Skip to main content
Many products need a local copy of customer data from CRMs, file stores, ticketing tools, billing systems, calendars, or communication apps. Doing this reliably means handling OAuth, polling, pagination, rate limits, retries, deletions, and missed webhooks for every provider. Nango gives you a function runtime for this pattern. A sync function fetches data from the external API, writes records into Nango’s cache, and notifies your app when records change. Your app then reads the changed records by cursor.

​
When this fits

Use Nango to sync external API data when you need to:
  • Keep a local database or search index updated from customer tools.
  • Feed RAG pipelines with fresh external data.
  • Detect changes from APIs that do not offer reliable webhooks.
  • Combine polling with provider webhooks for near real-time updates.
  • Sync large datasets without restarting from scratch after failures.
For one-off reads or writes, use Run external API operations.

​
How Nango fits in

  1. Your user authorizes an integration with Nango.
  2. You enable a template sync function or deploy your own.
  3. Nango runs the sync function on its schedule, or when a provider webhook arrives.
  4. The function saves records into Nango’s records cache.
  5. Nango sends your app a webhook when records change.
  6. Your app reads changed records with a cursor and stores them in your system.
The same foundation works for classic data sync, indexing, RAG ingestion, and trigger-style workflows.
You can also pair sync functions with Action functions for two-way sync: sync reads from the external API, then call a function on demand to write changes back.