SEO data for AI agents: what keyword and search data costs per call

The short answer

Keyword volumes: in our test DataForSEO through treg returned data for 9 of 10 keywords at $0.09 a call of up to 1,000 keywords (Stackcut's own test, not a customer). our test
Live Google results: SerpApi gives 250 searches/mo, 50 searches/hour free, then Starter at $25/mo for 1,000 searches. serpapi.com
Serper sells prepaid query credits, from $0.30 per 1,000 queries on its largest package, and new accounts get 2,500 free queries once. serper.dev
OpenSEO is MIT-licensed, ships an MCP server and agent skills, and bills data per request through your own DataForSEO key. github.com

The economics

Per-call prices are what we paid in our own test (Stackcut's own test, not a customer); plan prices are from each vendor's pricing page.

Keyword volumes

Per-call rows multiply what we paid per call or per keyword in our own test (Stackcut's own test, not a customer) by the volume. Flat plans at list price billed monthly.
Keyword lookups a month	300	3,000	30,000
SE Ranking data via treg	$0.54per keyword	$5.37per keyword	$53.70per keyword
DataForSEO via treg, 1,000 keywords per call	$0.091 call	$0.273 calls	$2.7030 calls
DataForSEO via treg, 10 keywords per call	$2.7030 calls	$27300 calls	$2703,000 calls
Semrush SEO seat, for comparison	$139flat, 1 user	$139flat, 1 user	$139flat, 1 user
Moz Standard seat, for comparison	$99flat, 1 user	$99flat, 1 user	$99flat, 1 user

Live search results

Cheapest published SerpApi plan that covers the volume, billed monthly. Serper's packages are prepaid, so they aren't priced per month here.
Searches a month	250	1,000	5,000	15,000
SerpApi	$0Free	$25Starter	$75Developer	$150Production

What the free tiers really are

Option	Kind	What the free tier includes
SerpApi	Free	250 searches/mo, 50 searches/hour
Serper	One-time credit	2,500 free queries on signup (one-time), no credit card
treg		$1.00 free credit

Pick by situation

Keyword volumes for content planning: per-call data from one provider, batched, since one DataForSEO call takes up to 1,000 keywords. our test
Rankings and clicks for your own site: Google Search Console, free for a verified site, with CSV export. support.google.com
Live search results for an agent: SerpApi's free tier, then Starter at $25/mo. serpapi.com
A UI plus an MCP server: OpenSEO, self-hosted or hosted, with data billed per request. github.com

A real workflow: ask your agent

Add a data provider's MCP server or CLI to your agent, run your saved keyword list once, and keep that result as your baseline. Don't compare it number for number with an old SEO suite. the math
To price the job against the rest of your stack first, ask Stackcut: stackcut.io

choose_stack({"project": "content agent", "needs": [
  {"job": "seo_research",
   "volume": {"amount": 3000, "unit": "searches_per_month"}}]})

Evidence

Stackcut's own tests, not customers.

Tested by Stackcut · Works, with caveats2026-09-25 · Stackcut's own test, not a customer

Semrush keyword lookups → pay-per-call keyword data through treg

Question. Can an occasional keyword-volume lookup move from a Semrush seat to per-call data through treg, and do the numbers hold up?

Numbers

10 keywords from leakcheckme.com, US volumes
Coverage: DataForSEO 9/10, Serpstat 7/10, SE Ranking 6/10 (Semrush 10/10)
Cost: $0.09 per DataForSEO call (up to 1,000 keywords); SE Ranking about $0.0018 per keyword our test
Biggest gap: "delete me review" 480 (Semrush) vs 5,400 (DataForSEO)

Verdict

Good replacement for occasional keyword-volume lookups (not for rank tracking, backlinks or audits). Use DataForSEO for batches (cheapest per keyword, best coverage here) and expect different absolute numbers than Semrush.

Good fit when

You look up keyword volumes a few times a month
Relative volume is enough to prioritise content

Not a fit when

You need Semrush's own numbers (clients report in Semrush)
You rely on Position Tracking, backlinks or Site Audit

Read the receipts · Lab report on the recipe page

Fit

A good fit if

Your agent looks up keyword volumes a few times a month, or in batches. our test
Relative volume is enough to decide what to write next. our test

Look elsewhere if

Clients need Semrush's own numbers in their reports. our test
You depend on position tracking, backlinks or site audits: that's a suite job, not a per-call one. our test

Questions

Can my agent get Semrush's own data per call?

Only with a Semrush API plan: treg's Semrush endpoints need your own Semrush credential, and the API needs its own subscription. our test

Which provider is cheapest per keyword?

In our test, DataForSEO in batches: $0.09 per call of up to 1,000 keywords. SE Ranking cost about $0.0018 a keyword, with gaps on branded queries. Stackcut's own test, not a customer. our test

Why do providers disagree on volume?

They measure differently, and some merge close variants: one keyword read 480 in Semrush and 5,400 in DataForSEO in our test. Stay on one provider and compare trends. Stackcut's own test, not a customer. our test

What does SerpApi cost for 5,000 searches a month?

$75/mo on the Developer plan, which covers 5,000 searches a month at up to 1,000 an hour. serpapi.com

Next steps

Check your own stack

Get your free stack audit

Stackcut finds every software subscription in your inbox and shows what to cancel, what to pay per use, and what AI can replace, with a spec and a cost for each. Your stack audit is free and takes about 2 minutes.

Get my free stack audit

Or ask your agent

Connect the Stackcut MCP server (https://stackcut.io/mcp, no API key) and ask: “Our content agent needs keyword volumes for about 3,000 keywords a month. What's the cheapest data source?”

choose_stack({"project": "content agent", "needs": [
  {"job": "seo_research",
   "volume": {"amount": 3000, "unit": "searches_per_month"}}]})