Neosync vs Testcontainers

Free and open source

Free tier available

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

Free. Testcontainers Cloud, which offloads container execution, is a paid Docker product.

Everything, self-hosted

The libraries are free and open source.

Emerging

Nucleus Cloud (acquired by Grow Therapy) · since 2023

Category standard

AtomicJar (Docker) · since 2015

• 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.

• Tests run against the real database engine, so dialect and behaviour differences surface early.
• Containers are disposable, which removes shared-state flakiness entirely.
• Excellent language coverage with idiomatic APIs.

• 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.

• Requires a Docker daemon in CI, which not every environment provides.
• Container startup adds seconds to each test run unless reused carefully.
• Heavier resource usage than in-memory alternatives.

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

Integration tests that currently use in-memory databases and lie to you.