 0.1
$1,300
Cheapest tracked route/tier: xAI Console
Estimated monthly gap: $3,600. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Vercel AI Gateway and OpenRouter; start route-level A/B tests there.
- Grok Build 0.1 is $12/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision and Code execution before moving production traffic.
- Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
- GPT-5.3-Codex is $12/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- GPT-5.3-Codex adds Vision and Code execution in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-02-05 | 2026-05-14 |
| Context window | 400k | 256k |
| Parameters | — | — |
| Architecture | decoder only | - |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2025-08 | - |
Pricing and availability
| Pricing attribute | GPT-5.3-Codex | Grok Build 0.1 |
|---|---|---|
| Input price | $1.75/1M tokens |
|
| Output price | $14/1M tokens |
|
| Providers |
Capabilities
| Capability | GPT-5.3-Codex | Grok Build 0.1 |
|---|---|---|
| Vision | Yes | No |
| Multimodal | No | No |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on vision: GPT-5.3-Codex and code execution: GPT-5.3-Codex. Both models share reasoning mode, function calling, tool use, and structured outputs, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, GPT-5.3-Codex lists $1.75/1M input and $14/1M output tokens on the cheapest tracked provider, while Grok Build 0.1 lists tiered pricing: 0-200,001t is $1/1M input and $2/1M output; 200,001t+ is $2/1M input and $4/1M output. A 70/30 input-output blend puts Grok Build 0.1 lower by about $4.13 per million blended tokens. For tiered rows, this cheapest-track view can understate interactive or fast-lane spend, so compare the tier you will actually use. Availability is 3 providers versus 3, so concentration risk also matters.
Choose GPT-5.3-Codex when coding workflow support and larger context windows are central to the workload. Choose Grok Build 0.1 when coding workflow support and lower cheapest-tier input-token cost are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, GPT-5.3-Codex or Grok Build 0.1?
GPT-5.3-Codex supports 400k tokens, while Grok Build 0.1 supports 256k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, GPT-5.3-Codex or Grok Build 0.1?
GPT-5.3-Codex lists $1.75/1M input and $14/1M output tokens on the cheapest tracked provider. Grok Build 0.1 lists tiered pricing: 0-200,001t is $1/1M input and $2/1M output; 200,001t+ is $2/1M input and $4/1M output. Compare the tier you will actually use; cheap async pricing can overstate savings for interactive workflows. Provider discounts or batch pricing can still change the final bill.
Is GPT-5.3-Codex or Grok Build 0.1 open source?
GPT-5.3-Codex is listed under Proprietary. Grok Build 0.1 is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, GPT-5.3-Codex or Grok Build 0.1?
GPT-5.3-Codex has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for reasoning mode, GPT-5.3-Codex or Grok Build 0.1?
Both GPT-5.3-Codex and Grok Build 0.1 expose reasoning mode. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Where can I run GPT-5.3-Codex and Grok Build 0.1?
GPT-5.3-Codex is available on OpenRouter, OpenAI API, and Vercel AI Gateway. Grok Build 0.1 is available on xAI Console, Vercel AI Gateway, and OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-25. Data sourced from public model cards and provider documentation.