GPT-5.3 Codex vs Grok 4
Compare pricing, context windows, and strengths for GPT-5.3 Codex by OpenAI and Grok 4 by xAI - and see how to put either to work in Appaca.
GPT-5.3 Codex
Most capable agentic coding model to date, optimized for long-horizon software engineering tasks with configurable reasoning and multimodal input.
View GPT-5.3 CodexGrok 4
A flagship multimodal model excelling in natural language, math, and deep reasoning with unmatched all-around performance.
View Grok 4GPT-5.3 Codex vs Grok 4 at a glance
Specs and pricing side by side, from the Appaca AI models directory.
| Spec | GPT-5.3 Codex | Grok 4 |
|---|---|---|
| Provider | OpenAI | xAI |
| Model type | Text | Text |
| Context window | 400K tokens | 256K tokens |
| Input price | $1.75 / 1M tokens | $3 / 1M tokens |
| Output price | $14 / 1M tokens | $15 / 1M tokens |
| Status | Current | Current |
How GPT-5.3 Codex and Grok 4 differ
What the numbers mean in practice when choosing between GPT-5.3 Codex and Grok 4.
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GPT-5.3 Codex is 42% cheaper on input tokens ($1.75 vs $3 per million), which adds up quickly in document-heavy workloads.
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GPT-5.3 Codex is 7% cheaper on output tokens ($14 vs $15 per million) - the bigger factor for tools that generate long documents.
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GPT-5.3 Codex's 400K tokens context window is roughly 1.6x larger than Grok 4's 256K tokens, so it can work across bigger codebases, contracts, or archives in one pass.
Strengths side by side
Where each model shines, according to benchmarks and provider positioning.
GPT-5.3 Codex
1. Strongest Codex Model for Agentic Engineering
- OpenAI positions GPT-5.3 Codex as its most capable agentic coding model to date.
- Built for long-horizon software engineering tasks that require planning, iteration, and reliable code transformation across files.
2. Configurable Reasoning + Multimodal Input
- Supports configurable reasoning effort from low to xhigh so teams can trade off depth against latency.
- Accepts both text and image inputs while producing text output.
3. Large Context for Real Codebases
- 400 k token context window helps it work across larger repositories, implementation plans, and supporting documentation.
- Allows up to 128 k output tokens for longer code generations, patches, and technical write-ups.
4. Current Knowledge for Modern Dev Workflows
- Knowledge cut-off of Aug 31 2025 keeps it aligned with newer frameworks, libraries, and tooling.
- Supports streaming, function calling, and structured outputs for agent-style coding workflows.
Grok 4
1. Flagship-level reasoning and math performance
- Designed for world-class reasoning depth, precision, and multi-step logical chains.
- Excels at STEM, mathematics, symbolic operations, proofs, and analytical workloads.
2. Powerful multimodal understanding
- Supports text, images, and other modalities.
- Handles cross-modal reasoning tasks requiring context synthesis.
3. Extreme capability across diverse tasks
- Positioned as a top-tier 'jack of all trades' model.
- Strong in natural language, coding, knowledge retrieval, and structured generation.
4. Large 256K context window
- Enables analysis of long documents, entire codebases, multi-document packs, and extensive agent sessions.
- Supports workloads that require persistent reasoning across large inputs.
5. Advanced developer tooling support
- Function calling for tool-augmented workflows.
- Structured outputs for predictable, schema-controlled generation.
- Integrates smoothly with agents and complex automation pipelines.
6. Efficient caching for cost reduction
- Cached input tokens discounted to $0.75 / 1M tokens.
- Encourages RAG, retrieval pipelines, and multi-step conversational workflows.
7. Production-ready performance
- Stable rate limits: 480 requests per minute.
- High token throughput: 2,000,000 tokens per minute.
- Available across multiple xAI regional clusters.
8. Optional Live Search augmentation
- Add-on: $25 per 1K sources.
- Enhances factual accuracy and real-time information retrieval.
Use GPT-5.3 Codex or Grok 4 - or both
Appaca is the AI workspace for operators. Build internal tools and AI co-workers powered by GPT-5.3 Codex or Grok 4 - connected to your real data and ready for your whole team. No code, no deployment.
Describe it, and it's built
Tell the Appaca agent the internal tool you need and it builds a working app powered by GPT-5.3 Codex or Grok 4. No code, no API keys, no deployment.
Switch models without rebuilding
Start on GPT-5.3 Codex, test the same tool on Grok 4, and keep whichever performs better - the rest of your app stays exactly as it is.
Automated for the whole team
Schedule tools to run on autopilot - daily digests, weekly reports, real-time triggers - and share them with your whole team from one workspace.
Describe it, and it's built
Tell the Appaca agent what your team needs and it builds a working app powered by GPT-5.3 Codex or Grok 4 - connected to the tools you already use.
Related comparisons
See how GPT-5.3 Codex and Grok 4 stack up against other models in the directory.
FAQs
GPT-5.3 Codex is generally cheaper: $1.75 input / $14 output per million tokens, versus $3 / $15 for Grok 4. Actual cost depends on how many tokens your workload reads and writes.
GPT-5.3 Codex has the larger context window at 400K tokens, compared to 256K tokens for Grok 4. A larger window means the model can consider more text at once - useful for long contracts, codebases, or months of records.
It depends on the job. Compare the pricing, context window, and strengths above against your workload - and remember the choice isn't permanent. In Appaca you can build a tool on GPT-5.3 Codex, test the same tool on Grok 4, and switch at any time without rebuilding anything.
Yes. Appaca is a no-code AI workspace: describe the internal tool your team needs and the Appaca agent builds it as a working app powered by GPT-5.3 Codex, Grok 4, or any other model in the directory - with a built-in database, team access, and integrations. No API keys to wire up and nothing to deploy.
Build AI tools with GPT-5.3 Codex or Grok 4
Describe the tool your team needs and get a working app powered by the model you choose - with a built-in database, team access, and integrations. No code, no deployment.