The short version
Three commands, then one address. You need Docker, Git and a terminal. macOS and Linux are the tested paths. Nobody has run Postern on Windows — Install Postern carries the untested Windows lines. Keep.env. Postgres records that password on the first start, and it never accepts a
different one against the same data.
docker compose down -v destroys, and the Console from another computer. It also
does the same install without Git.
Start here
Install Postern
Docker and a terminal · about 10 minutes · no cloud account
Set up remote access
Tailscale, and Funnel only if a hosted agent needs a public address · about 20
minutes, once · off by default
Mint your first key
a name, the sectors it opens, a deadline · a few minutes · Postern shows the key once
Connect an agent
a key you created · a few minutes, plus a restart of the agent · claude.ai and
ChatGPT need a public address first
Connect a source
Eight sources, each with its own page. Connect as many or as few as you want. A sector answers with whatever you connected in it. A new source never changes a grant you already made.- Finance — SimpleFIN, the one to start with; Plaid for banks SimpleFIN cannot reach
- Mail, calendar and contacts — Google and Gmail, Microsoft, iCloud
- Health — Apple Health, which your iPhone sends; WHOOP
- Home — Home Assistant, the only source an agent can act on
Understand how it works
- Security model — the premise the rest of this list follows from, and what has not been reviewed
- Which computers can reach Postern — the two ports, and why the Console has no password
- The vault and the master key — what Postern encrypts, what it does not, and the one command that destroys the key
- Provider sign-ins — the redirect address, what each provider needs, and the credentials that behave like passwords
- Grants and sectors — six sectors, nothing granted until you tick it, read and act together
- MCP tools — the address an agent connects to, and what every call returns
- The OAuth bridge — how a hosted agent signs in, and the eight addresses the internet reaches
- Read data —
get_schema,queryandget_record - Freshness and live reads —
describe_context,fetch_live, and how often Postern checks - Act on a source —
list_actionsandinvoke_action - The audit log — what a row holds, and what gets no row
- Read the record — the ledger screen and
GET /api/audit - What the record cannot promise — what is dropped before it lands, and what nothing in the database prevents
Where things are
- Source code — github.com/getpostern/postern
- Image —
ghcr.io/getpostern/postern, for Intel, AMD and ARM machines - Back up, export and erase
- Frequently asked questions