Check a dependency before installing it
Check a dependency before installing it. Give a package and, optionally, a version with its ecosystem (npm, PyPI, crates.io); the answer says whether that exact version exists, whether it is yanked or deprecated, and every advisory OSV lists against it. A version that was never published returns not_found with the real versions nearest to it. Verdicts: verified, advisory, yanked, not_found, unknown.
Answeringour last check, 2026-10-10
1 of 1checks answered this week
26 msmedian answer time
$0.02listed price per call
$0.02price it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
POST https://factstamp.agentrails.workers.dev/package
| Category | Everything else |
|---|---|
| Provider host | factstamp.agentrails.workers.dev |
| Networks | eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 1 from 1 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-10-10 | valid payment request | 402 | $0.02 | 26 ms |
Example input (from the provider)
{
"body": {
"ecosystem": "npm",
"package": "express@4.18.2"
},
"bodyType": "application/json",
"method": "POST",
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"additionalProperties": false,
"properties": {
"input": {
"additionalProperties": true,
"properties": {
"body": {
"type": "object"
},
"bodyType": {
"const": "application/json"
},
"method": {
"const": "POST"
},
"type": {
"const": "http"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"additionalProperties": true,
"properties": {
"example": {
"type": "object"
},
"type": {
"const": "json"
}
},
"required": [
"type",
"example"
],
"type": "object"
}
},
"required": [
"input",
"output"
],
"type": "object"
}