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Authorization and access control4 min read

The developer's guide to RBAC

The engineering questions that matter are rarely about which tool.

The engineering questions that matter are rarely about which tool. They are about which failure you are willing to own, and how loudly it will tell you when it happens.

This piece walks through how we think about it at Paycux, what we have changed our minds about, and where the sharp edges are.

Why does my app need authorization in the first place?

Why does my app need authorization in the first place? deserves its own treatment. Make the boundary explicit. When one part of the system can only talk to another through a named interface, you can change either side without a meeting; when it cannot, every change becomes a negotiation.

Make the boundary explicit. When one part of the system can only talk to another through a named interface, you can change either side without a meeting; when it cannot, every change becomes a negotiation.

Stage 1: no authorization

Stage 1: no authorization is where this gets concrete. Measure before you optimise, then measure the thing users feel rather than the thing that is easy to instrument. A p50 that looks fine while the p99 is unusable is a reporting failure, not a performance one.

Make the boundary explicit. When one part of the system can only talk to another through a named interface, you can change either side without a meeting; when it cannot, every change becomes a negotiation.

  • Name the boundary before you cross it
  • Measure what users feel, not what is easy to instrument
  • Make every retried operation idempotent
  • Write down the assumption that would invalidate the design

Stage 2: admins, and everyone else

Consider stage 2: admins, and everyone else. Make the boundary explicit. When one part of the system can only talk to another through a named interface, you can change either side without a meeting; when it cannot, every change becomes a negotiation.

Measure before you optimise, then measure the thing users feel rather than the thing that is easy to instrument. A p50 that looks fine while the p99 is unusable is a reporting failure, not a performance one.

Stage 3: n>2 roles

Stage 3: n>2 roles is where this gets concrete. Make the boundary explicit. When one part of the system can only talk to another through a named interface, you can change either side without a meeting; when it cannot, every change becomes a negotiation.

Measure before you optimise, then measure the thing users feel rather than the thing that is easy to instrument. A p50 that looks fine while the p99 is unusable is a reporting failure, not a performance one.

Idempotency is not a nice-to-have in any system with retries.

Stage 4: the great beyond

Stage 4: the great beyond is where this gets concrete. Measure before you optimise, then measure the thing users feel rather than the thing that is easy to instrument. A p50 that looks fine while the p99 is unusable is a reporting failure, not a performance one.

Make the boundary explicit. When one part of the system can only talk to another through a named interface, you can change either side without a meeting; when it cannot, every change becomes a negotiation.

Role-based authorization: basics and not-so-basics

Role-based authorization: basics and not-so-basics deserves its own treatment. Idempotency is not a nice-to-have in any system with retries. Key on an identifier the caller supplies, store the outcome, and return the same answer to the same key rather than doing the work twice.

Idempotency is not a nice-to-have in any system with retries. Key on an identifier the caller supplies, store the outcome, and return the same answer to the same key rather than doing the work twice.

Data storage: centralized vs. decentralized

That brings us to data storage: centralized vs. decentralized. Measure before you optimise, then measure the thing users feel rather than the thing that is easy to instrument. A p50 that looks fine while the p99 is unusable is a reporting failure, not a performance one.

Make the boundary explicit. When one part of the system can only talk to another through a named interface, you can change either side without a meeting; when it cannot, every change becomes a negotiation.

Where this leaves us

If there is one thing worth taking away, it is that the expensive decisions are the ones made implicitly. Making them on purpose costs an afternoon.

If you are working through the same problem and want to compare notes, the docs cover the mechanics and the console shows the behaviour on your own data.

Everything here, already built

Sign-in, enterprise SSO, directory provisioning, roles and an audit trail behind one API.

Stop reading, start shipping

The quickstart takes about ten minutes and leaves you with a working sign-in.