An agent can read any page on the web. It cannot read the pages it has never seen — and that is where backlinks live. Judging a domain’s authority means having crawled the web and kept the graph. Here’s how an agent buys that answer in one call instead.
POST a domain and the backlinks stall returns referring domains, referring pages, an authority rank, a spam score, broken backlinks and the composition of those links by TLD, type, attribute and country. This is the one SEO signal a page fetch cannot produce: a backlink is a link from somewhere else, so counting them requires a crawled index. Pay-per-call over x402, no key.
# A domain's link graph. Flat price in USDC over x402, no API key.
curl -s -X POST https://true402.dev/api/v1/backlinks \
-H 'content-type: application/json' \
-d '{"target": "stripe.com"}'
# → { target, observed, rank, backlinks, referringDomains,
# dofollow: { referringDomains, referringMainDomains, referringPages },
# spamScore, brokenBacklinks, firstSeen,
# composition: { tld, linkTypes, attributes, countries }, limits: [...] }A headline backlink count includes nofollow links, which explicitly tell search engines not to pass authority — so the big number overstates what actually helps. Every response carries both: the total and the dofollow subset, for referring domains, main domains and pages. An agent comparing two domains can then compare the links that carry weight rather than the ones that merely exist.
Counts come from a crawl index, and an index is a floor — links it has not crawled are not counted. A spam score is the index’s own heuristic, not a penalty from any search engine. Rather than leave an agent to know that, every response ships a limits[] field saying it in the payload. And a domain the index holds nothing for comes back as observed: false with a note — never as zero backlinks, because “we hold no data” and “this site has none” are different claims.
Backlink data usually means a subscription and a seat in an SEO suite. Here an unpaid request returns HTTP 402 with payment requirements; the agent pays USDC on Base and retries — no signup, no dashboard, no key to rotate. Want the keywords a domain already ranks for? See ranked keywords. New to the protocol? What is x402? Full reference: API docs.
It calls a backlink endpoint that already holds a crawled link graph. true402’s backlinks stall does this: POST a domain to /api/v1/backlinks and it returns referring domains, referring pages, the dofollow split, an authority rank, a spam score and the composition of those links by TLD, type, attribute and country. There is no account, no seat and no API key — the agent pays per call over x402.
Because backlinks are not on the page. A backlink is a link pointing at the domain from somewhere else on the web, so counting them means having crawled the web and kept the graph. That is the one SEO signal an agent structurally cannot compute for itself from a page fetch — which is exactly why it is worth buying rather than building.
Most backlink totals count every link, including nofollow ones that explicitly tell search engines not to pass authority. The headline number therefore overstates what actually helps. The backlinks stall returns both: the total and the dofollow subset for referring domains, main domains and pages, so an agent can reason about the links that carry weight instead of the ones that merely exist.
No, and the response says so. Counts come from a crawl index, which is a floor rather than a census — links it has not crawled are not counted. The spam score is the index’s own heuristic, not a penalty signal from any search engine. Those limits ship inside every response in a limits[] field, so an agent consuming the data sees the caveats rather than having to know them.
It is a flat price per call, paid in USDC on Base over x402 — an unpaid request returns HTTP 402 with signed payment requirements, the agent pays and retries. There is no free tier on this endpoint, deliberately: every call costs real money to serve, so a free tier would be a stranger spending the service’s balance. Cheap checks that cost nothing to serve, like the token-safety stall, do have one.