How I Validate API Keys Without Hitting the Database on Every Request

Free APIs come with a lot of challenges. One of the biggest ones is API key validation. If done poorly, it can lead to: performance bottlenecks unnecessary database load potential security issues Here’s how I approached this problem. Authorization and API Key Design I didn’t want to validate every API key with a database query. So I made the key self-contained . Example: Authorization: PetProjects ppk_v1_1_nonce_signature Key format: ppk_version_userId_nonce_signature Where: version — key version userId — user identifier nonce — random value signature — HMAC signature Validation Flow The validation process is split into two steps. 1. Fast Validation (No Database) First, the key is validated locally: structure check data correctness HMAC signature verification This allows us to reject invalid or garbage keys without touching the database . 2. User Check If the key is valid: we extract userId then perform a single database query Validation Code function validateApiKey ( apiKey : string )