Integration Landscape
The inventory of connections between systems, which is usually larger, less documented and more expensive than the application inventory itself.
Organisations inventory applications and rarely inventory integrations, which is why the integration estate is where most unmanaged complexity lives. A hundred applications can carry several hundred point-to-point connections, each built by a different team at a different time with different assumptions.
The costs that accumulate invisibly: every integration is a coupling that must be maintained through both systems' changes; failure modes multiply, since a chain of synchronous integrations propagates outages; and impact analysis becomes impossible, so nothing is ever safely changed or retired.
What to record: the systems at each end, the direction and mechanism (API, file, message, direct database access), the frequency and volume, the data crossing with its classification, the owner, and the criticality.
The patterns that reduce the count rather than merely documenting it: an event backbone, where publishing once serves many consumers instead of building a connection per pair; API-led access with a gateway, replacing direct database integration; and retiring shadow integrations — the direct database reads and scheduled scripts that nobody owns and everybody depends on.
The finding that recurs: the most business-critical integration in the estate is frequently a scheduled file transfer written years ago by someone who has left.