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Legacy Integration

Reaching systems that cannot change, without importing their model.

4Questions
11Flashcards
3Terms
Drill this topic All of API & Integration Architecture
Questions

4 to work through

  1. intermediate Multiple choice

    A modern service must read from a legacy system that offers only nightly batch files and a synchronous interface that cannot handle concurrent load. What integration approach fits?

    2 min answer
  2. advanced

    A core mainframe system with no API supports nightly batch file exchange only. The business needs near-real-time order status. Design the integration.

    2 min answer
  3. advanced

    An insurance platform must integrate with a legacy policy administration system with a rigid data model and batch-only interfaces. How should the boundary be designed?

    2 min answer
  4. advanced

    The system of record updates nightly and cannot be changed. Product teams need to build against it. Design the integration.

    2 min answer
Terminology

3 terms in this topic

pattern

File-Based Integration

Exchanging data as files on a schedule via SFTP or shared storage — dated, still ubiquitous, and workable when its failure modes are handled explicitly.

 practice

Legacy Integration

Connecting modern services to systems that cannot be changed — where the constraints are as much commercial and operational as technical.

 concept

Shared Database Integration

Two or more applications reading and writing the same database directly — the most damaging integration pattern and the hardest to unwind.
API & Integration Architecture

Neighbouring topics

API & Integration

General material on integrating systems through contracts.

4 quiz 15 cards 13 terms

REST Design

Resources, uniform methods, status codes and statelessness.

4 quiz 7 cards 3 terms

GraphQL

Client-specified queries, N+1 resolution and query-cost control.

4 quiz 9 cards 4 terms

gRPC APIs

Contract-first RPC, generated clients and protobuf compatibility rules.

3 quiz 8 cards 3 terms

Webhooks

Push callbacks, signature verification, ordering and at-least-once delivery.

5 quiz 12 cards 7 terms

API Versioning

URL, header and account-pinned versioning, and who carries the burden.

5 quiz 9 cards 5 terms

Backward Compatibility

Which changes are safe, and how to make breakage a build failure.

3 quiz 6 cards 3 terms

Contract Testing

Verifying what consumers actually rely on, without a shared environment.

5 quiz 12 cards 2 terms

API Documentation

OpenAPI as a machine-checked contract rather than as prose.

4 quiz 5 cards 2 terms

Rate Limiting

Algorithms, shared counters, and signalling rejection properly.

4 quiz 12 cards 4 terms

Idempotency Keys

Client-generated keys stored atomically with the operation they guard.

5 quiz 7 cards 3 terms

Pagination & Filtering

Offset versus cursor, stable ordering and unbounded result sets.

4 quiz 7 cards 3 terms

API Error Handling

Error shapes, retryability signals and machine-readable causes.

3 quiz 11 cards 4 terms

Event-Driven Integration

Publishing facts rather than commands, and versioning event schemas.

4 quiz 11 cards 5 terms

Message Formats

JSON, Protobuf, Avro — schema evolution and payload economics.

3 quiz 8 cards 2 terms

Schema Registry

Enforcing compatibility on events the way CI enforces it on code.

2 quiz 7 cards 4 terms

Integration Patterns

Routers, translators, splitters, aggregators and dead letter channels.

3 quiz 8 cards 6 terms

Partner & B2B Integration

External contracts, onboarding, sandboxes and long deprecation windows.

4 quiz 9 cards 3 terms

APIs as Products

Ownership, lifecycle, deprecation policy and developer experience.

5 quiz 12 cards 3 terms