Stack Facts compared with the free sources

Updated 2026-10-12. Every Stack Facts answer comes from free, openly licensed sources. If you need a lookup now and then and are happy to parse the source yourself, use the source directly. Stack Facts is for agents that need one checked, signed answer per call.

Question	Free from the source	Stack Facts adds
Is this product version end-of-life?	endoflife.date: release cycles with their dates	The status of each cycle on the answer date (supported, security-only, eol or unknown); up to 50 product versions in one call (POST /v1/eol/check).
Is this container image end-of-life?	endoflife.date: release cycles per product, not per image tag	The image tag or whole FROM line read for you (node:18-alpine3.19, python:3.12-slim-bookworm, ubuntu:jammy, gcr.io/distroless/nodejs20-debian12): the runtime, Java and base OS it names, each with its cycle and status, and the worst of them; a version older than every listed cycle of an end-of-life line is eol; when the image product itself did not match, the headline is unknown unless a matched part is eol or security-only, and complete says whether every part matched (GET /v1/eol/image).
Is this CVE actively exploited?	CISA KEV: the whole catalog as one JSON file	One CVE, or up to 100 in one call (POST /v1/kev/check), with the required action and due date; what changed since a snapshot (GET /v1/kev/changes).
What does this LLM cost, and which is cheapest?	LiteLLM and models.dev: price and context lists	The two sources merged into one record per model, with a flag where they disagree; the cheapest models for your constraints (POST /v1/models/cheapest); a cost estimate; a change feed.
Does this package version have known vulnerabilities?	OSV.dev: advisories per ecosystem, as bulk files and a query API	The advisories affecting each version, with fixed versions and a CISA KEV flag; up to 50 purls in one call (POST /v1/osv/check), or with the rest of the stack (POST /v1/stack/check).

On every answer

A snapshot id and the time the source data was fetched, so the answer is dated.
An Ed25519 signature over the snapshot manifest (EOL, KEV and Models), checkable with the keys at /v1/keys.
One call for a whole stack: POST /v1/stack/check takes up to 50 product versions, 50 packages (purls) and 100 CVEs ($0.012).
Container images: GET /v1/eol/image?image=node:18-alpine3.19 answers the end-of-life status of the runtime and base OS the tag names ($0.005).
What changed since your last check: POST /v1/stack/watch answers a stack, then on each re-check with its signed token only what changed (an end-of-life date passed or near, a new CISA KEV listing, a new OSV advisory); no watch state is stored ($0.012 a call).
Open-source packages: POST /v1/osv/check takes up to 50 purls and answers the OSV.dev advisories for each version, with fixed versions and a CISA KEV flag ($0.005).
Paid per call in USDC over x402: no account, no API key. Errors are never charged.

Free samples first: /v1/try/eol, /v1/try/kev, /v1/models/preview. Licences and attribution: /licences.

Data is provided as is, without warranty of any kind. Payments are final. Every dataset is normalised (modified) from the sources named here, and no source endorses this service.