Short answer
What to know
Choose JSONPlaceholder for familiar REST resources such as 100 posts and 5000 photos, faked POST, PUT, PATCH and DELETE responses, nested routes and basic filtering by query parameter. Choose Payloads for small immutable files, SHA-256 checksums and the same records in JSON, XML, CSV, YAML, NDJSON, MessagePack, CBOR and PDF.
The short comparison
| Need | Payloads | JSONPlaceholder |
|---|---|---|
| Read JSON without an account or API key | Yes | Yes |
| XML, CSV, YAML and binary formats | Yes | No; JSON API |
| Faked POST, PUT, PATCH and DELETE | No | Yes |
| Nested routes and query filtering | No | Yes |
| Published SHA-256 per file | Yes | Not its main contract |
| Amount of data | 3 users, 2 projects, 3 tasks | 100 posts, 500 comments, 100 albums, 5000 photos, 200 todos, 10 users |
Choose JSONPlaceholder for REST-shaped prototypes
JSONPlaceholder serves six related resources: 100 posts, 500 comments, 100 albums, 5000 photos, 200 todos and 10 users. Its guide says all HTTP methods are supported, and a write returns a faked response because the resource is not really created on the server. It is free with no signup or API key, which makes it a good fit for tutorials and interfaces built around REST calls.
If you want that kind of API on your own machine with your own records, JSON Server serves GET, POST, PUT, PATCH and DELETE routes from a local db.json file. The JSONPlaceholder site names it as its engine.
Choose Payloads for fixture and parser tests
Payloads is less API-like on purpose. Its versioned files fit when the important property is a known response body, an exact media type, the same records across formats or a checksum, rather than server behaviour.