Short answer

What to know

Choose DummyJSON for richer application data, pagination, search, authentication examples and REST-style interactions. Choose Payloads for small stable inputs, non-JSON formats, binary decoder tests and byte-level verification.

The short comparison

NeedPayloadsDummyJSON
Small deterministic fixturesCore purposeAvailable data, broader API focus
Rich product and recipe dataNoYes
Search, pagination and auth examplesNoYes
XML, CSV, NDJSON, MessagePack and CBORYesNo; JSON API
PDF download fixtureYesNot its main purpose
Manifest with SHA-256YesNot its main contract

Choose DummyJSON for application-like data

DummyJSON publishes multiple realistic datasets and documents features such as pagination, search, authentication and HTTP response helpers. That is a stronger fit for a frontend that needs to behave as though it is talking to an application backend.

Choose Payloads for controlled input

Payloads trades breadth for a smaller test surface. It is easier to inspect every record, compare representations and pin exact bytes when you are testing parsers, importers, clients or file flows.

Primary reference