Tranco API

Websitehttps://tranco-list.eu/api_documentation
CategoryLive Runtime Lookups

The Tranco API provides real-time domain ranking lookups from the Tranco research project, returning the current ranking position for any queried domain. Unlike our periodically imported Tranco list, the API reflects the very latest published ranking. We use the Tranco API on robtex.com and dns.ninja for on-demand domain popularity checks.

Source:Tranco API

What is the Tranco API?

The Tranco Top List is a research-grade domain ranking that aggregates multiple independent domain popularity sources (Majestic, Cisco Umbrella, Chrome UX Report, and others) into a manipulation-resistant composite ranking. The project, developed at KU Leuven university, publishes daily lists and provides an API for programmatic access.

The Tranco API allows querying individual domains against the current ranking without downloading and processing the entire list. Key capabilities include:

  • Single domain lookup - Query any domain and receive its current Tranco rank, or confirmation that it does not appear in the top list
  • List metadata - Retrieve information about the current list version, generation date, and configuration parameters used
  • Historical lists - Access previously generated lists by their unique list ID, enabling reproducible research
  • Custom list generation - Request lists with specific parameters (time window, source combination, list size) for research purposes

The API is freely accessible and designed for integration into security tools, network analysis platforms, and research workflows. It returns JSON responses and supports CORS for browser-based applications.

For most use cases, the API returns results quickly because it serves pre-computed rankings. The heavy computation of aggregating source lists and applying time-averaging happens during list generation, not at query time.

How We Use This Data

On robtex.com and dns.ninja, we use the Tranco API for real-time domain rank lookups when users query domains that may not be in our periodically imported snapshot. While we maintain a local import of the full Tranco list for fast bulk lookups, the API ensures we can always check a domain's current ranking.

This is particularly useful for:

  • Newly ranked domains - Domains that recently entered the Tranco Top List will appear in API queries before our next scheduled import runs
  • Rank changes - The API returns the most current rank, while our imported snapshot reflects the ranking at import time. For domains whose rank is changing rapidly, the API provides the latest position
  • Validation - Cross-checking our imported data against the live API helps ensure our import pipeline is functioning correctly

The Tranco rank is displayed alongside other domain popularity signals (Majestic Million, Cisco Umbrella, Chrome UX Report) on domain lookup pages, giving users a multi-dimensional view of a domain's internet presence.

FAQ

How is the Tranco API different from the imported Tranco list?
The imported list is a complete snapshot of the Tranco ranking loaded into our database for fast local lookups across all domains. The API queries the Tranco project's servers for the absolute latest ranking. We use the imported list for most lookups (faster, no external dependency) and the API as a real-time supplement for freshness. The difference is typically small since both reflect recent list generations, but the API is always authoritative.
Does the Tranco API have rate limits?
The Tranco project provides the API as a free service for the research community and reasonable commercial use. While they do not publish strict rate limits, the service is not designed for high-volume bulk querying. For bulk analysis, downloading the full list is the appropriate approach. We use the API selectively for individual lookups and rely on our local import for bulk operations.
Can a domain appear in the Tranco API but not in our Tranco import?
Yes, briefly. Tranco publishes new lists daily, and our import runs on its own schedule. A domain that enters the ranking in the latest daily list will be queryable via the API immediately but will not appear in our local database until the next import completes. In practice, this window is small, and rank changes between consecutive daily lists are usually minor.