API Path

Overview

Meaning and scope

API Path is the portion of an API URL that identifies a resource or operation relative to the base URL. It is used to route a request to the intended capability and encode hierarchical resource relationships. It differs from a query parameter, which modifies or filters a request without selecting the primary route.

Mechanism and operation

The client joins the documented path with the base URL, substitutes encoded path parameters, selects an HTTP method, and sends the request. The API Path owner should publish stable error semantics and guidance on whether correction, retry, status lookup, or escalation is appropriate. Important failure modes include incorrect encoding, ambiguous trailing slashes, path traversal, conflicting routes, and placing sensitive values in paths. Observability for API Path should record operation, version, principal, request ID, latency, retry count, error code, and final state without exposing secrets. Operational evidence should include base URL, path template, concrete path, method, route name, parameter values, and API version.

Practical payment example

An SDK sends a payout request to a versioned resource path. When migrating API versions, engineers verify the path and response schema together so a syntactically valid request cannot silently invoke the wrong operation.

Operational checks

API Path should be documented alongside API Base URL, API Gateway, and API Version. For API Path, the application should preserve a correlation path from request construction through response, asynchronous completion, and final business state. Testing API Path should cover malformed input, denied access, rate limits, timeouts, duplicates, asynchronous completion, and version changes.

Distinctions and limits

Common risks include incorrect encoding and ambiguous trailing slashes. Define consistent naming, validate and encode parameters, avoid secrets, document case rules, version deliberately, and test routing conflicts.

Related reading

Related definitions: API Base URL, API Gateway.