Zero

Zero is a client-server system with an authoritative PostgreSQL backend, not a general offline-first database. It supports local reads and optimistic online mutations but rejects writes after the client enters disconnected or error states.^{13141516171819}

For: TypeScript web teams building highly interactive PostgreSQL applications that are online for writes and fit Zero's current data and deployment boundaries

• The product requires offline writes or prolonged offline operation.
• The client is not a TypeScript web application or the authoritative backend is not compatible PostgreSQL.
• The synchronized dataset, query model, permissions, schema, or current recommended scale does not fit.
• The team cannot operate self-hosted topology and managed Cloud onboarding is unavailable or unacceptable.
• Mutation rejection, rollback, authorization, logical replication, backup, and recovery behavior fail production testing.

• Query-driven synchronizationClient queries determine the data synchronized into Zero's normalized local datastore.^13151618
• Optimistic online mutationsMutators run locally first, then execute through an application-owned server endpoint and reconcile from PostgreSQL.^13151618
• GA open-source coreRocicorp marks Zero generally available and fully supported, with Apache-2.0 client and server code.¹⁴
• Self-hosted routeDocumented deployment includes zero-cache components, PostgreSQL, application query and mutate endpoints, local replica storage, and backups.^13151618

Zero's Apache-2.0 open-source core has no separate software license fee when self-hosted; infrastructure, PostgreSQL, storage, compute, backup, observability, and operations remain the team's cost. Managed Cloud publishes fixed Hobby and Professional prices plus storage or compute additions and a BYOC price, but access is currently described as onboarding rather than full public availability.¹⁴²⁰

Self-hosted core

Apache-2.0 client and server with infrastructure and operations owned by the team¹⁴²⁰

Managed plans

Published Hobby, Professional, and Bring Your Own Cloud prices and resource allowances¹⁴²⁰

Availability boundary

Core product GA; managed Cloud is onboarding and full public availability remains a roadmap item¹⁴²⁰