Resolve a DOI, PubMed ID, PMCID, ISBN, ISSN, arXiv ID, or ADS bibcode to a formatted citation or a bibliography file with a single HTTP call. Free for light use, no key required, deterministic output — built for scripts, reference managers, and AI agents.
Send one identifier (or many, one per line) to /api/format and get back a formatted citation. No signup, no key for light use:
curl -sS -X POST "https://scholar-sidekick.com/api/format" \
-H "Content-Type: application/json" \
-d '{"text":"10.1038/nphys1170","style":"apa"}'Full endpoint reference, parameters, and response shapes are in the API documentation. Machine-readable spec: OpenAPI.
Point the API at a DOI and it returns the full bibliographic record — who wrote it, where it was published, when, and what other identifiers it carries. The same endpoint resolves PubMed IDs against PubMed, preprints against arXiv, books against OpenLibrary, and astrophysics records against NASA ADS, so you don’t have to special-case each registry. Not sure what kind of identifier you have? The identifier detector handles mixed and messy input.
Scholar Sidekick is also an open-source MCP (Model Context Protocol) server, so Claude, ChatGPT, Cursor, and custom agents can call it as a tool with no glue code. Whether you call the REST endpoints or the MCP tools, the output is deterministic and version-pinned: the same input returns the same bytes, which matters when an agent’s citations have to be reproducible and auditable. See the engineering principles for how provenance and versioning are surfaced.
You can — and for raw metadata, you should. But Crossref and OpenAlex hand you a metadata record, not a citation. To get from a DOI to a finished reference you still have to detect the identifier type, normalise it, run a CSL engine for the style you want, and write each export format by hand — then repeat that for PMIDs, ISBNs, arXiv IDs, and the rest. Scholar Sidekick does all of that behind one endpoint, across eight identifier types, with deterministic output and built-in retraction, open-access, and fabrication checks. It is a thin, transparent layer over the same authoritative sources — not a replacement for them.
Free for light, anonymous use with no key. A free key raises the rate limit; paid tiers add a higher monthly quota and are billed through RapidAPI. Every tier has the full feature set — only the request quota and per-IP burst scale with price. See the full pricing and rate-limit tiers or the machine-readable /pricing.md.
Yes. The Scholar Sidekick citation API is free for light, anonymous use with no key — you can call it from a script or an AI agent immediately. A free API key raises the rate limit, and paid tiers add a higher monthly quota; every tier has the full feature set.
A DOI resolver API takes a DOI (or other scholarly identifier) and returns its bibliographic record — title, authors, journal, year, and identifiers. Scholar Sidekick resolves DOI, PMID, PMCID, ISBN, ISSN, arXiv ID, and ADS bibcode against the appropriate registry and returns clean CSL-JSON or a formatted citation.
Yes. Scholar Sidekick is a REST API and an open-source MCP (Model Context Protocol) server, so Claude, ChatGPT, Cursor, and custom agents can call it directly. Output is deterministic and version-pinned, so the same input returns the same bytes — important when an agent's output has to be reproducible.
Eight identifier types: DOI, PMID, PMCID, ISBN, ISSN, arXiv ID, ADS bibcode, and WHO IRIS URL. Vancouver, APA, AMA, IEEE, and CSE are built in, plus any of 10,000+ Citation Style Language (CSL) styles, including Chicago, Harvard, MLA, Nature, BMJ, and Lancet.
Crossref and OpenAlex return raw metadata; you still have to detect the identifier type, normalise it, run a CSL engine, and write each export format yourself. Scholar Sidekick does detection, normalisation, formatting, and export behind one endpoint, across eight identifier types, with deterministic output and built-in retraction, open-access, and fabrication checks.
No key is required for light use. For a higher rate limit, create a free first-party key (prefixed ssk_) at /account and send it as an Authorization: Bearer header. Paid/managed tiers are available through the RapidAPI gateway. Scholar Sidekick does not use OAuth.