Written by Josh Hutter
Originally published August 2022 • Updated March 2026

When working with APIs, one of the most important decisions you’ll make is how to retrieve and sync data efficiently.

Two common approaches are full API calls and incremental API calls. Understanding the difference between them—and when to use each—can significantly improve performance, reduce load times, and keep your data accurate.

A full API call retrieves all available data, while an incremental API call only returns data that has changed since the last request. Incremental calls are faster and more efficient, while full calls ensure complete data accuracy.

What is a Full API Call?

A full API call returns the complete dataset available from an endpoint.

This means every record is retrieved each time the request is made—regardless of whether the data has changed.

When full API calls are useful:

  • Initial data setup or first-time sync
  • Data validation or auditing
  • Recovering from missed updates or system errors

Because full calls return everything, then tend to be:

  • Slower
  • More resource-intensive
  • Less efficient for frequent use

However, they are critical for ensuring your system has 100% complete and accurate data.

What Is an Incremental API Call?

An incremental API call returns only the data that has changed since your last request.

Instead of pulling the entire dataset, it focuses on updates—such as:

  • New records
  • Modified records
  • Deleted records

This makes incremental calls significantly more efficient.

Benefits of incremental API calls:

  • Faster response times
  • Reduced server load
  • Lower bandwidth usage
  • Ideal for frequent syncing

Incremental calls rely on parameters like timestamps or update markers to determine what has changed.

Feature Full API Call Incremental API Call
Data returned All records Only updated records
Performance Slower Faster
Resource usage High Low
Best use case Initial sync, audits Ongoing updates
Frequency Every 2 hours Every 30 minutes

Best Practices for API Data Sync

To balance performance and accuracy, we recommend combining full and incremental calls strategically.

FMTC recommends:

  • Run full API calls every 2 hours
  • Run incremental API calls every 30 minutes

This ensures:

  • Your system stays up to date with minimal delay
  • You maintain a reliable fallback for data consistency
  • You avoid unnecessary strain on your infrastructure

This hybrid model provides the best of both worlds: efficiency + reliability.This hybrid model provides the best of both worlds: efficiency + reliability.

FMTC Subscriber Data

Regardless if you are pulling a getDeals call or a getMerchants call, you will be getting back data per your account settings in the FMTC portal. To start receiving data, you first need to become an FMTC subscriber and set up MerchantSync or manually select the merchants from whom you wish to receive the data. The getMerchants call will then return all the merchants you have selected, whether that be one or 500. From there, the getDeals call will return deals from those same selected merchants. Visit the Tech Corner articles on getMerchants and getDeals to learn how to do full or incremental calls on those APIs.

As always, our team is ready to help you! If you have any questions or concerns, feel free to contact your account manager or email us at support@fmtc.co. Curious about other FMTC technologies? Find more information on FMTC’s tools in Tech Corner:

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