Limits consumption

Ahrefs API is fully available for Enterprise plans. On all other plans, you'll still have access to a limited set of free test queries.

All requests besides free test queries and the Rank Tracker, Management, Public and some other endpoints consume API units. If an endpoint is free, you'll see a note about that on its documentation page; otherwise, it consumes units.

The units consumption per request is calculated as follows:

max(base_cost, per_row_cost * num_rows)

The base_cost of each request is 50 units. The per_row_cost is the sum of the costs of each unique field that appears in either the returned result, or in the where or order_by parameters. If a field appears in multiple parameters, it is counted once.

The default cost of a field is 1 unit. However, certain metrics are more expensive and may consume 5 or 10 units. Such exceptions are noted in the each endpoint's field description. Requests served from cache do not consume units.

Each API request indicates its units consumption behavior via the following response headers:

x-api-rows The number of rows returned.
x-api-units-cost-row The per-row units cost.
x-api-units-cost-total The overall units that the request should consume based on the number of rows and per-row cost.
x-api-units-cost-total-actual The overall units that the request actually consumed.
x-api-cache Whether the request was served from cache. One of: hit miss no_cache

info

A good way to estimate the cost of a request is to run it with a free target and check the x-api-units-cost-total field value. To display the response headers when using the curl command, you can use the -v or --verbose option.

Example 1

Consider a request to the Site Explorer - Domain rating endpoint (/site-explorer/domain-rating).

It does not accept a select, where, or order_by parameter, and it returns a single row containing two fields - domain_rating and ahrefs_rank, for a per-row cost of 2 units.

The total row cost (per-row cost multiplied by the number of rows) is less than the base cost. Therefore, this request costs the base amount of 50 units.

Example 2

Consider a more complex request to the Site Explorer - Backlinks endpoint (/site-explorer/all-backlinks), which allows the configuration of the select, where, and order_by parameters.

Suppose this request has two fields selected:

select=title,traffic

two fields in the filter expression:

where={"and":[{"field":"traffic","is":["gt",1000]},{"field":"refdomains_source","is":["gt",10]}]}

and an ordering field:

order_by=traffic:desc

Across these parameters, there are three unique fields, of which title and refdomains_source cost 1 unit each, while traffic costs 10 units. Thus, the per-row cost is 1 + 1 + 10 = 12 units.

Suppose the request returns 500 rows. Then, the total row cost (12 * 500 = 6000 units) exceeds the base cost. Therefore, the cost of this request is 6000 units.