Backend APIs, Identity, and Safe Retries
Design request contracts that remain understandable under authentication, retries, timeouts, and duplicate delivery.
Curriculum (9 steps)
An API contract defines the meaning of operations, inputs, outputs, errors, and side effects.
An interactive concept flow for designing apis around explicit semantics, from its assumptions through the main operation and boundary checks.
Authentication answers who or what is making a request; authorization decides which actions that identity may perform on a resource.
Follow the key state changes and boundary checks involved in authentication, sessions, and authorization.
Explain the model, execution steps, complexity, and limits of authentication, sessions, and authorization.
Follow the key state changes and boundary checks involved in retries need an operation contract.
An interactive concept flow for retries need an operation contract, from its assumptions through the main operation and boundary checks.
Track the last accepted timestamp for each message and reason about state growth, ordering, and concurrent requests.