JSON Server alternatives: 8 open-source test data and mocking tools
Metrics as of , from the GitHub or GitLab API of each repository. Refreshed monthly.
About JSON Server
JSON Server is a listed test data and mocking tool: npm package that serves a REST API with filtering, sorting and pagination from a JSON file.
Order: Listed tools in the same category, with tools in the same primary language (GitHub API) first, then by GitHub stars. Each line gives one fact from the tool's own documentation where it differs from what JSON Server's documentation states, with its source.
8 alternatives to JSON Server
Nock: Protocols: HTTP, HTTPS. source: README
Sinon.JS: Definition format: Code (JavaScript spies, stubs and mocks). source: README
mountebank: Protocols: HTTP, HTTPS, TCP, SMTP, LDAP, gRPC, WebSockets, GraphQL, SNMP, Telnet, SSH, NETCONF (built in or community extension). source: README
Faker: Definition format: Code (Python generator API via faker.Faker()); command-line faker script. source: README
Mock Service Worker: Protocols: HTTP, GraphQL, WebSocket. source: Docs: Quick start
@faker-js/faker: Definition format: Code (JavaScript API methods; mustache string templates via faker.helpers.fake). source: README
Mockito: Definition format: Code (Java API: mock(), when(), verify(); @Mock, @Spy and @InjectMocks annotations). source: Docs: Mockito site
Bogus: Definition format: Code (fluent Faker<T> API with RuleFor rules, modeled on FluentValidation syntax). source: README
Repository metrics
| JSON Server | 75,7151 | 2026-03-231v1.0.0-beta.15 | 2026-03-231 | MIT | JavaScript | slow |
|---|---|---|---|---|---|---|
| Faker | 19,4051 | 2026-09-141v40.39.0 | 2026-09-151 | MIT | Python | active |
| Mock Service Worker | 18,2161 | 2026-07-081v2.15.0 | 2026-09-081 | MIT | TypeScript | active |
| @faker-js/faker | 15,4931 | 2026-08-141v10.6.0 | 2026-09-221 | MIT | TypeScript | active |
| Mockito | 15,4571 | 2026-03-111v5.23.0 | 2026-09-091 | MIT | Java | active |
| Nock | 13,1261 | 2026-07-301v14.0.17 | 2026-07-301 | MIT | JavaScript | active |
| Sinon.JS | 9,7591 | 2018-01-261v4.2.2 | 2026-07-201 | BSD-3-Clause | JavaScript | active |
| Bogus | 9,7361 | 2025-10-261v35.6.5 | 2025-12-221 | MIT | C# | slow |
| mountebank | 2,1051 | 2026-04-151v2.9.4 | 2026-09-121 | MIT | JavaScript | active |
1 Fetched from the GitHub or GitLab API on . Hover a value for its own date.