How do I move off Real-Time Sync Frameworks without getting stuck?
New real-time sync platforms (Convex, Electric SQL) compete with Supabase Realtime on pricing, consistency guarantees, and offline-first support. Teams need to evaluate transactional reactivity, local-first architecture, vendor lock-in, and per-seat vs. usage-based cost models.
Blockers
- requires_version: engine/electric-sql → package/postgres
- Lock-in via vendor/supabase
- Lock-in via vendor/convex
Who this is for
- real-time
- serverless
- cost-sensitive
- small-team
- low-ops
- high-scale
Candidates
Convex
As of 2026-03-16, Convex is a reactive backend-as-a-service with a custom transactional document store. Free plan includes 1M function calls/month and 0.5 GB storage; Professional is $25/developer/month with 25M function calls and 50 GB storage. Every query is a live subscription: Convex tracks all data dependencies per query function and automatically reruns it—pushing updates to all active clients—whenever any dependency changes.
When to choose
Best for small-team + low-ops or real-time + serverless stacks where strong consistency across reads and writes is non-negotiable and you want reactivity by default rather than as an add-on. The decisive factor is Convex's transactional read-write model: unlike WAL-based approaches, subscriptions and mutations share the same channel, eliminating the read-after-write consistency gap common in Supabase Realtime.
Tradeoffs
Strongest consistency story of the three: query subscriptions and mutations run inside the same transactional document store, making read-after-write consistency automatic. TypeScript-native schema inference means no SQL or migration files. Includes vector search, file storage, crons, webhooks, auth, and scheduled functions without extra vendors. Tradeoff is no SQL and no offline/local-first support—Convex is fully cloud-dependent; if the subscription drops, clients have no local copy. Actions (for external API calls) explicitly do not carry the same transactional guarantees as queries and mutations.
Cautions
Convex uses a custom document store, not Postgres—teams that need SQL joins, existing Postgres tooling, or portable schemas will hit a hard architectural wall mid-project. There is no offline mode; all reactivity requires an active connection, making it unsuitable for local-first or intermittently-connected use cases. The $25/developer/month Professional pricing compounds quickly on larger teams—verify current per-seat costs at convex.dev/pricing before committing.
Electric SQL
As of 2026-03-16, Electric SQL is an open-source (Apache 2.0) read-path sync engine for Postgres, version 1.0 stable. It consumes Postgres logical replication and distributes data via HTTP-based 'Shapes' (partial replicas with WHERE-clause filtering) to clients, CDNs, TanStack DB, or PGlite. Electric Cloud is in public BETA with a stated free tier; no public pricing tiers are listed—contact the team for details on usage beyond the free tier. Self-hosting requires Postgres v14+ with logical replication enabled and a Docker-containerised Elixir service.
When to choose
Best for real-time + low-ops or local-first + cost-sensitive teams that already run Postgres and want offline-capable or edge-cached sync without replatforming to a new database. The decisive factor is Electric's read-path architecture: it syncs data out of any existing Postgres instance, making it an additive layer rather than a database replacement, and it integrates with standard CDNs for fan-out at scale.
Tradeoffs
Works with any Postgres (Supabase, Neon, RDS, self-managed)—no database migration required. Apache 2.0 license means full self-hosting with no vendor lock-in. HTTP+CDN delivery scales fan-out without per-connection infrastructure. TanStack DB and PGlite enable true offline-first clients. Tradeoff is that Electric is a read-path-only engine: it does not handle write-path sync, conflict resolution, or mutations—teams must wire up their own write path (REST, tRPC, or direct Postgres). Cloud BETA pricing is not publicly listed, and the Elixir self-host adds operational complexity.
Cautions
Electric is read-path only—it cannot write back to Postgres on behalf of clients; you must implement your own write/conflict strategy, which eliminates it as a drop-in Firebase replacement for bidirectional sync. The Electric Cloud is in public BETA as of 2026-03-16 with no published paid pricing tiers; assume pricing will change before GA and verify current status at electric-sql.com before building production cost models around the managed service. Self-hosted deployments need NVMe-class disk for the Elixir sync service to maintain low-latency WAL streaming.
Supabase Realtime
As of 2026-03-16, Supabase Realtime is a globally distributed WebSocket layer bundled with the Supabase platform, offering three capabilities: Broadcast (low-latency pub/sub between clients), Presence (shared user-state tracking), and Postgres Changes (streaming WAL-based database change events). Free plan includes 2M messages/month and 200 peak connections; Pro and Team plans include 5M messages/month and 500 peak connections, with usage-based overage charges beyond those quotas. Enterprise pricing is custom.
When to choose
Best for teams already using Supabase (Postgres, Auth, Storage) where adding real-time event notifications and presence avoids a separate vendor. The decisive factor is platform consolidation: Supabase Realtime is not a reactive query system but a Postgres change-event bus, which is the right fit for notification-style use cases (activity feeds, live dashboards) but not for full transactional reactivity where read-after-write consistency is required.
Tradeoffs
Tightly integrated with Supabase's Postgres, auth, and storage stack—no separate vendor contract for real-time. Broadcast and Presence are low-latency and don't touch the database. Row-Level Security policies apply to Postgres Changes, giving declarative access control over which change events clients can receive. Tradeoff is that Postgres Changes watches the WAL, not the query result—subscriptions are delivered on a different channel than writes, which means Supabase cannot guarantee the same read-after-write consistency as Convex. No offline/local-first support; Supabase Realtime is purely event-notification.
Cautions
Postgres Changes delivers WAL events, not re-evaluated query results—if a client needs the current computed state (not just the raw row delta), it must re-query Postgres after receiving a change event, creating a second round-trip. This architecture also means complex filtered queries cannot be subscribed to with guaranteed consistency in the way Convex query subscriptions work. Supabase Realtime overage pricing (per million messages and per thousand peak connections) is not confirmed on the docs page fetched—verify current exact overage rates at supabase.com/docs/guides/realtime/pricing and supabase.com/pricing before sizing Pro vs. Team plans.
Try with your AI agent
$ npm install -g pocketlantern $ pocketlantern init # Restart Claude Code, Cursor, or your MCP client, then ask: # "How do I move off Real-Time Sync Frameworks without getting stuck?"