---
title: Zero
slug: rocicorp-zero
url: "https://toolweight.com/options/rocicorp-zero"
homepage: "https://zero.rocicorp.dev"
categories: convex-alternatives
last_verified: 2026-07-20
license: CC-BY-4.0
---

# Zero

> Sync engine that puts a queryable client cache in front of your own Postgres.

Zero is Rocicorp's general-purpose sync engine, the successor to Replicache. Your Postgres stays the source of truth; zero-cache replicates from it and serves ZQL queries to clients out of a local store, so reads are instant and writes go through custom mutators that run server-side in a real transaction. It brings no auth, storage or cron, it does one thing and leaves the rest of your stack alone.

## Identity

|  |  |
| --- | --- |
| Name | Zero |
| Company | Rocicorp |
| One-liner | Sync engine that puts a queryable client cache in front of your own Postgres. |
| Site | https://zero.rocicorp.dev |
| Docs | https://zero.rocicorp.dev/docs |
| Repo | https://github.com/rocicorp/mono |
| Founded | 2019 |
| Funding | Venture-backed |
| Open source | Yes |
| Compared in | 1 |

## Where it is compared

### [Convex alternatives](https://toolweight.com/compare/convex-alternatives)
Ranked **#3 of 11** on default weights.
| Field | Value | Confidence | Verified | Source | Note |
| --- | --- | --- | --- | --- | --- |
| Reactivity | push | Vendor-claimed | 2026-07-20 | https://zero.rocicorp.dev/docs | ZQL queries resolve from a client-side cache and update as zero-cache replicates changes out of Postgres. |
| TS inference | ● | Vendor-claimed | 2026-07-20 | https://zero.rocicorp.dev/docs/zero-schema | Schema defined in TypeScript, inferred through ZQL results. |
| Transactions | mvcc | Inferred | - | - | Custom mutators run server-side inside a real Postgres transaction; the client applies a speculative version first. |
| Local-first sync | ● | Vendor-claimed | 2026-07-20 | https://zero.rocicorp.dev/docs | - |
| Optimistic writes | ● | Vendor-claimed | 2026-07-20 | https://zero.rocicorp.dev/docs | Speculative mutations with server rebase, the core of the design, not an add-on. |
| Cron & scheduling | ○ | Inferred | - | - | Not a backend; bring your own. |
| File storage | ○ | Inferred | - | - | - |
| Vector search | ◐ | Inferred | - | - | Whatever your own Postgres has; Zero does not sync it. |
| Full-text search | ◐ | Inferred | - | - | Available in your Postgres, outside the sync path. |
| Auth | bring-your-own | Vendor-claimed | 2026-07-20 | https://zero.rocicorp.dev/docs/auth | Verifies your JWT; permissions are declared against its claims. |
| Hard limits | Client cache size is the practical ceiling, the query set you sync has to fit on the device. | Inferred | - | - | - |
| Cold start | - | Unknown | - | - | zero-cache is a long-running process you operate. |
| Function timeout | - | Unknown | - | - | Mutators run on your own server. |
| Exit cost | 3 | Inferred | - | - | Your Postgres is never given up: schema, data and writes stay in SQL you own. Leaving means deleting the sync layer and rewriting the read path from ZQL back to queries, real work, but it never touches your data model. |
| Self-hostable | ● | Vendor-claimed | 2026-07-20 | https://zero.rocicorp.dev/docs/deployment | Self-hosting zero-cache is the primary deployment model. |
| Bulk export | ● | Inferred | - | - | It is your Postgres. |
| Raw SQL | ● | Inferred | - | - | Directly against your own database, though writes should go through mutators to stay consistent with connected clients. |
| Schema changes | sql-migrations | Inferred | - | - | Your own Postgres migrations, plus a Zero schema that has to be kept in step. |
| MCP server | ○ | Inferred | - | - | - |
| Agent fit | 3 | Inferred | - | - | Typed and in-repo, but the operational surface, replication, cache deployment, is not something an agent finishes alone. |
| Pricing model | free (self-host) | Inferred | - | - | You pay for the machines running zero-cache and Postgres. |
| Entry price | $0 /mo | Inferred | - | - | No hosted product priced at time of writing; costs are infrastructure. |
| Egress metered | ○ | Inferred | - | - | Your infrastructure, your bandwidth bill. |
| GitHub stars | 3,000 | Inferred | - | - | rocicorp/mono, approximate as of mid-2026. |
| Backing | venture-backed | Inferred | - | - | - |
| Positioning | A general-purpose sync engine for the web. | Vendor-claimed | 2026-07-20 | https://zero.rocicorp.dev | - |

**Verdict.** The most interesting shape on this page: instant local reads without surrendering the database. You still operate zero-cache and Postgres yourself, and you get no auth, storage or cron, this is a layer, not a platform.

## Alternatives

- [Appwrite](https://toolweight.com/options/appwrite), Open-source backend platform: databases, auth, storage, functions, self-hostable.
- [Convex](https://toolweight.com/options/convex), Reactive TypeScript backend: database, functions and live queries in one project.
- [ElectricSQL](https://toolweight.com/options/electricsql), Postgres read-path sync: stream subsets of your own database to clients over HTTP.
- [Firebase](https://toolweight.com/options/firebase), Google's app platform: Firestore documents, auth, functions, deep mobile SDKs.
- [InstantDB](https://toolweight.com/options/instantdb), Client-side reactive database with a relational graph model and instant sync.
- [Neon + Drizzle](https://toolweight.com/options/neon-drizzle), The DIY baseline: serverless Postgres, a typed SQL query builder, nothing else.
- [Nhost](https://toolweight.com/options/nhost), Postgres plus Hasura GraphQL, auth, storage and serverless functions.
- [PocketBase](https://toolweight.com/options/pocketbase), One Go binary: SQLite database, auth, file storage, realtime and an admin UI.
- [Supabase](https://toolweight.com/options/supabase), Managed Postgres with auth, storage, realtime and edge functions around it.
- [Triplit](https://toolweight.com/options/triplit), Full-stack database that syncs: local cache, server, relational queries, offline.

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