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275 questions, 991 terms and 600 topics in 30 areas.
60 results for “Consumer-Driven Contracts”
Consumer-Driven Contract
A contract derived from what consumers actually use, published to the provider, and verified in the provider's own build.
Consumer Contract
A machine-readable record of exactly which parts of a provider's response one consumer relies on, generated from that consumer's own tests.
Event Notification vs Event-Carried State
Whether an event carries only the fact that something happened, or also the data a consumer needs to act on it.
Provider Verification
The provider-side stage that replays every consumer's recorded expectations against the real implementation.
Access Pattern Driven Modelling
Designing the data model from the queries the application must serve, rather than from an abstract normalised representation of the entities.
Consumer Group
A set of consumers that cooperatively read one stream, with each partition assigned to exactly one member, so the group collectively processes every message once.
Consumer Lag
How far behind the newest record a consumer is, expressed in time rather than in message count, and its rate of change.
Domain-Driven Design
Modelling software around the business domain, with boundaries drawn where the language of the business changes.
Event-Driven Architecture
A style in which components communicate by emitting and reacting to facts about what happened, rather than by calling each other.
Event-Driven Integration
Systems integrating by publishing and consuming events rather than by calling each other's APIs.
Internal Consumer SLO
A reliability commitment made to teams who cannot switch supplier, which is why it must be measured from their side rather than from the platform's.
Salesforce's Metadata-Driven Multi-Tenancy
Salesforce serves every customer from shared infrastructure with a single physical schema, storing customer-specific data structures as metadata rather than as separate tables.
Backward Compatibility
The property that a new version of a producer continues to work with clients written against the old version.
Bidirectional Contract
A contract verified from both sides — the consumer's expectations and the provider's actual behaviour — without either running the other's tests directly.
Broker and Mediator Topology
Two ways of organising an event-driven system — components reacting independently to a shared channel, or a central component coordinating a defined sequence.
Competing Consumers
Multiple identical consumers reading from one queue, so throughput scales with consumer count and work is distributed automatically.
Contract Verification Gate
A provider's pipeline stage that replays every consumer's recorded expectations and fails the build if any would break.
Dead Letter Queue
A separate queue that receives messages which could not be processed after a set number of attempts, so they neither block the consumer nor disappear.
Dynamic Secrets
Credentials generated on demand for a specific consumer with a short lease, rather than stored, shared and rotated periodically.
Event Sourcing
Storing the full sequence of state-changing events as the system of record, and deriving current state by replaying them.
Event Versioning
Evolving event schemas without breaking consumers that may read messages written months earlier.
Golden Signals
The four measurements that cover most of what matters for a request-driven service: latency, traffic, errors and saturation.
Leaky Abstraction Cost
What a consumer pays when a platform abstraction hides a mechanism they must nonetheless understand to diagnose or tune it.
Message Queue
A store that holds messages until a consumer processes them, decoupling producer availability and rate from consumer availability and rate.
Offset Management
How a consumer records its position in a stream, and the decision that determines whether processing is at-least-once or at-most-once.
OpenAPI
A machine-readable specification format for HTTP APIs, from which documentation, clients, servers, mocks and validation can be generated.
Partition Assignment
The mapping of partitions to consumer instances that determines parallelism, ordering guarantees and what happens when the consumer set changes.
Paved Road Telemetry
Instrumenting the platform's own usage — where teams succeed, where they stall, where they leave — so its roadmap is driven by evidence.
Poison Message
A record that a consumer cannot process and cannot skip, which halts its partition entirely until someone intervenes.
Producer Obligation
What a data contract binds the producing team to do, and — crucially — what happens in their pipeline when they are about to break it.
Prop Interface Stability
The commitment a component makes about its props, slots, events and emitted structure — including the parts consumers depend on that were never intended as interface.
Provisioned vs Serverless Capacity
Paying for a fixed database size continuously, versus paying for capacity consumed with automatic scaling — a crossover decision driven by duty cycle.
REST
An architectural style for APIs built on resources identified by URLs, manipulated with uniform HTTP methods, and stateless requests.
Reactive Streams
A specification for asynchronous stream processing in which the consumer requests a specific number of items, making backpressure part of the protocol rather than an afterthought.
Report Migration Inventory
The enumerated list of every report, extract and downstream consumer of the legacy warehouse, with usage evidence, which is what makes the migration finite.
SQL vs NoSQL
A choice driven by access patterns, consistency requirements and query flexibility — not by data volume, which is the reason usually given.
An order service must notify inventory, billing, shipping and analytics when an order is placed. Synchronous calls or events? Justify your choice per consumer.
What the interviewer is testing Whether you apply the decision per interaction rather than adopting one style globally. The framing that matters Synchronous cal
An order service publishes events consumed by six teams. Every consumer immediately calls back for order details. What is wrong and what do you change?
The failure Thin notification events ("order 123 changed") produce a callback stampede : every event triggers six synchronous calls back to the producer, and th
A design review presents a new event-driven platform. What cost questions do you ask before approving it?
What the interviewer is testing Whether cost is part of your architecture review or an afterthought handled by finance later, and whether you know the specific
Consumer lag on a Kafka topic grows during peak and does not recover overnight. You add consumers and nothing improves. Why?
The mechanism Each partition is assigned to exactly one consumer within a group. With ten partitions and ten consumers, an eleventh consumer joins the group, is
A dashboard has been wrong for three weeks. Nobody knows which upstream produced the table it reads. What is the governance failure, and what fixes it?
The failures, and there are three 1. No lineage. The question "which upstream produced this?" should be answerable in seconds by following a derived dependency
A quarterly board report shows a category down 40%. Investigation finds an upstream system stopped sending a field three months ago. Nothing alerted. What do you change?
Understand why nothing fired The pipeline completed successfully every night. It read the source, applied its transformation, and wrote rows — all of which is w
A service writes to its database and then publishes an event to Kafka. Sometimes consumers see an event for a record that does not exist, and sometimes a record exists with no event. Why, and how do you fix it?
What the interviewer is testing Recognition of the dual write problem — one of the most common defects in event driven systems and one that testing rarely catch
A team proposes exposing their service's database change stream via CDC so other teams can consume it, avoiding the work of building an event API. What is your assessment?
Name what is actually being proposed The proposal is to publish the service's internal schema as its integration contract. CDC does not emit domain events; it e
Orders must trigger inventory reservation, a confirmation email, an analytics record and a fraud check. Queue, topic, or both — and what breaks if you choose wrong?
What the interviewer is testing Whether you know the difference between work distribution and notification — a distinction that produces one of the most confusi
Consumer-Driven Contracts
Consumers declaring what they rely on, and providers verifying against those declarations.
Component Contracts
Props, slots and events as an interface, and the breaking change hidden in a style.
Data Contracts
Producers committing to schema, semantics and freshness, and breaking builds when they do not.
Domain-Driven Design
Ubiquitous language, bounded contexts and context mapping.
Event-Driven Architecture
Publishing facts, and trading comprehensibility for decoupling.
Event-Driven Integration
Publishing facts rather than commands, and versioning event schemas.
API & Integration
General material on integrating systems through contracts.
Chaos Engineering
Hypothesis-driven failure injection with a bounded blast radius.
Event Streaming
Retained ordered logs, consumer offsets, partitions and replay.
Messaging & Queues
Decoupling producer from consumer, and the semantics that come with it.
Partner & B2B Integration
External contracts, onboarding, sandboxes and long deprecation windows.
Platform APIs
Treating the platform's own interfaces as contracts with consumers and compatibility rules.