Verify the citations in any document over HTTP

The citation verification API takes a document and the sources it cites and returns a verdict for every citation, a quote-integrity result for every quoted span, a retraction status for every DOI, and an independence audit over the source list. It is built for developers and publishers who need a machine check before something goes out, and it works on documents Hyperresearch did not write: your own draft, your customer’s draft, or the raw output of another model’s deep research mode.

It is the same code that gates Hyperresearch’s own reports. Nothing softer is offered to outside documents.

Four checks over one request

POST /v1/verify/report runs all four and applies the ship-gate rules. Four narrower endpoints run one check each: POST /v1/verify/citations, POST /v1/verify/quotes, POST /v1/verify/retractions and POST /v1/verify/independence. The retraction endpoint takes a bare dois array and needs no document at all, which is the cheapest way to sweep a bibliography.

What a receipt contains documents every field the checks return.

Request shape

All five creation endpoints take the same JSON body. Every field is optional at the schema level; which ones you need depends on the check.

Sources get in three ways. Send text and nothing is fetched, which is the cheapest path and the way to verify against a private document. Send url and the page is fetched through the same fetch ladder a research run uses. Send note_id and the source is read from your workspace vault.

An optional Idempotency-Key request header is accepted, so a retried submission does not create a second billable job.

Response shape

Creation returns 202 with the job, not the result:

GET /v1/verify/{id} returns id, status, pairs_total, pairs_llm, price_cents, usage_event_id, created_at, finished_at and error. pairs_total and pairs_llm are the two numbers that matter operationally: how many citation-sentence pairs the document contained, and how many of them reached the model tier and are therefore billable.

GET /v1/verify/{id}/result returns id, status, receipt_url and receipt. The receipt is inline; receipt_url is an HMAC-signed reference to the durable copy in storage and expires after about an hour.

A verification in three calls

curl -sS https://api.hyperresearch.ai/v1/verify/report \
  -H "Authorization: Bearer <YOUR_API_KEY>" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: draft-4821-pass-1" \
  -d '{
    "document_md": "Installed battery storage reached 42 GW in 2024 [1], and capacity grew 60% year over year [2].\n\n## Sources\n1. Market report\n2. Trade press summary",
    "sources": [
      { "n": 1, "title": "Market report", "text": "Installed capacity stood at 42 GW at the end of 2024." },
      { "n": 2, "url": "https://example.org/storage-2024", "doi": "10.1000/example.2024.001" }
    ],
    "sample": "all"
  }'

curl -sS https://api.hyperresearch.ai/v1/verify/abc123 \
  -H "Authorization: Bearer <YOUR_API_KEY>"

curl -sS https://api.hyperresearch.ai/v1/verify/abc123/result \
  -H "Authorization: Bearer <YOUR_API_KEY>"

Poll the status endpoint until status is terminal, then read the result. A 200-citation report with around 60 pairs reaching the model tier typically returns in under a minute; a 40,000-word document with hundreds of citations runs as a background workflow and delivers a verify.done webhook.

What it costs

Verification is billed by the pair that has to be read. Pairs that clear the mechanical triage are free, and quote integrity, the retraction sweep and the independence audit are included. The status response reports pairs_total and pairs_llm, so the bill is reconcilable against what was actually read, and price_cents on the same response is the exact amount charged.

The workspace spend cap applies to verification the same way it applies to runs. See pricing for plans and caps.

Limits

• The request schema caps document_md at 8 MB.
• Up to 500 sources per request, each source text up to 2 MB.
• Up to 100 DOIs in a dois sweep.
• Citation extraction covers numbered [N] and wikilink [[note-id]] styles. Author-year and footnote styles are not supported today.
• Text only. Figures, tables published as images, and audio are out of scope.
• Submitted documents and sources are deleted 7 days after the job finishes unless you sent persist: true. The receipt is kept.

The scope you need is verify

Every endpoint on this page requires an API key or agent connection carrying the verify scope. Scopes are per key, set when the key is created, and visible in the console. An agent connected over MCP gets read-only scopes by default; verify is a metered action and has to be granted separately, because it spends money.

How this differs from reference checkers

Most citation-checking tools answer one question: does this reference exist. They take a reference list, resolve the DOI, compare the metadata against Crossref, PubMed, arXiv or OpenAlex, and tell you whether the paper is real and whether the author, year and title match. SourceVerify does this through an API with per-field labels. GPTZero’s hallucination detector does it for students and educators across a large scholarly index. A dozen free web tools do the same thing with a paste box. That check is genuinely useful, and a fabricated reference is a real failure mode worth catching.

This API answers four different questions, and existence is not one of them:

• Does the cited source’s text support the sentence that cites it. This requires reading the source body, not its metadata record.
• Is every quoted span intact. A real paper, correctly cited, can still be quoted with words changed or dropped.
• Has the paper been retracted. A retracted paper resolves perfectly and matches its metadata exactly, so a metadata check cannot see it. The retracted status comes from OpenAlex’s is_retracted flag. The Crossref fallback, used when OpenAlex has no record, does not currently detect retractions. Expressions of concern are in the schema but are never produced today. Retraction-aware research has the detail.
• Are these citations independent. Five citations to five URLs carrying the same wire story are one voice, and a metadata check has no reason to notice.

Scite’s Smart Citations is a third thing again, and worth knowing about for a different job: it classifies how the published literature cites a paper, supporting or contrasting or mentioning, across millions of citation statements. That tells you how a paper has been received. It does not tell you whether your sentence is supported by the source you attached to it. The two are complements, not substitutes.

If your failure mode is a fabricated reference, a metadata checker is the cheaper tool and you should use one. If your failure mode is a real reference attached to a sentence it does not support, that is what this API is for.

Try it without an account

The public demo at /verify runs the same four checks on a pasted document, three checks per day per visitor, gated by Cloudflare Turnstile and no account or card. It exists so you can see real verdicts on your own text before deciding anything.

The demo is deliberately small: up to 20,000 words of document, up to 8 sources, up to 10 DOIs, and up to four pairs read per submission, with the receipt kept for 24 hours and three submissions per network per day. Vault note ids are refused outright, because an anonymous caller must not be able to read a workspace. Everything above those limits is the API on this page.