Documentation / Platform glossary / API
An application programming interface is a defined contract through which one system uses another's capabilities. The contract is the substance: it states what operations exist, what they accept and return, and how failures are reported, so callers can depend on behaviour rather than on implementation.
For web APIs the contract has several parts. Resources and operations define what can be acted on. Request and response shapes define the data exchanged. Authentication and authorization determine who may call and what they may do. Error semantics define how failures are communicated. Versioning defines how the contract may change without breaking existing callers.
Two of these are consistently underestimated.
Error semantics. An API that returns errors in a structured, documented form — a stable machine-readable code plus a human-readable message — lets callers handle failures programmatically. One that returns prose in varying shapes forces integrators to match on message text, which then breaks when the wording is improved.
Versioning. A published contract cannot change incompatibly without breaking callers, so additive change and explicit versions are what allow a platform to evolve. Removing a field or changing a type is a breaking change even when it looks like a cleanup.
The value of the contract is that it is a boundary. Callers depend on the stated interface, not on internal structure, which is what lets the implementation change freely — and what makes an undocumented but relied-upon behaviour a liability.
APIs are how a platform participates in an organization's existing systems rather than becoming another silo. The quality of the contract determines the long-run cost of that integration far more than the initial implementation effort.
For an evaluator the useful questions are whether versioning is explicit, whether errors are structured, and whether programmatic access carries the same identity and tenant context as interactive access.
QueryTek exposes versioned API surfaces with consistent request, response, and error shapes. Programmatic access resolves to a tenant and is attributable to a caller. Endpoint catalogues and authentication detail are delivered through authenticated channels, not public documentation.
