ToolMint Citation Verify

Is this reference real? DOI / arXiv / title / free-text citation → found, canonical metadata (Crossref, arXiv), field-by-field mismatches and retraction flags. Metadata only, never abstracts.

Routes and prices

Route	Price	What it does	Parameters (* required)
`GET /verify`	$0.005	Verify one citation	`doi`, `arxiv`, `title`, `authors`, `year`, `venue`, `ref`
`POST /verify/batch`	$0.03	Verify up to 10 citations	—

Free routes: /, /health, /openapi.json, /.well-known/x402.

Try it

Not deployed yet. The URL below is the planned address. After launch, an unpaid call returns 402 with the terms in the price table.

curl -i "https://toolmint-citation-verify.toolmint.workers.dev/verify?doi=10.1016/S0140-6736(97)11096-0"

What you get

verdict: verified | mismatch | not_found | unverifiable, plus found, matchedBy, confidence
canonical record: source, doi, arxivId, title, authors, venue, year, type, publisher, url, citedByCount
mismatches[]: field, what you gave, the canonical value, severity (major/minor), note
retracted + updates[]: retractions, corrections, expressions of concern (Crossref, incl. Retraction Watch)
candidates[] (up to 3 when not found), notes[], sources[] with fetchedAt and sha256 hash, terms, cacheHit (6 h)
Abstracts are never returned.

Sources and terms

Crossref REST API (no key; metadata free to use for any purpose; some abstracts may be copyrighted, so none are returned). Polite pool via mailto; Worker paces itself at 2 requests/s per isolate.
arXiv API (metadata CC0 1.0; must not imply arXiv endorsement; one request every 3 s). Worker paces at 1 per 3 s per isolate and caps arXiv items per batch at 3.

Limits (read before relying on it)

not_found does not mean the work doesn't exist: books without DOIs, theses, case law and non-arXiv DataCite DOIs are not covered in v1.
Per-isolate pacing can't guarantee the arXiv/Crossref limits across many isolates: add a Cloudflare rate-limit rule on /verify* before volume.
Neither Crossref nor arXiv endorses this tool.

Example

GET /verify?doi=10.1016/S0140-6736(97)11096-0

Errors are not charged

Payment settles only on a successful answer. These responses are never settled:

Status	Meaning (from the OpenAPI)	Charged?
`400`	Bad input (not charged)	No
`422`	DOI registered outside Crossref (e.g. DataCite) — not verified, not charged	No
`502`	Upstream error (not charged)	No
`503`	Source busy / rate limited (not charged)	No