What matters when an agency buys an SEO API
Three things decide the real cost, and none of them is the headline plan price.
- Billing model. Units per request, credits, rows or a prepaid balance each behave differently when you add clients.
- What is included. Some APIs come with an app and white-label reports, others are API only and you build the dashboard yourself.
- Limits. Rows per request, monthly caps, expiry of purchased units and the plan needed to unlock the API at all.
Before committing, take three real client domains, pull the data you actually use each week, and price that workload on each vendor. Plan pages alone will mislead you.
SEO API comparison for agencies
| Provider | What it costs | How usage is billed | Best for |
|---|---|---|---|
| Ahrefs API v3 | Lite 129 USD per month with API and MCP, Enterprise 1 499 USD per month annual for uncapped API | Units per request, at least 50 units, rows times fields, pay-as-you-go units at an unpublished rate | Teams that need the largest independent link index |
| Semrush API | Top tier plan plus unit packs, packs from 2 million units, price unpublished | Units per line of each report, historical data costs more | Teams already working in Semrush reports |
| DataForSEO | Prepaid balance, backlinks live mode 0.024 USD per request plus 0.000036 USD per row | Per request and per row | Developers building their own interface at high volume |
| Majestic | API plan 379.99 EUR per month | Subscription with API limits | Link-only research and trust metrics |
| SE Ranking | Standalone API from 45 EUR per 250K credits, 50 USD minimum deposit | Credits | Agencies that want API-only data with automation hooks |
| SeoData | Agency 299 USD per month or 149 USD per month yearly, 100 000 rows; Enterprise 999 USD or 499 USD yearly, 1 000 000 rows | Rows returned, one record is one row | Agencies that want app, white-label reports and API on one forecastable bill |
Ahrefs API for agencies
Ahrefs offers the API on paid plans from Lite and charges units per request: the larger of 50 units or the per-row cost times rows returned. Lower plans cap rows per request, and extra units are billed pay-as-you-go. It is the right choice when link index depth is the deciding factor. It gets expensive when many client dashboards refresh often. Our Ahrefs API pricing breakdown works through a 20 client example.
Semrush API for agencies
Semrush gates the Standard API behind its top plan and starts every account at zero units. Units are charged per line, and its own example prices 10 units per line of current organic keywords and 50 per line of historical data. Great depth, but you must estimate every report before you call it. The details are on our Semrush API pricing page.
DataForSEO, Majestic and SE Ranking
DataForSEO has no subscription. You deposit a balance and pay per request, which makes it the cheapest route at very high volume, but you build the dashboard, the reports and the client portal yourself. Majestic is link data only and its API plan is a separate, higher tier. SE Ranking sells API credits from 45 EUR per 250K credits with a 50 USD minimum, and it is a solid standalone option for agencies that already use its tracking.
SeoData API for agencies
SeoData counts rows, so a request for 200 backlinks uses 200 rows whatever fields you ask for. Agency includes 100 000 rows a month, 10 seats, 25 projects and white-label PDF reports. The same data is in the app, so account managers and developers work from one source. It covers domain overview, backlinks, referring domains, keywords, keyword gap, audit issues and daily positions. The trade-off is index size: Ahrefs and Majestic have longer link histories, so compare on a few client domains first. Endpoints are listed on the SEO API page, and the backlink API comparison goes deeper on link data.
A 20 client agency priced on each model
Say each client needs a weekly overview, 100 backlink rows and 200 position rows, about 6 000 rows a week and 26 000 a month. On SeoData that fits inside Agency with 74 percent of the quota unused. On unit models the same pulls depend on field choices and on report rates, so you have to price each endpoint first. On DataForSEO the request fee dominates when calls are small, so batching matters. Agencies with a few hundred clients often end up on Enterprise or on DataForSEO, depending on whether they need an app. Onboarding a new client also means checking who you are working with, and a quick company background check on a new client takes a minute before the contract goes out.