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Get started freeGPT-5 Codex vs Grok 3
Compare GPT-5 Codex and Grok 3. Build AI products powered by either model on Appaca.
Model Comparison
| Feature | GPT-5 Codex | Grok 3 |
|---|---|---|
| Provider | OpenAI | xAI |
| Model Type | text | text |
| Context Window | 400,000 tokens | 131,072 tokens |
| Input Cost | $1.25/ 1M tokens | $3.00/ 1M tokens |
| Output Cost | $10.00/ 1M tokens | $15.00/ 1M tokens |
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Build your first app freeStrengths & Best Use Cases
GPT-5 Codex
OpenAI1. Purpose-Built for Agentic Coding
- Optimized specifically for scenarios where the model must act as an autonomous or semi-autonomous coding agent.
- Tailored for Codex workflows such as planning, editing, debugging, and multi-step tool-driven code tasks.
2. Advanced Coding Reasoning
- Extends GPT-5's higher reasoning mode to better handle complex software logic and multi-file dependencies.
- Produces more accurate, structured, and maintainable code across modern programming languages.
3. Strong Tool Use in Developer-Like Environments
- Designed for Codex's agent environment, enabling the model to:
- Read and modify files
- Follow function signatures and API contracts
- Navigate codebases with awareness of context and structure
4. Large Context Window for Full-Project Understanding
- 400,000-token context allows ingestion of:
- Entire repositories
- Multiple files at once
- Architectural descriptions
- Enables long-range reasoning across codebases rather than isolated snippets.
5. Multimodal Capability for Development Tasks
- Accepts text and image as input (great for screenshots of error logs, UI mocks, whiteboards).
- Outputs text only, focusing its output precision on code, reasoning, and documentation.
6. Continuous Snapshot Updates
- The underlying model version is regularly upgraded behind the scenes.
- Ensures developers always use the best coding-enhanced GPT-5 variant without changing model names.
7. Reliable Instruction Following
- Very strong adherence to constraints like:
- File/folder structure requirements
- Framework conventions
- Naming patterns
- Linting rules
- Makes it suitable for production coding agents.
8. Broad API Integration
- Available only in the Responses API, giving you:
- Streaming
- Structured outputs
- Function calling
- Allows creation of interactive coding tools and agent workflows with tight model control.
Grok 3
xAI1. Strong enterprise-grade reasoning
- Built for deep logical reasoning, structured decision-making, and multi-step analysis.
- Performs exceptionally in domains requiring precision: law, finance, healthcare, and STEM.
2. Excellent at data extraction and summarization
- Optimized for structured extraction from documents, PDFs, tables, and complex text.
- Ideal for enterprise workflows like reporting, compliance automation, or knowledge mining.
3. High-performance coding capabilities
- Excels at code generation, debugging, refactoring, and explaining code.
- Competitive with top-tier coding models for multi-file, long-context code reasoning.
4. Supports function calling and structured outputs
- Integrates cleanly with agent frameworks and external tools.
- Predictable, schema-aligned responses suitable for production systems.
5. Large 131K context window
- Handles long documents, transcripts, contracts, codebases, or multi-document tasks.
- Useful for ingesting highly technical materials in one pass.
6. Efficient cost structure with cached token pricing
- Cached inputs: only $0.75 / 1M tokens, enabling large-scale systems.
- Encourages reuse for powerful retrieval-augmented workflows.
7. Enterprise reliability and availability
- Supported across multiple regions (us-east-1, eu-west-1).
- Consistent rate limits: 600 requests/min.
- Suitable for production-grade apps with stability requirements.
8. Supports advanced search capabilities
- Optional Live Search add-on for real-time knowledge retrieval.
- Pricing: $25 per 1K sources.
Prompts to Get Started
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Best for GPT-5 Codex
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Best for Grok 3
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Ask a recent buyer or seller client for a testimonial. Friendly, specific, and low-effort for the client to respond.