> ## Documentation Index > Fetch the complete documentation index at: https://docs.nativeline.ai/llms.txt > Use this file to discover all available pages before exploring further. # External APIs Overview > Integrate third-party services into your app # External APIs External APIs let you add specialized functionality to your app — AI capabilities, payment processing, weather data, and more. ## What Are External APIs? APIs (Application Programming Interfaces) let your app communicate with external services: ``` Your App → HTTP Request → External Service ↓ Your App ← Response Data ← External Service ``` *** ## Available Integrations Add AI chat, text generation, and completion features Accept payments and manage subscriptions Apple Maps, directions, and geocoding WeatherKit and OpenWeather data Generic guide for any API *** ## How API Integration Works ### 1. Get API Credentials Most APIs require authentication: * **API Key** — A secret string identifying your app * **OAuth** — User-authorized access (for user data) ### 2. Configure in App Tell Nativeline about the API: ``` Add OpenAI integration with API key: sk-xxxxx ``` ### 3. Make Requests The AI handles the technical details. You describe what you want: ``` When user taps "Generate", send their text to OpenAI and display the response. ``` *** ## API Security Never expose API keys in your code or share them publicly. Keys give access to your account and can incur charges. ### Nativeline Security Nativeline stores API keys securely: * Encrypted in macOS Keychain * Not committed to source code * Not visible in compiled app (properly) ### Best Practices * Use environment variables when possible * Rotate keys if exposed * Set spending limits in API dashboards * Consider server-side proxies for production *** ## Common API Patterns ### Request-Response Most APIs follow this pattern: ```swift theme={null} // 1. Build request with data let request = OpenAIRequest(prompt: userInput) // 2. Send to API let response = try await openAI.complete(request) // 3. Use the response displayResult(response.text) ``` ### Handling Errors APIs can fail — handle errors gracefully: ``` Handle API errors: - Network errors: Show "Check your connection" - Rate limits: Show "Please wait and try again" - Invalid key: Show "Configuration error" ``` ### Loading States Show progress while waiting for responses: ``` While waiting for the API response: - Show loading indicator - Disable the send button - Show progress text like "Thinking..." ``` *** ## Free vs Paid APIs ### Typically Free * Apple Maps (built-in) * WeatherKit (with Apple Developer account) * Many APIs have free tiers ### Typically Paid (with free tiers) | API | Free Tier | | ----------- | ------------------------------- | | OpenAI | \$5 credit for new accounts | | Stripe | Free until you process payments | | Google Maps | \$200/month credit | | OpenWeather | 1,000 calls/day | ### Cost Considerations * Monitor usage in API dashboards * Set spending limits * Cache responses to reduce calls * Use rate limiting in your app *** ## Choosing the Right API ### For AI Features → [OpenAI](/integrations/external-apis/openai) Best for: Chat bots, text generation, content creation, summarization ### For Payments → [Stripe](/integrations/external-apis/stripe) Best for: One-time payments, subscriptions, marketplace payouts ### For Maps & Location → [Apple Maps](/integrations/external-apis/maps) Best for: Maps display, directions, place search, geocoding ### For Weather → [WeatherKit or OpenWeather](/integrations/external-apis/weather) Best for: Current conditions, forecasts, historical data ### For Anything Else → [Generic API Guide](/integrations/external-apis/other) Works with any REST API *** ## Getting Started Pick the service that provides what you need Sign up at the provider's website Usually found in settings or developer dashboard Add the key and tell the AI to use it Describe what you want to accomplish *** ## Next Steps Add AI capabilities Accept payments