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126 questions, 454 terms and 400 topics in 20 areas.
26 results for “Idempotency Keys”
Idempotency Token Store
The durable record of which idempotency keys have been seen and what each one returned, and the component that decides whether the guarantee is real.
Idempotency
The property that performing an operation many times has the same effect as performing it once.
Idempotency Key
A client-generated unique value sent with a request so the server can recognise a retry and return the original result instead of acting twice.
AI Gateway
A shared proxy in front of model providers that centralises routing, keys, quotas, caching, logging and safety policy.
At-Least-Once Delivery
The guarantee that a message will be delivered, possibly more than once — the practical default in every distributed messaging system.
Bloom Filter Cache Guard
Placing a Bloom filter in front of an expensive lookup so that keys which certainly do not exist never reach it.
Cache Penetration
Repeated lookups for keys that do not exist, which miss the cache every time by definition and pass straight through to the store.
Consistent Hashing
A hashing scheme where adding or removing a node remaps only a small fraction of keys, instead of nearly all of them.
Encryption at Rest and in Transit
Protecting stored data from disclosure if the medium is obtained, and network data from disclosure if the path is observed — two different controls against two different threats.
Envelope Encryption
Encrypting data with a locally-generated data key, then encrypting that key with a master key held in a key management service, and storing the wrapped key alongside the ciphertext.
Hardware Security Module
A tamper-resistant device that generates and stores keys and performs cryptographic operations without the key material ever being extractable.
JWKS
A published endpoint listing an issuer's current public keys, allowing resource servers to validate token signatures without a shared secret and to survive key rotation.
Key Rotation
Periodically replacing a cryptographic key with a new one while retaining the old for decrypting existing data, so exposure from any single key is bounded.
Surrogate Key
A system-generated identifier with no business meaning, used as the primary key instead of a naturally occurring business value.
Security wants mandatory hardware keys for every login; the business says it will cost conversions. How do you resolve it architecturally rather than by picking a side?
What the interviewer is testing Whether you treat security as a fixed dial to be turned up, or as a risk proportionate design variable. Both stated positions ar
You must roll out MFA to 40,000 employees. Security wants hardware keys; the service desk fears the call volume. Design the rollout.
The framing that resolves the argument Not every identity carries the same risk, so not every identity needs the same factor. A uniform mandate is what creates
A nightly job occasionally runs twice, producing duplicate charges. The team proposes a distributed lock. What do you say?
The first response A lock will reduce the frequency and will not eliminate it , and if the team believes otherwise they will stop looking for the real fix. The
A nightly pipeline failed halfway and the retry produced duplicate rows. Walk me through fixing this properly.
The immediate problem The task appends rather than replacing its window , so a partial run followed by a retry writes some rows twice. The data is now wrong in
Design an order submission API that is safe when the client cannot tell whether its request succeeded. What exactly do you store, and when?
What the interviewer is testing Whether you know that "make it idempotent" is a design with specific failure modes, not a checkbox. The core design The client g
Three designs need distributed locks: a nightly report, a per-customer state machine, and a global config reload. For each, is a lock the right answer?
The nightly report — a lock is acceptable Purpose: efficiency . Two instances generating the same report wastes compute and possibly sends two emails, but nothi
Idempotency Keys
Client-generated keys stored atomically with the operation they guard.
Idempotency
Making an operation safe to repeat, because a client that times out cannot know.
AI Gateways
Centralised routing, keys, quotas, caching, logging and safety policy.
Cache Invalidation
Stampedes, penetration, staleness windows and versioned keys.
Relational Modelling
Normalisation, keys, constraints and the invariants a schema enforces.
Sharding Patterns
Directory versus embedded keys, logical shards and rebalancing.