High-Cardinality Entities
How High-Cardinality Entities works in Paycux, what it is for, and the smallest setup that gets it running.
Overview
High-Cardinality Entities is part of the Paycux platform. This page explains what it does, when to reach for it, and the smallest working setup you can ship.
Everything below applies to both environments. Build and test in staging, then promote the same configuration to production without changing your code — only the API key and client ID differ.
Why FGA works well for lower-cardinality resources
Why FGA works well for lower-cardinality resources is handled by High-Cardinality Entities rather than by your application code. Paycux exposes it through the same API surface as the rest of the platform, so the client you already configured needs no additional setup.
Configuration lives in the dashboard and is versioned per environment. Change it in staging, confirm the behaviour, then apply the same change to production.
Why keep high-cardinality entities out of FGA
Why keep high-cardinality entities out of FGA is handled by High-Cardinality Entities rather than by your application code. Paycux exposes it through the same API surface as the rest of the platform, so the client you already configured needs no additional setup.
Configuration lives in the dashboard and is versioned per environment. Change it in staging, confirm the behaviour, then apply the same change to production.
What to sync vs. keep local
What to sync vs. keep local is handled by High-Cardinality Entities rather than by your application code. Paycux exposes it through the same API surface as the rest of the platform, so the client you already configured needs no additional setup.
Configuration lives in the dashboard and is versioned per environment. Change it in staging, confirm the behaviour, then apply the same change to production.
The pattern: nearest FGA-managed parent
The pattern: nearest FGA-managed parent is handled by High-Cardinality Entities rather than by your application code. Paycux exposes it through the same API surface as the rest of the platform, so the client you already configured needs no additional setup.
Configuration lives in the dashboard and is versioned per environment. Change it in staging, confirm the behaviour, then apply the same change to production.
Nested folder example
Nested folder example is handled by High-Cardinality Entities rather than by your application code. Paycux exposes it through the same API surface as the rest of the platform, so the client you already configured needs no additional setup.
Configuration lives in the dashboard and is versioned per environment. Change it in staging, confirm the behaviour, then apply the same change to production.
Fast path with JWT claims
Access tokens are JWTs signed with a rotating key. Verify them against the JWKS endpoint for your client rather than a pinned public key, so rotation never causes an outage.
1https://api.paycux.com/sso/jwks/client_01M4KXD1PZXFWGWE9ZKPCQRAQ
Cache the key set and re-fetch on an unknown key ID. Reject any token whose issuer, audience or expiry does not match what you expect.
Benefits of this approach
Benefits of this approach is handled by High-Cardinality Entities rather than by your application code. Paycux exposes it through the same API surface as the rest of the platform, so the client you already configured needs no additional setup.
Configuration lives in the dashboard and is versioned per environment. Change it in staging, confirm the behaviour, then apply the same change to production.