Call before installing packages suggested by a language model
Call before installing packages suggested by a language model. Returns, for each npm or PyPI package name, whether it actually exists in the registry, whether it is deprecated or yanked, and — when the name is not found — the closest real package names. Catches hallucinated dependencies (slopsquatting) before an agent installs them. Never inspects package contents and never returns a safety verdict.
50000 (raw units)
price
2
calls / 30d
2
unique payers
2026-09-17
updated
Provider
preflight402.com · discovered, not yet claimed by its owner
Payment (x402 accepts[])
[
{
"scheme": "exact",
"network": "eip155:8453",
"payTo": "0xB9Db3966C7F18283624C97E860a84CEf7f9ba607",
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"amount": "50000",
"maxTimeoutSeconds": 300
}
]Output schema
{
"bazaar": {
"info": {
"input": {
"body": {
"ecosystem": "npm",
"packages": [
"left-pad"
]
},
"bodyType": "json",
"method": "POST",
"type": "http"
},
"output": {
"example": {
"checked_at": "2026-09-02T21:40:00Z",
"ecosystem": "npm",
"results": [
{
"exists": false,
"name": "jscodeshift-react",
"official_url": "https://www.npmjs.com/package/jscodeshift-react",
"verdict": "not_found"
}
]
},
"type": "json"
}
},
"schema": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"additionalProperties": false,
"properties": {
"ecosystem": {
"enum": [
"npm",
"pypi",
"crates"
],
"type": "string"
},
"packages": {
"items": {
"maxLength": 214,
"minLength": 1,
"type": "string"
},
"maxItems": 20,
"minItems": 1,
"type": "array"
}
},
"required": [
"ecosystem",
"packages"
],
"type": "object"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}
},
"builder-code": {
"info": {
"s": [
"cdp_sdk_server"
]
},
"schema": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"additionalProperties": false,
"properties": {
"a": {
"description": "App builder code",
"pattern": "^[a-z0-9_]{1,32}$",
"type": "string"
},
"s": {
"description": "Service builder codes",
"items": {
"pattern": "^[a-z0-9_]{1,32}$",
"type": "string"
},
"maxItems": 11,
"type": "array"
},
"w": {
"description": "Wallet builder code",
"pattern": "^[a-z0-9_]{1,32}$",
"type": "string"
}
},
"type": "object"
}
},
"eip2612GasSponsoring": {},
"erc20ApprovalGasSponsoring": {}
}Use it
curl
curl "https://preflight402.com/v1/deps/check" # -> 402 Payment Required, accepts[] lists how to pay # retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid
JavaScript
const res = await fetch("https://preflight402.com/v1/deps/check");
if (res.status === 402) {
const { accepts } = await res.json();
// pay one of accepts[] via an x402 client, then retry with the payment header
}Python
import httpx
res = httpx.get("https://preflight402.com/v1/deps/check")
if res.status_code == 402:
accepts = res.json()["accepts"]
# pay one of accepts[] via an x402 client, then retry with the payment headerMachine-readable
Everything on this page is also available as clean JSON at /resources/12392.json, and this resource appears in /discovery/resources and /discovery/search.