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Get started freeGPT-5.1 vs GPT-4 Turbo
Compare GPT-5.1 and GPT-4 Turbo. Build AI products powered by either model on Appaca.
Model Comparison
| Feature | GPT-5.1 | 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 |
Stop choosing. Use both.
With Appaca you don't have to pick — build apps that are powered by GPT-5.1, GPT-4 Turbo, for your specific use case.
Build your first app freeStrengths & Best Use Cases
GPT-5.1
OpenAI1. Configurable Reasoning for Agentic Tasks
- Built to excel in autonomous or semi-autonomous coding workflows, with adjustable reasoning effort for planning, refactoring and debugging.
2. Fast Multi-Modal Input with Large Output
- Accepts both text and image inputs while producing text outputs.
- Offers up to 128 k output tokens, allowing long responses and code generation across multiple files.
3. Large Context & Knowledge Cut-Off
- 400 k token context window supports processing large codebases or documents.
- Knowledge cut-off of Sep 30 2024 ensures familiarity with recent tools and frameworks.
4. Reasoning Token Support
- Provides explicit support for reasoning tokens, enabling developers to fine-tune the balance between reasoning depth and speed.
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
textTwitter/X Thread Explainer
Break down a complex topic into an engaging Twitter/X thread.
Referral Program Announcement Copy
Write copy to launch or promote a customer referral program.
Technical Interview Questions
Generate structured technical interview questions for a specific engineering role.
Best for GPT-4 Turbo
textBook Dedication
Write a meaningful book dedication for a published or self-published work. Honors the right people in the right words.
Airport Navigation Guide
Write a navigation guide for a major international airport for travelers transiting or departing. Practical and time-saving.
Just Sold Announcement
Write a just sold announcement for social media or direct mail. Builds agent credibility and generates prospecting interest.