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Get $100 free
ContentinGet $100 free

798.5 billion backlinks indexed

Back link checker for a headless CMS release flow

Call it from the webhook your CMS already fires on publish. You get JSON from our own link index of 181 million domains, free overview calls and a $100 credit that needs no card.

Get $100 freeRead the webhook runbook
  • overview, domain, stats: free, no key
  • 2 credits for backlinks and refdomains
  • Fits a publish webhook or a CI step
GET /api.php?action=domainJSON

$ curl "https://contentin.app/api.php?action=overview&q=example.com&key=sk_live_..."

Who it is for

Where a back link checker fits in a CMS publish hook

Publish is an event. Contentful, Sanity and Strapi can each post a webhook when an entry goes live. A small function behind that hook can ask our API one question about links before your build or cache refresh runs.

We built Contentin for teams that already run that kind of flow, so nobody has to open a dashboard. The overview call is free and needs no key, which means you can wire it into a staging hook this afternoon and read the JSON before you spend a credit.

Think of the check as a gate, not a report. Short memory helps. It reads a link graph that refreshes roughly once a month, so it tells you whether a domain is known and how it scores, not whether a link went live yesterday. Plan for that gap, and start with the webhook runbook.

What answers your call

domains in our own link index
181,132,097
backlinks indexed, refreshed about monthly
798.5 billion
price of one credit
$0.0001
credits in the $100 sign-up gift
1,000,000

Our read

A gate for links, not a crystal ball for rankings

Use the data to warn an editor, tag an entry or feed a nightly sweep. It cannot promise where a page will rank, and it will not replace a keyword suite when that is what you need.

  • Good for pre-publish sanity checks and nightly sweeps
  • Not a keyword or rank tracker: Ahrefs or Semrush are fuller there
  • Monthly refresh, so read results as a trend and not as a live feed

Compare

What one publish costs at three sizes

Example volumes for planning. They are not customer data.
SitePublishes a monthCalls per publishCreditsDollars
Docs site2001 refdomains (2 credits)400$0.04
Product marketing site3,000overview (free) + 1 backlinks (2 credits)6,000$0.60
Editorial network50,000refdomains + backlinks (4 credits)200,000$20.00

A publish handler, as a sketch

The field names on the entry are invented for this sketch. Replace them with your own content model.

js
// runs when the CMS reports that an entry went live
export async function onPublish(entry) {
  const host = new URL(entry.fields.canonicalUrl).hostname;
  const res = await fetch(
    `https://contentin.app/api.php?action=overview&q=${host}`
  );
  const data = await res.json();
  if (!data.ok) {
    console.warn('link check failed, publish continues');
    return null;
  }
  return data; // keep only what you need in your own field
}

What it is for

What the integration gives a release flow

Four things matter once the hook exists: what is free, what is cheap, what runs in bulk and how failures look.

Free calls for the gate

domain, overview, stats and suggest cost nothing and need no key. A gate that only reads those never touches your balance.

Cheap rows for the audit

backlinks and refdomains cost 2 credits a call and return up to 1,000 rows. The cost table shows how that adds up.

One batch for the nightly sweep

bulk_dr takes up to 2,000 domains per call for 1 credit. Thirty nights of it costs 30 credits, or $0.003.

Plain HTTP, readable failures

A missing or bad key returns HTTP 401 and an empty balance returns 402. The post-mortem shows why that matters.

FAQ

Questions from teams wiring this in

What is a back link checker and where does it go in a headless CMS?

It is a lookup that returns the links pointing at a domain or page. In a headless stack it usually sits behind a publish webhook or a CI step, runs once per entry, and writes a short note back to the entry.

Can I call it from a Contentful or Sanity webhook?

Yes. Both can post to a URL you own, and your function then calls our REST API with a key in the query string or a Bearer header. CORS is open, so a browser-side preview can call the free actions as well. Retries are on you, so make the handler safe to run twice.

How much does a link check add to each publish?

Nothing if you stay on the free actions. A backlinks or refdomains call is 2 credits, which is $0.0002. At 3,000 publishes a month with one such call each, that is $0.60.

Why does a link I built last week not show up?

Our index refreshes roughly once a month, so recent links can be missing. Treat results as a trend. If you need daily-fresh crawl data, a larger suite such as Ahrefs or Semrush covers that better than we do.

What happens when my balance runs out during a release?

The API answers HTTP 402. Decide in advance whether your gate fails open or closed. We suggest open for link checks: log it, skip the check and let the editor publish.

Is there a free option I can test on staging?

Yes. domain, overview, stats and suggest are free and need no key, and signing in with Google adds $100 of credit without a card, which is 1,000,000 credits. Nothing else is needed to start.

Does this replace Ahrefs or Semrush?

No. Those are fuller products for keywords, rank tracking and daily-fresh crawling. Contentin does one narrower job: link data by the call, at a low price, in JSON you can drop into a pipeline.