# Terms

- [Complect](/terms/complect): To interleave, entwine, or braid concerns together.
- [Simple](/terms/simple): One fold or one braid; free of interleaving.
- [Easy](/terms/easy): Near at hand or familiar. Easy is relative to the person.
- [Compose](/terms/compose): To place simple pieces together without braiding them.
- [Recovery to known state](/terms/recovery-to-known-state): Restore a state whose invariants are understood instead of continuing from suspected corruption.
- [Failure isolation](/terms/failure-isolation): Limit the damage one failing subsystem can inflict on independently useful work.
- [Recovery owner](/terms/recovery-owner): The component responsible for observing worker failure and choosing what happens next.
- [Restart domain](/terms/restart-domain): The related workers whose recovery must follow their dependency relationships.
- [Restart budget](/terms/restart-budget): A bound on repeated recovery attempts before the fault escalates.
- [Rehydration](/terms/rehydration): Reconstruct the state needed by a restarted worker from retained data.
- [Error kernel](/terms/error-kernel): The critical core whose state needs a deliberate preservation and recovery decision.
- [Durable scheduled intent](/terms/durable-scheduled-intent): A recorded deadline that can be recovered when its worker loses local timers.
- [Idempotency](/terms/idempotency): Repeating an operation produces the same intended observable outcome as performing it once.
- [Effectively-once boundary](/terms/effectively-once-boundary): A processing guarantee has a defined commit boundary and does not automatically cover external effects.
- [Deterministic processing](/terms/deterministic-processing): Live processing and catch-up produce the same output from the same relevant input.
- [Event-time policy](/terms/event-time-policy): Domain rules choose event ordering and how late arrivals affect results.
- [Clean replay target](/terms/clean-replay-target): Rebuilding starts from controlled state rather than mixing retained partial state with replay.
- [Schema compatibility](/terms/schema-compatibility): Consumers can still interpret the versions of retained records they need to process.
- [Timeout](/terms/timeout): A finite bound on waiting for an answer that may never arrive.
- [Delayed retry](/terms/delayed-retry): Defer a failing operation instead of extending the caller’s wait with immediate repetition.
- [Randomized exponential backoff](/terms/randomized-exponential-backoff): Increasing delays with randomness avoid synchronized retry waves.
- [Retry budget](/terms/retry-budget): A limit on retry load, potentially shared across calls rather than only per request.
- [Deadline propagation](/terms/deadline-propagation): Downstream work respects the caller’s remaining time rather than receiving a new full allowance.
- [Cancellation propagation](/terms/cancellation-propagation): Downstream work learns that its caller no longer needs it.
- [Circuit breaker](/terms/circuit-breaker): Stateful policy stops attempts against an unhealthy operation and later probes recovery.
- [Bulkhead](/terms/bulkhead): Independent capacity protects one workload from exhaustion caused by another.
- [Resource pool](/terms/resource-pool): A bounded collection mediates access to scarce reusable resources.
- [Backpressure](/terms/backpressure): A slower consumer constrains how quickly producers can submit more work.
- [Admission control](/terms/admission-control): A service can refuse or defer new work when accepting it would worsen overload.
- [Load shedding](/terms/load-shedding): Reject new work early during overload to preserve useful service.
- [Steady state](/terms/steady-state): Every accumulating resource has a mechanism that recycles or bounds it.
- [Result cardinality bound](/terms/result-cardinality-bound): A query limits how many results it asks a caller to process.
- [Functional core](/terms/functional-core): Domain data and rules stay independent of external interfaces and process machinery.
- [Actions and calculations](/terms/actions-and-calculations): Time-dependent interactions remain separate from deterministic transformations.
- [Timeline coupling](/terms/timeline-coupling): Shared resources make concurrent action order matter.
- [Domain error](/terms/domain-error): An expected business-process outcome belongs in the domain model.
- [Applicative validation](/terms/applicative-validation): Independent checks collect their failures instead of stopping at the first one.
- [Idempotent postcondition](/terms/idempotent-postcondition): An already-satisfied desired state can be success rather than an avoidable error.
- [Exception masking](/terms/exception-masking): The layer that can recover hides details its callers do not need.
- [Exception aggregation](/terms/exception-aggregation): Failures with the same response policy reach one owning handler.
- [Error promotion](/terms/error-promotion): Reuse a larger recovery mechanism when its cost and failure frequency make that simpler.
- [Deep failure boundary](/terms/deep-failure-boundary): A small interface hides recovery mechanics without hiding caller-relevant failure information.
- [Model-based testing](/terms/model-based-testing): Generated command histories compare real outcomes with an explicit state model.
- [Precondition](/terms/precondition): A model rule identifies when a generated operation is valid.
- [Postcondition](/terms/postcondition): An observable result must satisfy the model after an operation.
- [Shrinking](/terms/shrinking): Reduce a failing input to a smaller reproducible counterexample while preserving validity.
- [Fault injection](/terms/fault-injection): Introduce a known defect to check that the test detects the promised failure.
- [Hermetic test](/terms/hermetic-test): Isolate a test from mutable external conditions to improve determinism and reproduction.
- [Four golden signals](/terms/four-golden-signals): Observe latency, traffic, errors, and saturation together.
- [Symptom-based paging](/terms/symptom-based-paging): User-visible ongoing symptoms justify paging; internal causes support diagnosis.
- [Backfill](/terms/backfill): Recover missed source data after an outage using an explicit recovery plan.
- [Transition period](/terms/transition-period): Old and new schema forms coexist while consumers migrate.
- [Backsliding prevention](/terms/backsliding-prevention): A migration prevents new dependencies on the interface being retired.