# rocicorp/mono

99% of Queries in Zero Milliseconds

Repository: https://github.com/rocicorp/mono
Canonical: https://ross.abutalabs.com/products/rocicorp-mono
Homepage: https://zero.rocicorp.dev/
Language: TypeScript
License: Apache-2.0
License Family: permissive
Last push: 2026-08-26T22:05:43+00:00

## Health v2 (maintenance only)
Score: 66/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 8, longevity 92
- inputs: {"age_days": 1301, "days_push": 7, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3369, forks 159 (observed 2026-08-28T04:07:58.357012+00:00)

## What it is
Zero is a general-purpose sync engine for the web that syncs slices of a Postgres database into a client-side local datastore, letting queries resolve instantly from cache while syncing in the background. The monorepo also contains Replicache, the underlying client-side sync library, and ZQL, a TypeScript query language with incremental view maintenance.

## Use cases
- build web apps with instant, local-first reads and writes
- sync only the data a user has permission to see from Postgres
- query client-side cached data with a SQL-like TypeScript API
- avoid writing HTTP APIs and state management for data fetching
- make large datasets (millions of rows) feel fast in the browser
- keep UI reactively updated as server data changes

## When to choose
- you want Linear/Figma-style instant UX backed by Postgres
- your app has complex permissions and too much data to sync wholesale
- you use React, SolidJS, or React Native and want reactive queries
- you want an open-source, self-hostable sync layer

## When to avoid
- your backend is not Postgres
- you need heavy server-side aggregation or column-subset queries
- you want a fully managed proprietary solution with vendor SLAs
- your data is write-heavy with strict server-side transactional requirements

## Facets
- artifact type: library
- maturity: active
- function: caching, database, orm, state-management, middleware
- domain: web-development, frontend, databases, developer-tools
- platform: browser, cross-platform
- tags: sync-engine, client-side-datastore, incremental-view-maintenance, postgres-replication, local-first, zql, reactive-queries, real-time, typescript, nodejs, web-server

## Member repositories
- rocicorp/mono (main) score 66

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:58.357012+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:39:58.108816+00:00, confidence not recorded.
  - readme: https://github.com/rocicorp/mono (fetched 2026-08-28T04:07:58.357012+00:00, sha 1342cab52ca4)
  - homepage: https://zero.rocicorp.dev/ (fetched 2026-08-29T09:33:48.397186+00:00, sha 62d0076bd0ec)
  - site_page: https://zero.rocicorp.dev/docs/zql (fetched 2026-08-29T09:33:48.406212+00:00, sha 4a1e4cd26aaa)
  - site_page: https://zero.rocicorp.dev/docs/open-source (fetched 2026-08-29T09:33:48.408367+00:00, sha b76a41161dc4)
  - site_page: https://zero.rocicorp.dev/docs/introduction (fetched 2026-08-29T09:33:48.409999+00:00, sha 459171da21cf)
- Data as of 2026-08-30T08:39:29.467469+00:00.