Best AI APIs for Developers: Build Smarter Apps

If you're building AI-powered features into your product, choosing the right API matters. I've integrated all the major ones - here's what works best for what.

The APIs Ranked

Anthropic Claude API

Best for: Complex reasoning, code generation, structured outputs

Claude is my default API for any task requiring nuanced understanding. The API gives you access to the same models powering Claude Code.

• Models: Claude Opus 4, Sonnet 4.5, Haiku 4.5
• Strengths: Instruction following, long context (200K), tool use, code quality
• Pricing: $3-15 per million input tokens depending on model
• Best for: Development tools, content generation, data analysis

OpenAI API

Best for: General-purpose AI features, broad ecosystem

The most widely used AI API. Massive ecosystem of libraries, tutorials, and community support.

• Models: GPT-4o, GPT-4o Mini, o1
• Strengths: Broad capabilities, fast inference, image generation (DALL-E)
• Pricing: $2.50-15 per million input tokens
• Best for: Chatbots, image generation, embeddings

Google Gemini API

Best for: Multimodal applications, long documents

Google's offering with the largest context window and strong multimodal capabilities.

• Models: Gemini 2.5 Pro, Flash
• Strengths: 1M+ token context, video understanding, fast
• Pricing: Competitive, generous free tier
• Best for: Document analysis, multimodal apps, cost-sensitive applications

Open Source (via API providers)

Best for: Cost optimization, data privacy, customization

Run open-source models like Llama, Mistral, and DeepSeek through providers like Together, Fireworks, or self-hosted.

• Models: Llama 3.3, DeepSeek V3, Mistral Large
• Strengths: No vendor lock-in, customizable, often cheaper
• Pricing: $0.20-3 per million tokens via hosted providers
• Best for: High-volume, cost-sensitive applications

Choosing Your API

| Need | Recommended API | |------|----------------| | Code generation | Anthropic Claude | | General chatbot | OpenAI GPT-4o | | Long documents | Google Gemini | | Budget-conscious | Open source via Together/Fireworks | | Image generation | OpenAI (DALL-E) or Google | | Embeddings | OpenAI or Voyage AI |

Integration Tips

Start with one API. Don't over-engineer a multi-provider setup on day one. Pick the best fit for your primary use case and ship.

Use streaming. Every major API supports streaming responses. Users hate waiting for a complete response. Stream tokens as they generate.

Cache aggressively. Same prompts = same outputs (at temperature 0). Cache responses for identical inputs to cut costs by 50-80%.

Handle rate limits gracefully. All APIs have rate limits. Build retry logic with exponential backoff from the start.

My API Stack

For building AI-powered products as a solo operator:

1. Anthropic Claude - Primary API for complex tasks, code generation, content
2. OpenAI - Embeddings and image generation
3. Open source - High-volume, low-complexity tasks to manage costs

Total API spend: $100-300/month across all products. Much cheaper than hiring a team.

For the full tool stack, see AI Tools for Solo Operators.

Frequently Asked Questions

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