Validate a key

Validate a license key for a given device. This is the hot path — it is served from Cloudflare’s edge KV cache and returns in under 10ms on cache hits.

Endpoint

POST /v1/validate

Required permission: validate

Request

{
  "key":               "MYAPP-ABCD-EFGH-IJKL",
  "device_fingerprint": "sha256_of_stable_device_id",
  "app_version":        "1.2.0"
}

Field	Type	Required	Description
`key`	string	✅	The license key string
`device_fingerprint`	string	✅	SHA-256 hash of the device’s stable identifier (machine ID, hardware ID, etc.)
`app_version`	string		Your app’s version string — stored for analytics

Response — valid key

{
  "valid":            true,
  "plan":             "pro",
  "expires_at":       "2027-08-16T12:00:00Z",
  "activations_used": 1,
  "activation_limit": 3
}

Field	Type	Description
`valid`	boolean	Whether the key is valid for this device
`plan`	string \| null	The plan tier this key grants
`expires_at`	string \| null	ISO 8601 expiry; `null` for perpetual licenses
`activations_used`	integer	Number of unique devices currently activated
`activation_limit`	integer	Maximum concurrent activations allowed

Response — invalid key

{
  "valid":  false,
  "reason": "revoked"
}

Reason	Description
`not_found`	Key does not exist in this account
`revoked`	Key has been revoked
`expired`	Key has passed its `expires_at` date
`activation_limit`	Key has reached its activation limit on other devices

Caching behavior

Lizen caches validation responses in Cloudflare KV with a 60-second TTL. On cache hits, the request never reaches the origin — latency is under 1ms at the nearest PoP.

Cache is invalidated immediately on revocation. After revoking a key, all subsequent validate calls return valid: false within milliseconds.

Example

import { Lizen } from '@lizen/sdk';

const lizen = new Lizen({ apiKey: process.env.LIZEN_API_KEY! });

const result = await lizen.validate({
  key:               storedLicenseKey,
  deviceFingerprint: getMachineId(),
});

if (!result.valid) {
  // result.reason: 'not_found' | 'revoked' | 'expired' | 'activation_limit'
  showLicenseError(result.reason);
  app.quit();
}

Rate limits

Plan	Calls/day
Free	500
Hobby	10,000
Starter	50,000
Growth	200,000
Enterprise	Unlimited

Exceeded rate limits return 429 with a retry_after value in seconds.