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Authentication

QSign uses two credentials, for two different purposes.

Every call to the signing API is authenticated with an opaque API key in the X-Api-Key header:

X-Api-Key: qsk_live_xxxxxxxxxxxxxxxxxxxx
  • Live keys (qsk_live_…) run against production — they create real documents, send real emails, and consume your plan quota.
  • Sandbox keys (qsk_test_…) run against a simulated environment — no real side effects, no quota use. Use these while developing. See Sandbox & testing.

Keys are shown once when generated and stored only as a SHA-256 hash, so a database compromise never yields a usable key. Generate, reveal-once, and rotate keys in the Developer portal.

A few account-management actions (managing keys, reading your usage) are performed with the api_admin user’s JWT (bearer token) rather than the API key. The Developer portal uses this for you; you rarely need it directly.

The API is rate-limited per caller. Responses include X-RateLimit-* headers; honor Retry-After on a 429. Monthly quota is enforced per plan — check Usage in the Developer portal or your plan’s limits.