Setting up multi-user

Multi-user access lets multiple people work in the same .solid file from their own computers, without sync conflicts or shared-drive surprises. Setup takes 10–15 minutes for a small team. This guide walks through both modes.

For the conceptual model (why Solid does it this way), see the Multi-User module.

Prerequisites

Solid Accounting Pro or Accountant tier — Standard tier is single-user only
All users on the same LAN — wired or wifi to the same network. For remote users, set up a VPN first (see Beyond the LAN below)
A machine that hosts — see the next section to pick

Pick your authority — Host Mode or Dedicated Server

The first decision: which machine holds the canonical .solid file?

	Host Mode	Dedicated Server
What it is	A regular Solid Accounting install with hosting enabled	A headless server build (no GUI)
Runs on	Someone's laptop or workstation	A NAS, an always-on workstation, a small VM
Best for	2–5 users, occasional concurrent	More users, time zones, always-on access
Cost	Same as a regular install	Same license; just runs server build
Limitation	Goes offline when the host machine sleeps or shuts down	Requires a machine that's always on

For a small office team where everyone shares an open-plan workspace and the bookkeeper's laptop is always running during business hours: Host Mode. For a company with remote workers, after-hours bookkeeping, or more than ~5 active users: Dedicated Server.

You can start with Host Mode and migrate to a Dedicated Server later — the file moves; the protocol and the client experience don't change.

Path A — Host Mode setup

Step 1 — Open the file on the host machine

The host is whichever machine holds the .solid file going forward. Typically the file owner's machine (the bookkeeper, the business owner, etc.).

Open Solid Accounting on the host machine and open the file you want to share. Authenticate as the file Admin.

Step 2 — Enable Host Mode

Settings → Multi-User → Enable Host Mode

Solid:

Starts the embedded API server on the host machine (default port 21384, configurable)
Begins the mDNS broadcast (_solidaccounting._tcp.local) so clients on the LAN auto-discover the host
Shows a Hosting · 0 connected indicator in the title bar

The host machine now serves the .solid file's authority. From this moment, any other Solid client on the same network can discover and connect.

Step 3 — Add users

Each user who'll connect needs a user record on the file:

File → Manage Users → New
Enter their name and email (used for the invite)
Pick their role — Admin, Bookkeeper, or Read Only (see Multi-User → Roles)
Solid generates a one-time invite code and shows it once

Send the invite code to the user (text, email, or just say it across the office). They'll enter it on first connect.

Step 4 — Each user connects from their machine

On each client machine:

Install Solid Accounting (same installer as the host; client mode auto-detects)
Activate their license seat (each user uses one of the file's tier-allowed seats; no separate license per client needed)
Solid's welcome screen lists discovered hosts on the LAN — pick yours
Enter the invite code you provided
Set a personal password — used for subsequent logins to this file
Connected — the file opens just like a single-user file, but every read/write goes through the host

After the first connect, the client remembers the host and the user's session. Subsequent opens are one-click.

Step 5 — Verify

Have someone post a transaction on a client. Watch it appear instantly on the host (and on any other connected clients). If it does, multi-user is working.

If transactions don't appear, jump to Troubleshooting below.

Path B — Dedicated Server setup

Step 1 — Pick a server machine

Common choices:

Machine type	Considerations
NAS (Synology, QNAP, etc.)	Always on, low power, often has Docker support. Solid offers a Docker image.
Small VM (cloud or office)	Easy to provision, easy to back up. ~1 GB RAM is enough for small files.
Office workstation kept always-on	Cheapest if you have one. Tape over the power button.
Mini PC (Intel NUC, similar)	Dedicated hardware, low power, often under $300.

The server machine needs:

64-bit OS (Linux, macOS, or Windows)
1 GB+ RAM
500 MB disk + however much your .solid file is (typically under 1 GB)
A stable network connection (wired preferred)

Step 2 — Install the server build

Three options:

Native install — download the headless server build from solidaccounting.com/download and run it as a daemon (systemd unit on Linux, launchd on macOS, Service on Windows)
Docker — docker pull solidaccounting/server:latest and configure with environment variables
Bundled with desktop — every regular install includes the server build; run it directly via solid-server --file /path/to/file.solid

For Linux servers and NAS, the Docker route is usually cleanest. For Mac and Windows servers, native install is simpler.

Step 3 — Place the .solid file

Copy your .solid file to a permanent location on the server. Common paths:

Linux: /var/lib/solidaccounting/yourcompany.solid
macOS: /Library/Application Support/SolidAccounting/yourcompany.solid
Windows: C:\ProgramData\SolidAccounting\yourcompany.solid
Docker volume: mounted at /data/yourcompany.solid inside the container

Step 4 — Start the server

Start the server pointing at the file. The server:

Authenticates against your license server (one-time, uses the same activation key as desktop)
Starts the API server on the configured port
Begins mDNS broadcast on the LAN

You'll see startup logs confirming the file opened, the server is listening, and mDNS is broadcasting.

Step 5 — Add users (same as Host Mode)

User management happens via any connected client (or via the API). The Admin can:

Create users
Assign roles
Generate invite codes

The exact same flow as Host Mode — the server is just running headlessly instead of in a GUI.

Step 6 — Each user connects

Same as Host Mode — clients auto-discover the server on the LAN, enter their invite code, connect.

Beyond the LAN — remote users

mDNS auto-discovery only works on the same physical network. For users in different offices or working from home:

Option 1 — VPN

The simplest. Use whatever VPN you already have for file shares and printers (Tailscale, WireGuard, OpenVPN, IPSec). When a remote client connects to the VPN, they appear to be on the office LAN; mDNS discovery works.

Tailscale is particularly clean because:

Each device gets a stable hostname (server.tail-acme.ts.net)
Solid clients can connect via that hostname directly, skipping mDNS
No port forwarding, no public exposure

Option 2 — Manual address entry

If you have a stable hostname or IP for the server (a Cloudflare tunnel, a static office IP with port forward), clients can connect manually:

Welcome screen → Connect to a Solid Accounting server → manual entry
Hostname or IP + port (e.g. solid.acme.com:21384 or 203.0.113.42:21384)
Solid validates the hostname against the file and prompts for the user's invite code

Option 3 — Hosted multi-user (future)

Solid's roadmap includes a managed coordination service for multi-user files, where the server runs in our infrastructure. Not currently offered — for now, VPN is the answer.

Backup considerations

Cloud Backup runs on the authority machine (the host or server). Configure it once on the authority; clients don't run their own backup (they don't hold the file).

If you migrate from Host Mode to Dedicated Server, configure Cloud Backup on the server with the same destination, password, and recovery phrase. The catalog continues across the move.

For physical-copy backups (NAS dump to external drive), the file is just a file; copy it like any other. Stop the server briefly during the copy if you want a guaranteed-consistent snapshot, or use a filesystem snapshot if available.

Performance

Multi-user in Solid is designed to feel like single-user. Expect:

Read latency: under 50ms for typical operations on a LAN
Write latency: under 100ms (writes go through the authority's validation layer)
Sync latency: under 500ms from one client posting to other clients seeing the change

If latency feels worse than this, troubleshoot:

Check the LAN — gigabit wired beats wifi by a lot for write-heavy workloads
Check the host/server CPU — if the host is also running other heavy workloads, contention shows up as latency
Check the file size — files over ~500 MB feel slower; consider archiving old data into a separate file

Troubleshooting

Client can't see the host on the welcome screen. mDNS isn't traversing. Check:

Both machines on the same network/subnet (not on guest wifi vs main LAN)
Firewall on the host allows incoming connections on port 21384
mDNS isn't blocked at the network level (some corporate networks restrict multicast)

Connected but transactions don't sync. The client's session may be stuck. Disconnect and reconnect. If it persists, check the host's Sessions dialog — your session shows up; revoke it and reconnect fresh.

"Authority unavailable" — the host or server stopped responding. On the host, check that Solid is still running and Host Mode is still enabled. On a server, check the systemd/launchd/service status.

Two users editing the same record at the same time — Solid's authority model serializes writes; one of them will win, the other will see "record was modified, refresh to see latest." Don't worry about explicit locking — the protocol handles it.

Slow performance on a particular client only — that client's network or machine, not the host. Try the same machine on a wired connection or restart it.

Cross-references

Multi-User module — the conceptual model
Migrating between machines — moving the host/server
Cloud Backup module — backup runs on the authority
REST API — programmatic access works against multi-user files the same way