Neosync vs Mockoon

Free and open source

From $100 per month (Team, billed annually, up to 5 members)

The MIT-licensed code remains free to self-host. The paid cloud service no longer exists — neosync.dev is offline.

Free locally and forever; the paid cloud tier adds hosted mocks and team sync. Team covers 5 members, 3 cloud-deployed mocks and 100k calls a month, with Enterprise on a quote. Work emails get a 14-day trial, others 7 days with a card.

Everything, self-hosted

The desktop app and CLI are free and open source.

Emerging

Nucleus Cloud (acquired by Grow Therapy) · since 2023

Widely used

Mockoon · since 2017

• Open source and self-hostable, so sensitive data never leaves your infrastructure.
• Preserves referential integrity across tables.
• The last release is feature-complete for common Postgres and MySQL anonymisation work.

• Genuinely a minute from download to a working mock API.
• Dynamic templating with faker-style helpers produces realistic responses.
• Proxy mode mocks only the routes you need and passes the rest through.

• Archived and unmaintained since August 2025 — no security patches, no new connectors, no support.
• The hosted cloud has been shut down, so self-hosting is the only option.
• Fewer database connectors than the incumbents.

• Desktop-first; sharing mocks across a team needs the paid cloud or a committed config file.
• HTTP only.
• Less suited to complex stateful behaviour than WireMock.

Realistically, nobody starting fresh. Existing self-hosted users can keep running it, but plan a migration to Tonic or a maintained alternative.

Front-end developers unblocking themselves while a backend is still being built.