Try the demo
_{A working copy with an invented mailbox behind it — no sign-up, nothing real, nothing kept.}

ihasmail

Immutable webmail for Stalwart Mail Server — a container with nothing to persist, and a Gmail-class client on top of it.

Mail, calendars, contacts, files and filters in a responsive single-page app that works equally well on a desktop monitor and a phone. It talks only JMAP (plus Stalwart's blob/upload/EventSource endpoints) — no IMAP, no SMTP, no database, and with IMMUTABLE=1 no writable filesystem either. Everything durable belongs to Stalwart; the container is disposable.

🌐 ihasmail.org	What it is, what it looks like, the full feature list
📘 docs.ihasmail.org	Installing · Configuring · Using it · Shortcuts · Rebranding · Troubleshooting
📋 FEATURES.md	Everything it does, feature by feature, with the capability each one needs
🧪 KNOWN-ISSUES.md	What was verified live, and where Stalwart departs from a spec
🛣 ROADMAP.md	What ihasmail does not do, and why

This file is for people working on ihasmail. Everything about running it lives in the docs.

Screenshots

Taken against the built-in mock server (npm run dev:mock) with sample data — no real mailbox involved.

Inbox & conversation (dark)	Inbox & conversation (light)
Composer	Calendar
Contacts	Sieve filter builder

More, including the mobile layout, on ihasmail.org.

What's in it

• Mail — three-pane Gmail-style layout, conversation view, virtualised list, labels, undo, Gmail search operators and keyboard shortcuts, Sieve rules from a message's context menu, sanitised HTML with remote images blocked, read receipts, invitations and RSVP, an event made from a message with its guests already in it, multi-composer rich-text editing with signatures, scheduled send and undo send
• Calendar — JMAP Calendars / JSCalendar: month/week/day/agenda, recurrence, attendees and free-busy, colour categories
• Contacts — JMAP Contacts / JSContact: address books, groups, full editor, vCard import/export
• Files — JMAP FileNode: browse, upload, download, rename, move, delete
• Settings that follow the account, not the browser — kept in a settings.json in the account's own JMAP Files, so ihasmail itself stays stateless
• Runs read-only — one optional write path, and with it switched off the container needs no volume and no writable root. IMMUTABLE=1 is checked at startup rather than trusted, so a half-applied switch refuses to boot instead of failing quietly. See Running immutably
• Nine new interface languages — German, Spanish, French, Dutch, Portuguese (Brazil), Russian, Ukrainian, Simplified Chinese and Japanese, alongside English and separate from the date-and-time locale. Every one is marked Beta: they were made by AI and no native speaker has read them yet, which Settings says plainly, with a link for reporting anything wrong
• On a phone — swipe a message to archive or delete it (either direction, your choice), hold one to select it, hold a folder for its menu, pull the list to refresh, swipe back from a conversation
• Platform — installable PWA, Web Push with ihasmail closed, mailto: handler, no credentials in the browser, strict CSP, SSRF-safe image proxy

The long version is on ihasmail.org; how to drive each one is in Using ihasmail.

Requires Stalwart 0.16 or newer

Sign-in refuses anything older, by name. 0.16 replaced the REST management API with JMAP registry objects, changed the shape of FileNode, split its rights up and moved configuration into the store; supporting both generations meant a wrong guess had somewhere to fall back to, so it failed quietly — and that reached production. With one supported generation a wrong guess is a loud error on the first call.

• Still on 0.15? The last release that runs on it is tagged stalwart-0.15-support.
• Upgrading? stalwart-migrator does it in place, checkpointing every phase and validating afterwards. The live instance moved 0.15.5 → 0.16.19 with eight seconds of downtime and nothing lost.

Quick start (Docker)

cp .env.example .env
# edit: STALWART_URL=https://mail.example.com  and  APP_SECRET=$(openssl rand -base64 48)
docker compose up --build -d
# → http://localhost:8080  (put Caddy/nginx in front for TLS; see Caddyfile.example / nginx.example.conf)

Users sign in with their Stalwart mailbox credentials. An account with two-factor authentication needs an app password, created in Stalwart's own settings — Stalwart accepts a TOTP code only through an OAuth flow and offers no password grant, so no client holding a username and password can exchange them plus a code for a token.

Full instructions, TLS, and every environment variable: Installing · Configuring.

Running immutably

The server writes to exactly one path, the optional SESSION_FILE. Clear it and there is nothing left to write, so the container can run with no writable filesystem at all:

docker run --read-only --tmpfs /tmp -e IMMUTABLE=1 -e SESSION_FILE= ...

IMMUTABLE=1 is an assertion the server checks at startup rather than a switch that changes what it does: it refuses to start if SESSION_FILE is still set, or if the filesystem it is installed on turns out to be writable after all. Without it the same misconfiguration is silent — sessions are held in memory and persisting them is best-effort, so a read-only /data costs one warning at the first sign-in and nothing else until the instance is replaced and everyone is signed out.

That sign-out is the standing cost of this mode today, since sessions have nowhere to live across a restart. Removing it means moving the session upstream into a token Stalwart itself issues and can revoke, which is what the OAuth work in ROADMAP.md is for.

Architecture

browser  ──(same-origin /api/*)──►  ihasmail server (Node + Hono)  ──(JMAP over HTTPS)──►  Stalwart
  React SPA                           • session cookie ⇄ Basic auth
  JMAP client + stores                • /api/jmap, /api/blob, /api/upload, /api/events (SSE), /api/image

• web/ — Vite + React 19 + TypeScript SPA. src/jmap (client, push, types), src/store (zustand: session, mail, compose, contacts, calendar, files, sieve, settings), src/views, src/lib (sanitiser, search parser, Sieve codec, locale-aware dates, vCard, …).
• server/ — Node/Hono backend: authenticates against Stalwart's JMAP session endpoint, seals the credentials with a key derived from the cookie secret, proxies JMAP/blob/SSE, serves the SPA under a strict CSP. src/mock/ is an in-memory fake Stalwart for development and demos.

Capabilities used: core, mail, submission, vacationresponse, sieve, contacts(+parse), calendars(+parse), principals(+availability), quota, blob, filenode, EventSource push, plus Stalwart's own urn:stalwart:jmap (read-only). Features degrade gracefully when one is missing.

Development

Requirements: Node ≥ 20.10 (22 recommended), npm ≥ 10.

npm install

npm run dev            # real Stalwart (STALWART_URL in .env) — server :8080, Vite :5173
npm run dev:mock       # built-in mock Stalwart ([email protected] / demo), mock on :8788
npm run dev:mock:no-future-release   # mock that advertises FUTURERELEASE and drops every hold

npm run typecheck      # tsc for both packages
npm test               # vitest (web) + node:test (server)
npm run build          # web/dist + server/dist
npm start              # serve the production build

Open http://localhost:5173 in dev, or http://localhost:8080 for the production build. Running it for real is covered in Installing and Configuring.

The mock

An in-memory fake Stalwart 0.16 — enough JMAP to develop and demo against without a real mailbox. It reproduces the things a naive fake would get wrong, because each cost a live debugging session: urn:stalwart:jmap advertised per-account rather than session-level, identity signatures capped at 2047 bytes, and CalendarEvent/set speaking Stalwart's vocabulary rather than RFC 8984's. Two switches: MOCK_NO_FUTURE_RELEASE=1 advertises FUTURERELEASE and then drops every hold; MOCK_NO_REGISTRY=1 omits the Stalwart capability so the sign-in refusal can be tested.

Version numbers

ihasmail v2026.8.30+pr129 — the date of the commit this was built from, and the pull request that commit arrived through. A commit that did not arrive through one carries its short SHA instead: 2026.8.30+g1fa6578. It all comes from git at build time; nothing writes a version into the tree, and package.json sits at 0.0.0 because it is no longer the source of anything.

The date is the commit's own rather than today's, so rebuilding an old commit gives the version it had the first time.

node scripts/version.mjs        # the version for the current checkout
docker build --build-arg IHASMAIL_VERSION="$(node scripts/version.mjs)" -t ihasmail:2026.8.30 .

.dockerignore excludes .git deliberately, so an image build cannot work this out for itself — pass it in. Left out, the build reports 0.0.0, which is meant to look wrong: a version with no +pr or +g means whoever built the image did not pass one.

The version says nothing about Stalwart, deliberately. It used to: 2.16.x had 16 for the 0.16 generation it targeted, which leaves nowhere to go once Stalwart reaches 1.0 — 2.1 sorts below the 2.16 already deployed, so every image and About screen would read as a downgrade. Which Stalwart a build needs is stated where it can be precise, in the badge at the top of this file and in KNOWN-ISSUES.md, rather than compressed into one digit.

The pull request lives after the +, as build metadata, because it is provenance rather than a rank: at the rate they merge here it climbs without bound and says nothing about how new a build is. Everything after the + is ignored when versions are compared, which is the right reading — two builds from the same day differ in where they came from, not in age. Nothing here depends on that comparison: images are pruned oldest-first by creation time, and a rollback names a git ref.

Deploying

deploy.example.sh is a single-host Docker deploy: it fetches, refuses anything held back by .deploy-hold, shows what is about to be introduced and asks, rebuilds with the right version baked in, replaces the container, waits for healthy, then prunes all but the newest IHASMAIL_KEEP_VERSIONS images — never the one actually running.

./deploy.sh                 # origin/main, asks before shipping new commits
./deploy.sh --dry-run       # run the guards and stop
./deploy.sh v2026.8.30 --yes  # a named ref, no prompt (there is no tty over ssh)

--yes does not override a hold; clearing one means deleting its line.

Contributing

CONTRIBUTING.md · CODE_OF_CONDUCT.md · SECURITY.md — please report vulnerabilities privately.

License

Copyright (C) 2026 Coffey Labs — AGPL-3.0-or-later. See LICENSE.

ihasmail was relicensed from GPL-3.0 to AGPL-3.0 on 2026-08-25: webmail is nearly always run as a network service rather than handed to anyone as a binary, and the AGPL's section 13 closes that gap.

That offer has to point at your source, not this one. If you run a modified ihasmail, set SOURCE_URL to your own repository — the sign-in page and Settings › About both show it. See Rebranding.