Reference
Check backlinks online: actions, costs, parameters
A plain reference for the calls used in casework. Costs are credits, and 1 credit is $0.0001. Every call is billed once, however many rows it returns.
Actions grouped by price
| Action | Credits | Use it to |
|---|---|---|
domain, overview, stats, suggest | Free, no key | First look at a domain, its rating and headline numbers |
bulk_dr | 1 | Rate up to 2,000 domains in one call (GET domains= or a POST body) |
compare | 1 | Put up to 20 domains side by side |
top, dr_distribution, tld_breakdown | 1 | See shape: leaders, the spread of ratings, the mix of TLDs |
refdomains, backlinks | 2 | List who links to a site |
anchors, anchor_cloud, toppages | 2 | Read the words used and the pages that attract links |
intersect | 2 | Find shared referrers across 2 to 10 domains |
search | 3 | Full-text search over anchors, titles and URLs |
keyword | 3 | Find who is linked with an exact anchor |
Parameters you will reuse
Authentication is a key parameter or an Authorization: Bearer sk_... header. Keep keys out of URLs you paste into chat, because query strings end up in logs. CORS is open, so a browser tool works as well as a script. Handy.
Paging uses page and per, where per runs from 10 to 5000. Simple. A single call returns up to 1,000 rows, and deep pagination is capped at 50,000. Sorting uses sort plus order=asc or order=desc.
Put the cheap tail first. Sorting referring domains by rating ascending puts the thin domains at the top, which is where footprints show up. That one habit saves an hour.
Responses and errors
| What you get | Meaning | What to do |
|---|---|---|
ok in every response | The flag to test before reading anything else | Branch on it in your script |
_credits on keyed calls | Cost of this call and your remaining balance | Log it next to the exhibit |
| HTTP 401 | Key missing or wrong | Check the header or the key parameter |
| HTTP 402 | Credit has run out | Top up with USDT (TRC-20) on the account page |
Before you trust a response
- Check
okis true - Note the date, because the index refreshes roughly monthly
- Remember DR is round(100 · log(ref_domains + 1) / log(2·10^7)), not a third-party number
- Compare referring domains between tools, not raw backlink totals
- Archive the raw file, not just your summary
Limits, stated plainly
This is link data at a low per-call price. It does not track keywords. It does not track rankings either. Ahrefs and Semrush are fuller products for that, and Ahrefs sells API units inside subscriptions starting at $129 a month for 200,000 units.
Recipes that use these calls are in casework with curl, and unfamiliar terms are in the glossary.
Reading a response with suspicion
A response is a witness statement. It is true to the index on the day of the crawl, and silent about everything outside it. Ask what the index could not have seen: pages blocked by robots.txt, links added after the last refresh, links behind a login. If you want to check backlinks online without writing code, the checker on the home page calls the free domain action.
Cross-check one thing by hand each time. Pick a single referrer from the list, open the page and find the link. If it is there, trust the rest a little more. If not, note the date and the URL, and see the troubleshooting table.
Never let a script act on one reading. Alerting is fine, but deleting links, sending disavow files or emailing owners should wait for a human.