API Integration Guide
Prerequisite Knowledge: LLM Fundamentals
Overview
Integrating AI into your application starts with choosing the right Model Provider. While there are dozens of options, 95% of production applications today build on top of three core providers: OpenAI, Anthropic, and Google.
This section guides you through connecting these powerful models to your frontend applications.
Provider Comparison Matrix
| Feature | OpenAI (GPT-4o) | Anthropic (Claude 3.5 Sonnet) | Google (Gemini 1.5 Pro) |
|---|---|---|---|
| Best For | General Purpose, Function Calling, Structured Data | Coding, Reasoning, Creative Writing | Long Context (2M tokens), Multimodal (Video) |
| Speed | ⚡️⚡️⚡️⚡️ (Fast) | ⚡️⚡️⚡️ (Moderate) | ⚡️⚡️⚡️ (Moderate) |
| Cost | 💰💰 (Moderate) | 💰💰 (Moderate) | 💰 (Low) |
| Context Window | 128k Tokens | 200k Tokens | 2M Tokens |
| Tool Use | Excellent | Excellent | Good |
| Ecosystem | Massive (Assistants API, Realtime API) | Strong (Artifacts, Computer Use) | Growing (Deep Google Integration) |
Decision Tree: Which API Should I Use?
Cost Comparison (Estimates)
Prices are per 1 Million Tokens (approx. 750,000 words). Prices subject to change. Last updated: Jan 2026.
| Model | Input Cost | Output Cost | Total for ~1000 requests |
|---|---|---|---|
| GPT-4o | $2.50 | $10.00 | ~$5.00 |
| Claude 3.5 Sonnet | $3.00 | $15.00 | ~$6.00 |
| Gemini 1.5 Pro | $1.25 | $5.00 | ~$2.50 |
| GPT-4o-mini | $0.15 | $0.60 | ~$0.30 |
Takeaway: For simple tasks (summarization, simple chat), use GPT-4o-mini. It is 20x cheaper than the flagship models.
Detailed Integration Guides
Ready to write code? Follow these specific guides:
- OpenAI Guide: The industry standard. Covers setup, streaming, and tool calling.
- Anthropic Guide: Best for "smart" tasks. Covers the Anthropic SDK.
- HuggingFace Guide: For open-source models and free inference APIs.
Rate Limits & Quotas
When moving to production, you will hit limits.
Common Limits:
- RPM (Requests Per Minute): How many API calls you can make.
- TPM (Tokens Per Minute): How much text you can send/receive.
Handling Limits:
- Exponential Backoff: If you get a
429 Too Many Requests, wait 1s, then 2s, then 4s... - Tier Upgrades: Most providers increase limits as you spend more (e.g., OpenAI Usage Tiers).
- Load Balancing: Advanced users rotate keys or providers.
Next Steps
- Get an API Key from your chosen provider.
- Install the SDK (
npm install openaiornpm install @anthropic-ai/sdk). - Make your first call following our OpenAI Guide.