Clearance
Trademark clearance as an API call
Naming tools, registrars, and legal software all hit the same wall: is this name already taken as a trademark? The clearance endpoint answers with ranked similar marks and a risk level — in one request.
Last updated July 2026
One request, ranked conflicts
Screen “nikee” for apparel (international class 25):
curl "https://api.markbase.co/clearance?mark=nikee&class=25"
The response ranks existing marks by similarity, each with a score and risk level:
{
"mark": "nikee",
"class": "025",
"highest_risk": "high",
"matches": [
{
"serial_number": "72414177",
"word_mark": "NIKE",
"owner_name": "Nike, Inc.",
"status_code": "800",
"international_codes": ["025"],
"similarity": 0.85,
"risk": "high"
}
]
}highest_risk makes the integration trivial: a name generator can drop anything above “medium” without inspecting individual matches.
Why class scoping matters
Trademark rights are tied to goods and services. DELTA coexists as an airline, a faucet maker, and dental insurance because they occupy different classes. Screening without a class produces noise; passing class=25 (or whichever of the 45 international classes fits your use) keeps results to marks that could actually block you. The /classes endpoint lists them all.
Where it fits
Name generators — screen every AI-suggested name before showing it, so users never fall in love with a taken mark.
Domain registrars — flag likely trademark conflicts at search time, before the customer buys a domain they can't safely use.
Legal intake — pre-qualify clearance requests so attorneys start from a candidate list instead of a blank search box.
AI agents — a deterministic tool call that grounds “is this name available?” in the actual USPTO register instead of a model's guess.
What it is — and isn't
The endpoint is a fast first-pass filter over the federal register. It doesn't cover state trademarks, common-law rights, or the legal analysis of confusion — no API does. Treat a clean result as “worth pursuing,” not “cleared,” and put a real attorney at the end of the funnel for names you intend to use.
Screen a name right now
No key needed on the free tier — try your own brand name against the live register.
Frequently asked questions
What is a trademark clearance search?
Before adopting a brand name, you check whether confusingly similar marks already exist for related goods or services. Attorneys do a deep version of this; the clearance API automates the first pass so obviously conflicted names die early.
Is this legal advice?
No. The API is a screening signal that surfaces similar existing marks. Likelihood-of-confusion is a legal judgment that depends on factors an algorithm can't weigh — for a name you're serious about, have a trademark attorney run a full clearance.
How is similarity scored?
Candidate marks are pulled from a fuzzy search over the full USPTO index, then ranked by string similarity to your proposed mark, each with a similarity score and a risk level. Scoping by international class narrows results to the goods and services that actually matter.
Can I screen names in bulk?
Yes — it's one GET request per name, so a name generator can screen every candidate it produces. The Scale plan's 1M requests/month is sized for exactly that.