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Get started freeGPT-5.1 Codex vs GPT-4 Turbo
Compare GPT-5.1 Codex and GPT-4 Turbo. Build AI products powered by either model on Appaca.
Model Comparison
| Feature | GPT-5.1 Codex | GPT-4 Turbo |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Model Type | text | text |
| Context Window | 400,000 tokens | 128,000 tokens |
| Input Cost | $1.25/ 1M tokens | $10.00/ 1M tokens |
| Output Cost | $10.00/ 1M tokens | $30.00/ 1M tokens |
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Build your first app freeStrengths & Best Use Cases
GPT-5.1 Codex
OpenAI1. Purpose-Built for Agentic Coding
- Designed specifically for environments where the model acts as an autonomous or semi-autonomous coding agent.
- Optimized for multi-step reasoning in code tasks such as planning, refactoring, debugging, file generation, and tool coordination.
2. Enhanced Coding Intelligence
- Extends GPT-5.1's advanced reasoning capabilities to handle complex software architecture decisions.
- Better accuracy in code generation across languages (JavaScript, Python, TypeScript, Go, Rust, etc.).
- Produces cleaner, more idiomatic code aligned with modern frameworks and best practices.
3. Superior Tool Use & Code Navigation
- Excels at reading, understanding, and transforming multi-file codebases.
- Works well with Codex workflows that simulate real developer tooling.
- Strong at following function signatures, constraints, and code patterns within an existing project.
4. Long-Range Context Awareness
- 400,000-token context window enables the model to ingest large repositories or multiple files simultaneously.
- Supports deep analysis of project structures, dependencies, and cross-file logic.
5. Multi-Modal Development Capabilities
- Accepts text + image input and output - suitable for tasks like:
- Reading UI mockups or screenshots to generate code
- Understanding architectural diagrams
- Reviewing images of whiteboard sessions
6. Agentic Workflow Optimization
- Built to manage longer chains of thought and execution typically required in:
- Automated code repair
- Project bootstrapping
- Linting and migration tasks
- Long-running coding agents using planning + execution loops
7. Continually Updated Model Snapshot
- Codex-specific version receives regular upgrades behind the scenes.
- Ensures the latest coding improvements without requiring developers to update model names.
8. Reliable Instruction Following
- Highly consistent in honoring explicit constraints:
- Code styles
- Folder structures
- API contracts
- Framework conventions
9. Broad API Support
- Works across Chat Completions, Responses API, Realtime, Assistants, and more.
- Ideal for apps that need live, reasoning-heavy coding agents or generative dev environments.
GPT-4 Turbo
OpenAI1. Strong reasoning for its generation
- Next-gen version of GPT-4 designed to be cheaper and faster than the original.
- Good for analytical tasks, structured writing, coding guidance, and multi-step reasoning.
2. Image input support
- Accepts images and provides text-only outputs.
- Useful for OCR, visual Q&A, document extraction, UI analysis, and design interpretation.
3. Stable performance
- Predictable model behavior suitable for legacy systems still built on GPT-4.
- Works reliably for established pipelines and enterprise workloads.
4. Large 128K context window
- Handles long documents, multi-file inputs, or extended conversational sessions.
- Allows complex prompt chaining and large instruction sets.
5. Broad endpoint compatibility
- Works with Chat Completions, Responses API, Realtime API, Assistants, Batch, Fine-tuning, Embeddings, and more.
- Supports streaming and function calling.
6. Good choice for cost-controlled GPT-4-class workloads
- Although older, still useful for teams who want GPT-4-level reasoning without upgrading immediately.
- A midpoint between legacy GPT-4 and modern GPT-4o/5.1 models.
7. Text-only output simplifies downstream use
- Ensures deterministic outputs for applications that need reliable text generation.
- Good for RAG, data pipelines, automation tools, and enterprise systems.
8. Recommended migration path
- OpenAI now recommends using GPT-4o or GPT-5.1 for improved speed, cost, reasoning, and multimodal capability.
- GPT-4 Turbo remains available for backward compatibility and stability.
Prompts to Get Started
Use these prompts to power AI products you build on Appaca. Each works great with the models above.
Best for GPT-5.1 Codex
textDecision-Making Framework
Structure a difficult decision using a clear framework and analysis.
Urgent vs Important Sort
Sort a mixed task list into the Eisenhower Matrix quadrants with clear actions.
Technical Debt Analysis
Analyse and prioritise technical debt in a codebase or system.
Best for GPT-4 Turbo
textDating App Opening Message
Write a genuine, creative opening message for a dating app match. Stands out by referencing their profile specifically.
Indemnification Clause Explainer
Explain indemnification clauses in contracts in plain language.
LinkedIn About Summary
Write a compelling LinkedIn About section that attracts recruiters and networking opportunities. First-person, story-driven.