Overview
Functions are Nango’s TypeScript runtime for building custom integrations. You write integration logic in TypeScript and deploy it to Nango. Functions execute with built-in access to authenticated APIs, retries, storage, and observability. Functions are a flexible primitive that you can use to build any integration use-case, from simple API actions to complex data syncs, RAG pipelines & real-time webhook ingestion. Pair Functions with the AI integration builder to generate and maintain integration code faster—combining the speed of AI with human-reviewable code you fully control.How it works
1. Define a function- Typescript
- Other languages (cURL)

Capabilities
Runtime and execution
- Runs inside Nango
- Isolated execution per customer and per run
- Elastic scaling & fast startup time (less than 100ms)
- Flexible use-cases: long-running syncs, rapid-fire actions, etc.
- Triggered by API calls, schedules, webhooks, or life-cycle events
Developer experience
- TypeScript-first, but compatible with any code base (HTTP-controlled)
- Generate & maintain integration code with your favorite AI models
- Local development, local dry runs & testing framework
- CLI-based workflow & CI/CD integration
- Code lives in your own Git repository
Runtime SDK
- Authenticated API requests
- Retries & rate-limit handling
- Sync engine with caching & checkpointing for ETL & RAG
- Data transformation utilities
- Runtime and compile-time data validation & auto-completion
State and configuration
- Per-customer configuration & logical branching
- Per-customer key-value storage
- Compose functions into workflows
Observability
- Execution & custom logs
- Metrics and monitoring
- Debuggable failures
- OpenTelemetry export
Use cases
Functions are a powerful & flexible primitive to support any complex integration use-case:- Tool calling & MCP servers
- Data syncing & incremental updates
- RAG pipelines and large dataset ingestion
- Triggers and change detection
- Webhook ingestion and processing
- Per-customer integration logic
- API unification