The best SEO APIs in 2026, by the data you need

The best SEO API depends on the data you need. DataForSEO covers nearly every SEO data type on pay-as-you-go pricing. Ahrefs and Semrush make the most sense for backlinks and keyword difficulty if you already pay for the suite. SE Ranking is the closest all-in-one on API credits. SerpApi and Serper.dev are the simplest Google results APIs. Google's Search Console API and PageSpeed Insights API are free for your own site's positions and page audits. Cite42 sells keyword volume, Google positions and AI visibility checks per call, over REST and MCP, with no subscription.

Cite42 publishes this guide and is one of the APIs in it. We researched every other API from its official documentation and pricing pages on October 23, 2026, without paid test calls. If you only need search volumes, the keyword research API comparison goes deeper on that one job.

The best SEO APIs for each job

• Keyword data: DataForSEO for bulk volumes, Ahrefs or Semrush for difficulty, Cite42 for small batches per call.
• SERP and rank data: SerpApi or Serper.dev for whole results pages, DataForSEO for the lowest cost per page, Cite42 Keyword Rankings for a ready-made position per keyword.
• Backlinks: Ahrefs, Semrush, Majestic or DataForSEO.
• Site audits: PageSpeed Insights for single pages at no cost, DataForSEO On-Page or SE Ranking for full crawls.
• AI visibility: Cite42, SE Ranking or DataForSEO for brand mentions in AI answers.
• Your own search performance: the Search Console API, free for sites you've verified.

Which API covers which data

Keyword data APIs

Keyword data means monthly search volume, CPC and competition, and at the suites, keyword difficulty and intent too.

• DataForSEO returns Google Ads volumes for up to 1,000 keywords per task for $0.06 queued or $0.09 live, and its Labs API adds difficulty and intent. It's the cheapest at scale.
• Semrush and Ahrefs add keyword difficulty from their own databases. Semrush charges units per line, for example 10 units per line for live domain keyword reports, while Ahrefs charges at least 50 units per request. The Semrush API pricing guide compares the two in detail.
• SE Ranking returns volume, CPC, difficulty, intent and a monthly trend on pay-as-you-go credits.
• Google Ads API gives first-party Keyword Planner data at no per-call cost, after Google approves Basic access.
• Cite42 Keyword Research returns monthly search volume, CPC and paid-search competition for 2 to 50 keywords for $0.09 per batch, in 13 countries. It has no keyword difficulty or intent.

SERP and rank data APIs

Two kinds of API answer "where do we rank?". A results-page API returns the whole Google page and leaves the matching to you. A rank API returns your position directly, and some store the history for you.

• SerpApi plans run from 250 free searches a month to $725 for 100,000, month to month. Google stopped showing up to 100 results per page in 2025, so a top-100 check now takes up to 10 searches.
• Serper.dev costs $1.00 per 1,000 credits on its $50 pack, down to $0.30 per 1,000 on the largest, with credits valid for six months.
• DataForSEO's SERP API charges $0.0006 per page of 10 results in the standard queue and $0.002 live, so the top 100 costs $0.006 or $0.02. You don't pay for pages Google doesn't return.
• SE Ranking, Semrush Position Tracking and Ahrefs Rank Tracker store daily or scheduled positions inside a subscription and let you read them through their APIs.
• Cite42 Keyword Rankings checks Google's top 100 for 1 to 5 keywords per call in 40 countries, on desktop or mobile, for $0.09 per keyword. It returns the organic position, the position counting every block on the page, the ranking URL, every other URL of your site in the top 100, up to five competitors, the top 10 results and whether the AI Overview cites you. A keyword whose results could not be fetched is free. It runs on the REST API and in the dashboard today, and a rank tracker reruns up to 100 keywords weekly or monthly.

Every live check is one sample. Google shows different result sets to different searchers for broad keywords: in Cite42's own checks on October 20, 2026, back-to-back pulls of "best crm for small business" seconds apart showed HubSpot at 34 and then 35, and across a broader sample it moved between 17 and 35.

Backlink APIs

Backlink data needs a large crawled index, and Cite42 doesn't have one, so this job belongs to the suites and specialists.

• Ahrefs returns backlinks and Domain Rating through the API from the Lite plan, drawing on the same index as its web app.
• Semrush includes backlink reports in the Standard API, at 40 units per line in its knowledge base example.
• Majestic sells API access only on its API plan; the Lite and Pro plans don't include it. The page showed £319.99 a month when we checked, and Majestic also bills in dollars and euros.
• DataForSEO's Backlinks API costs $0.024 per request plus $0.000036 per row, so 1,000 rows cost $0.06.
• SE Ranking includes backlink data in its credit-based Data API.

Moz is the other name you'll see in backlink comparisons. We couldn't load its pricing page for this update, so it isn't in the table.

Site audit APIs

Audit APIs crawl pages and report technical problems. For one page at a time, Google's tool is enough; for a whole site, you need a crawler. Cite42 doesn't run site audits.

• PageSpeed Insights API runs Lighthouse on a URL and returns performance, accessibility and SEO findings. Google lets you call it without a key, though a key is recommended for automated use, and it plans to drop real-user field data from this API in favor of the CrUX API.
• DataForSEO's On-Page API costs $0.00015 per crawled page, or $0.0051 per page with full browser rendering. Ten thousand pages cost $1.50 at the base rate.
• SE Ranking's Website Audit API runs 115+ checks and returns a health score from 0 to 100, with issues grouped by severity.
• Ahrefs and Semrush expose their Site Audit projects through their APIs.

AI visibility APIs

AI visibility APIs report whether AI answers mention or cite a brand. Some run your own prompts live; others query a database of answers collected earlier.

• Cite42 AI Visibility runs your prompt live on ChatGPT, Claude, Gemini, Perplexity and Google AI Overviews and reports how often your brand is mentioned and in what position. It costs $0.13 per prompt on ChatGPT, Perplexity and Gemini, or $0.20 on all five, and an AI visibility tracker reruns prompts weekly or monthly.
• SE Ranking's AI Visibility API covers Google AI Overviews, AI Mode, Gemini, ChatGPT and Perplexity. Its research data refreshes monthly, and prompts you track are checked daily.
• DataForSEO's LLM Mentions API queries a database of collected answers from Google AI Overviews and ChatGPT for $0.10 per request plus $0.001 per row.
• Ahrefs includes brand visibility on AI platforms in its API.

The AI visibility API comparison covers this category in full.

Your own search data: the Search Console API

The Search Console API is the first SEO API to connect, because it's free and it's the only one with Google's own numbers for your site. Its Search Analytics method returns clicks, impressions, click-through rate and average position, grouped by query, page, country, device or date, up to 25,000 rows per request.

It has limits. It only covers sites you've verified, Search Console keeps 16 months of data, rare queries are left out for privacy, and the API returns top rows rather than every row. It also can't tell you anything about a competitor's site, which is why most teams pair it with one paid API.

How to combine SEO APIs

Most teams end up with two sources: the free Search Console API for their own site, and one paid API for everything Google doesn't share.

1. Small site or solo developer: Search Console plus Cite42 for keyword volumes, Google positions and AI visibility checks per call, from scripts or from Claude and ChatGPT over MCP. Choose DataForSEO instead if you'd rather parse raw JSON for the lowest unit price.
2. Agency already on a suite: the Ahrefs or Semrush API, so research and reports use the numbers the team sees in the web app.
3. A product with SEO features: DataForSEO or SE Ranking for breadth, priced per request or credit.
4. Search results inside your app: SerpApi or Serper.dev.

Frequently asked questions

What is the best SEO API?

There isn't one best SEO API for every job. DataForSEO covers nearly every data type on pay-as-you-go pricing, Ahrefs and Semrush suit backlink and keyword difficulty work, SerpApi is the simplest search results API, and Cite42 sells keyword volume, Google positions and AI visibility checks per call with no subscription.

Is there a free SEO API?

Yes. Google's Search Console API and PageSpeed Insights API are free, and the Google Ads API returns Keyword Planner data at no per-call cost once Google approves Basic access. Paid APIs also have free allowances: SerpApi gives 250 searches a month, Serper.dev 2,500 queries, SE Ranking 100,000 trial credits and Cite42 $1.00 of credit on verified signup.

Which SEO API has no subscription?

DataForSEO, SE Ranking's pay-as-you-go credits, Serper.dev's credit packs and Cite42 all work without a subscription. Cite42's minimum top-up is $25.00, against $50 at DataForSEO and SE Ranking and $50 for Serper.dev's smallest pack, and its balance never expires.

What is the best API for backlink data?

Ahrefs and Semrush suit teams that want backlink data next to a web app, with API access from the $129 Ahrefs Lite plan or the Semrush Business plan. Majestic sells a link-only API plan, and DataForSEO's Backlinks API charges per request, at $0.024 plus $0.000036 per row.

Can I use an SEO API from Claude or ChatGPT?

Yes, through MCP servers. DataForSEO, Semrush, Ahrefs, SE Ranking and Cite42 all run MCP servers, and Cite42's hosted server at https://mcp.cite42.dev signs in with OAuth. The SEO MCP server comparison covers the differences.

Start with the free sources

Connect Search Console first, then add the paid API that fills your biggest gap. To try Cite42 for keyword volumes, rankings and AI visibility, create a free account for $1.00 of credit, follow the API documentation or connect the MCP server, and check every price on the pricing page.