Backlinks API

A backlinks API is an interface that lets you query the links pointing at a website programmatically. Instead of opening a backlink tool and typing in a domain by hand, you make a single HTTP request from your own application and receive thousands of links as structured JSON. That is a foundational building block for teams building SEO tools, for agencies, and for companies running their own reporting infrastructure.

The Semust Backlinks API works through a single endpoint: you POST to data.semust.com/v1/backlinks and specify which report you want with the type parameter. Authentication is header-based, responses arrive in seconds, and there is no queue to wait on or task to poll for.

Backlinks remain one of the strongest signals search engines use to judge whether a page can be trusted. How many distinct domains link to you, how authoritative those domains are, whether the links are dofollow, and which anchor texts they use all bear directly on your organic rankings.

Regular analysis shows you not only the links you gain but the ones you lose. A link source that worked well for a period quietly disappearing is a common — and easily missed — cause of ranking drops. Automating the check through an API catches those changes without anyone having to look.

Total backlink count on its own is misleading. Ten thousand links from a single site are worth far less than one link each from ten thousand different sites. The referring_domains report groups links by source domain and gives an authority score, link count, dofollow ratio and first seen date for each.

The anchors report aggregates anchor texts. A healthy profile spreads across brand names, naked URLs and generic phrases; an anchor distribution concentrated on a single money keyword is a risk signal. The API returns a classification for every anchor (exact, branded, naked_url, generic, image, empty) along with its backlink count.

Pricing is row-based: a fixed fee per request plus a fee for each row returned. That differs from models where you buy credit bundles — ask for 10 rows and receive 10 rows, and you do not pay for 1,000. For applications making small, frequent queries the difference shows up clearly in the monthly bill.

A query that matches nothing still pays the base fee, because the query still ran. A repeated query is served from cache at a much lower rate. For the current price table and worked examples, see the Credits section of the API documentation.

A large domain can have hundreds of thousands of backlinks. Pulling all of them and filtering client-side is both slow and expensive. The Semust Backlinks API filters server-side: you can ask for only dofollow links, only those from domains above an authority threshold, or only those from pages in a given language.

Filters are array-shaped and combine with and and or connectors, and can be nested. Numeric fields support comparison, text fields support patterns and regex, and closed lists support in and not_in. The API's filter reference endpoint tells you which operators each field accepts.

The competitors report ranks domains whose backlink profile overlaps yours by the size of that overlap. That list often identifies the real competitors in your market more accurately than your own assumptions, because shared link sources point to similar content and a similar audience.

Pull your competitors' referring domains, compare them against your own list, and you find the sources that link to them but not to you. That difference is the most productive starting point for link building, and it can be generated automatically through the API.

The history report gives the monthly change in a domain's backlink and referring domain counts. From that series you can read the effect of a link building campaign, the loss following a penalty, or how quickly a competing site is gaining links.

The timeseries report separates links gained from links lost, by day, week, month or year. A period where net change is near zero but both gains and losses are high tells you the profile is churning quickly even though it looks static from the outside.

All you need to integrate is an API username and password, which you create from the API Access page in your account. Requests are standard HTTP POST, responses are JSON, and it can be called from any language. The documentation carries working examples for cURL, Python, Node.js, Go and PHP.

So that a timed-out request can be retried safely, there is idempotency_key support: repeating a request with the same key within 24 hours returns the stored response at no charge. Malformed requests are rejected before billing, so a wrong filter or a missing parameter never costs you anything.