Sync Server Docs

Run sync on your own terms.

Simply Finance already includes built-in sync servers, so most people never need to touch this. This page is for advanced users who want to self-host their sync infrastructure or choose their own sync servers.

  • ✓Local-first by default
  • ✓End-to-end encrypted sync
  • ✓Bring your own sync server when needed
What sync servers seeEncrypted blobs only

Sync servers move data between devices, but they do not get readable transaction data.

Best fitAdvanced owners

Useful when you care about infrastructure control, geography, compliance, or redundancy.

Want the protocol-level details?

Simply Finance syncs over SimplySync, our local-first sync engine. The SimplySync developer guide has the deployment and server-side references.

What a sync server does

A sync server is the network service that helps your devices exchange encrypted changes. Think of it as a mailbox for sync updates, not as a database operator reading your finances.

Simply Finance stays local-first. Your device keeps the working copy of the database. The sync server only helps devices discover and exchange encrypted updates so the same owner can restore and sync across your iPhone and Android devices.

  • Your data is encrypted before it leaves the device.
  • Sync servers cannot read balances, transactions, budgets, or notes.
  • Adding a custom sync server changes the transport path, not the ownership model.

Who should use this

Most users should keep the built-in setup. It is the easiest path and it keeps restore working out of the box.

Bring your own sync server when you want tighter infrastructure control: self-hosting, a provider you trust, a regional endpoint, or a second sync server for resilience.

Good rule of thumb

If you do not already know why you want a custom sync server, you probably do not need one yet.

How it works in Simply Finance

Open Settings > Sync Servers to inspect current sync servers, check their status, or add a new one. When you add a compatible sync server URL, Simply Finance starts using it for the same encrypted owner data.

  • Built-in sync servers remain enabled so restore is not blocked by manual setup.
  • You can verify a sync server is healthy from the Connected status badge.
  • You can remove added sync servers later without affecting local data already on the device.
Important

Custom sync servers are an advanced feature. They are best for people who want to self-host their sync infrastructure and are comfortable managing servers.

Requirements

Simply Finance syncs over SimplySync, so your sync server endpoint needs to speak the SimplySync sync protocol. Public endpoints should use secure WebSockets.

wss://sync.example.com
  • Use wss:// for internet-facing sync servers.
  • Use ws:// only for local development or trusted internal networks.
  • See the SimplySync developer guide if you need deployment details.

Setup checklist

This is the shortest safe path for trying a custom sync server without breaking your current sync setup.

Self-hosting on Cloudflare?

The Cloudflare quick guide walks through deploying your own encrypted relay on Workers, D1, and R2 in about fifteen minutes — including the rate-limit rule that keeps the bill safe.

1

Deploy or choose a compatible sync server

Use the SimplySync guide if you are hosting your own, or get a stable WebSocket endpoint from your provider.

2

Add it in Sync Servers

Paste the sync server URL into Simply Finance. Keep the built-in sync servers enabled unless you have a specific migration plan.

3

Confirm the connection badge

Wait for the status to switch to Connected. If it fails, double-check the URL, TLS, and server logs.

4

Test restore on another device

Before you rely on the new sync server, verify another device can restore and sync the same encrypted owner data.

FAQ

Can the sync server read my financial data?

No. The sync server can transport encrypted sync data, but it does not have the keys needed to read your transactions.

Do I need a custom sync server to use sync?

No. Built-in sync servers are the default and are the right choice for most people.

What happens if my custom sync server goes down?

Your local database stays intact. Sync pauses until a healthy sync server is available again.

Where do I learn the server-side details?

Simply Finance syncs over SimplySync, our local-first sync engine. The SimplySync developer guide is the right source for hosting, protocol expectations, and deeper implementation notes.