A client asks for a monthly technical audit across forty sites. Half run on React. The crawler you wired up last quarter sees empty shells where the content should be, and the Lighthouse numbers come from a different script entirely. Now you are stitching together a crawler, a rendering layer and a rank source, and someone has to maintain all three.
That is the real problem behind a search for an SEO audit API. Not “which dashboard looks nicest” but which provider returns crawl data you can build on. I weighed rendering support, structured output, search coverage, agent readiness and pricing model.
Quick comparison
| Company | Best for | Pricing |
| DataForSEO | SEO software, agencies, independent consultants | mid-range, pay-as-you-go |
| Tavily | Agent-friendly web search and extraction | mid-range, subscription and pay-as-you-go |
| HasData | Scraping pipelines with no-code options | accessible, subscription |
| SE Ranking | Teams wanting a finished tool plus API | mid-range, subscription |
| Bright Data | Enterprise-scale data collection | premium, subscription |
| Oxylabs | Large proxy-backed scraping operations | premium, subscription |
| Scrapingdog | Budget scraping for small projects | accessible, subscription |
| Serper | Fast, cheap Google results for agents | accessible, pay-as-you-go |
| Brave Search API | Search grounded in an independent index | mid-range, pay-as-you-go |
How I picked these nine
I started from roughly a dozen providers that developers actually mention when they need search or crawl data through an API. Then I cut. A candidate stayed only if its documentation showed structured JSON output, a clear statement of what it crawls or returns, and an integration path beyond a bare HTTP call. Anything that was purely a proxy reseller with no parsed output fell away.
Next came pricing model and free tiers, which I read from public pages and, where a free allowance exists, tried with a few sample requests. I also read user reviews on Trustpilot and G2, looking for recurring complaints about reliability, support response and onboarding friction rather than isolated rants.
One honest limit: an audit is not only a crawler. It is rendering, rules, and often rank data next to it. So I scored providers on how much of that surface they cover, and I kept the assessment to publicly available information.
What an audit API actually has to do
Three things separate a usable audit backend from a toy.
Render JavaScript
Plain HTTP fetches miss client-side content. Browser rendering is the difference between a real crawl and a false “empty page” report.
Return structured checks
Response codes, titles and descriptions, duplicate pages, dead links. Parsed fields beat HTML you must re-parse yourself.
Sit next to search data
Audits rarely live alone. Rank tracking and SERP monitoring share the same clients, so one account for both removes glue code.
Fit agents and automation
If Claude, n8n or Make touches the data, an MCP server or native connectors save days of integration work.
The list
1. DataForSEO
Crawl audits and live search data under one set of credentials: that is the pitch, and it holds up. The On-Page API runs a site through more than 60 technical SEO checks. Think HTTP status handling, title and description tags, duplicated or non-indexable URLs, broken and internal link graphs, plus Lighthouse page speed. JavaScript and browser rendering are supported, which matters for those React-heavy client sites.
It is an API, not a finished audit product. Agencies build their own reports on top, next to rank tracking pulled from the SERP API across seven engines including Google, Bing and YouTube. For teams that need an SEO audit API alongside SERP data, DataForSEO covers both without a second vendor.
An official MCP server connects Claude, Cursor, ChatGPT and Gemini CLI, and the data also flows into n8n, Make, Zapier and Google Sheets. Nobody on your side maintains scrapers or proxies.
On G2 it sits at 4.4/5 across 16 reviews. One Trustpilot reviewer praised its cost-to-performance balance and said the team adapted quickly when Google capped results at ten per page.
Technical teams do find the API a bit complex at first. Setup rewards the engineers who read the docs.
2. Tavily
Tavily is a web access API built for AI agents. It exposes Search, Extract, Research, Crawl and Map endpoints, so an agent can find pages and then pull their content in the same workflow. It says 3M+ developers use it, and it raised a $25M Series A before becoming part of Nebius.
For audits specifically, this is a content-retrieval tool rather than a technical-SEO rule engine. Crawl and Map help with discovery. You will not get a battery of preconfigured checks like status-code and duplicate-page reports.
Billing mixes subscription and pay-as-you-go, mid-range in the market.
Strong where the agent needs to read the web. Thinner where the deliverable is a technical audit.
3. HasData
Sixty-three API endpoints and 21 no-code scrapers define HasData. It targets data pipelines and AI workloads, and it says 1.3k+ customers rely on it. Failed requests are not billed, which suits pipelines where retries are routine.
The no-code scrapers let non-engineers pull data without writing integration code. That breadth is the draw: one vendor, many sources.
As an audit backend, though, you would assemble the checks yourself from scraped output. It is a collection service, not a site-audit engine. Pricing is subscription-based and accessible.
4. SE Ranking
SE Ranking launched its first SEO tool in 2013. Legal addresses sit in London and Wilmington, Delaware, with team hubs in Kyiv, Wroclaw and Warsaw and 150+ people. It says more than a million businesses, agencies and SEO experts have used it.
The product mix is the point. Rank Tracker and Website Audit are finished tools, and an API exposes their data for integration. That makes it the odd one here: you get ready-made audit logic rather than raw crawl infrastructure.
The trade-off follows. A packaged audit is faster to adopt, but you work within its checks instead of defining your own. Subscription pricing, mid-range.
5. Bright Data
Founded in 2014 and formerly named Luminati Networks, Bright Data built its name on proxy networks. It now adds AI-powered scraping tools and refreshed datasets, and it states it serves more than 50,000 customers with over 600 team members.
On G2 it scores 4.7/5 from 334 reviews. Trustpilot shows 4.3/5 across 1020 reviews.
Scale is the strength. Coverage, unblocking and enterprise support are deep. For audit work, you are again assembling checks on top of collected pages. The premium, subscription model reflects that enterprise positioning.
Heavy machinery for a small crawl job. Worth it when volume is serious.
6. Oxylabs
Oxylabs, founded in 2015 and based in Vilnius, Lithuania, reports 15,000+ clients, 500+ employees and 177M+ proxies. In 2022 it acquired the self-service proxy platform Webshare.
G2 shows 4.5/5 from 417 reviews. Trustpilot lands at 3.9/5 across 742.
The proxy pool is the headline asset, which helps when pages block aggressive crawlers. As with Bright Data, the audit logic is yours to build. Subscription billing at a premium tier.
Reliable infrastructure, no turnkey audit.
7. Scrapingdog
Manthan Koolwal founded Scrapingdog with co-founder and CTO Darshan Khandelwal. The website launched in April 2020 and the company started in 2021.
Trustpilot shows 4.6/5 across 586 reviews. G2 is much thinner at 3/5 from only 4 reviews, so treat that figure cautiously.
It is a lean scraping API aimed at smaller projects, with accessible subscription pricing. Good for pulling pages cheaply. For a full audit workflow you would add rendering depth and rule logic elsewhere.
8. Serper
Results in one to two seconds, 2,500 free queries to start: Serper keeps the pitch narrow. It is a Google Search API sold as prepaid credits with no monthly subscription, and credits stay valid for six months.
That speed suits agents that need quick grounding. It does not crawl your site or run technical checks. Think of it as the search half of an audit stack, not the audit.
Accessible, pay-as-you-go.
9. Brave Search API
Every result comes from Brave’s own independent index, crawled and ranked by Brave, with no fallback to Google or Bing. That independence is rare. Endpoints include LLM Context for grounding, plus web, news, images, videos and Places. Brave states 150 billion queries answered and hundreds of millions of daily queries.
Because it is not Google, it shows a different view of the web. Useful for grounding, less so when the client cares about Google rankings. No site audit features. Prepaid credits, no subscription, mid-range.
Matching a provider to the job
Three situations come up again and again. Each group below names who suits which provider.
Custom audits plus rank data. DataForSEO fits agencies, SEO software makers, growth managers and independent consultants who want crawl checks and SERP results on one account, with the audit logic built their own way. SE Ranking suits agencies that would rather buy a working audit tool now and use its API to feed their own reporting.
Raw collection at scale. Bright Data suits enterprises collecting web data at high volume across many geographies. Oxylabs suits engineering teams running large proxy-backed crawls who will write their own checks. HasData suits teams building scraping pipelines who also want no-code scrapers for colleagues. Scrapingdog suits solo developers and small teams scraping on a tight budget. All four leave the audit rules to you.
Agent grounding. Tavily suits LLM app teams that need search plus page extraction inside an agent loop. Serper suits agent builders who want inexpensive, fast Google results without a subscription. Brave Search API suits teams that want search grounded in an independent index rather than a Google proxy. They answer questions; they do not grade a site’s technical health. DataForSEO also sits in this camp through its MCP server, while adding the audit side.
Before committing, ask one question of your own project: does the deliverable need rendered-page checks, or only page content? The answer cuts this list in half.
Frequently Asked Questions
What should an SEO audit API include?
A useful SEO audit API crawls pages with JavaScript rendering, returns structured results for status codes, meta tags, duplicates and broken links, and reports page speed. Parsed JSON matters more than raw HTML, because it removes custom parsing work from your pipeline.
Is an SEO audit API the same as a SERP API?
No. An SEO audit API inspects a site’s own technical health, while a SERP API returns search engine results. Many agencies need both, so providers that offer crawl data and search data on one account reduce integration and billing overhead.
How do pricing models compare for SEO audit API work?
Pay-as-you-go suits uneven workloads, since you only fund what you request. Subscriptions suit steady volume. Prepaid credits sit in between. Match the model to how predictable your audit schedule is, and check each provider’s current terms.