SEO APIs
SEO APIs here score and audit sites rather than return search rankings. Open Page Rank gives domain authority scores with monthly history from Common Crawl's web graph, and CrawlGraph uses the same source to show which domains link to a site. SEO Score API audits a URL's SEO, performance and accessibility, and Crawl Readiness checks whether AI crawlers like GPTBot can read it. All are freemium with a key.
| API | Pricing | Auth | Format | Free tier | Status |
|---|---|---|---|---|---|
ASORadarApp Store and Google Play reviews, sentiment, rankings, keyword tracking, and app metadata. Developer Tools › SEO | Freemium | API key | JSON | — | Live |
Crawl ReadinessChecks if AI crawlers (GPTBot, ClaudeBot, PerplexityBot, etc.) can read a site; scores 0-100 with fixes. Developer Tools › SEO | Freemium | API key | JSON | <100/day | Live |
CrawlGraphLooks up which domains link to a given site, with authority scores, from Common Crawl snapshots. Developer Tools › SEO | Freemium | API key | JSON | <100/day | Live |
Open Page RankDomain authority scores (0-10) with monthly history, derived from Common Crawl's web graph. Developer Tools › SEO | Freemium | API key | JSON | 1k–10k/day | Untested |
SEO Score APIScores a URL's SEO, performance, accessibility, and AI-search readability across dozens of checks. Developer Tools › SEO | Freemium | API key | JSON | <100/day | Live |
ASORadarFreemiumLive
App Store and Google Play reviews, sentiment, rankings, keyword tracking, and app metadata.
API key · JSON
—
OpenAPI spec · llms.txt
Crawl ReadinessFreemiumLive
Checks if AI crawlers (GPTBot, ClaudeBot, PerplexityBot, etc.) can read a site; scores 0-100 with fixes.
API key · JSON
<100/day
llms.txt
CrawlGraphFreemiumLive
Looks up which domains link to a given site, with authority scores, from Common Crawl snapshots.
API key · JSON
<100/day
llms.txt
Open Page RankFreemiumUntested
Domain authority scores (0-10) with monthly history, derived from Common Crawl's web graph.
API key · JSON
1k–10k/day
no machine-readable spec
SEO Score APIFreemiumLive
Scores a URL's SEO, performance, accessibility, and AI-search readability across dozens of checks.
API key · JSON
<100/day
OpenAPI spec · llms.txt
Nothing matches that combination. Clear the filters and start from the category.
Choosing an SEO API
Is there a free SEO API?
Yes. Open Page Rank, SEO Score API, CrawlGraph, ASORadar and Crawl Readiness have a free tier alongside paid plans.
Which SEO APIs work without an API key?
All of them need a key or account. Open Page Rank, SEO Score API, CrawlGraph, ASORadar and Crawl Readiness give one out free when you sign up.
Can I use SEO APIs in a commercial project?
Crawl Readiness permits commercial use.
Which SEO APIs work with AI agents?
SEO Score API and ASORadar publish an OpenAPI spec for generating clients and tools.
More in Developer Tools: Mock & Test APIs · Code Execution APIs · Monitoring APIs · Web Scraping APIs · Package Registries APIs · API Directories APIs · WHOIS & DNS APIs · Search & SERP APIs · Hosting APIs