SMF·FASTMAIL
Can a prompt replace Fastmail?
Email — email clients and hosted mail
Exhibit tracking slip
Verdict
Running your own mail server — SPF, DKIM, DMARC, IP reputation, spam filtering — is one of the few things in this whole catalogue that is flatly not a weekend project, and Fastmail's actual product is hosting that well. What you can build in a weekend is the client: connect to any IMAP/SMTP mailbox, including one you still pay Fastmail (or another host) for, with fast local search and no bloat.
Exhibit A — The prompt
Received on31.07.2026Build a lightweight desktop email client for a mailbox you already own — this does not replace hosting your own mail, which is explicitly out of scope (DNS/SPF/DKIM and spam-fighting is not a realistic solo project; keep paying someone, whether that's Fastmail or another IMAP host, for the actual mailbox). Use Tauri or Electron with a local SQLite index. Connect via IMAP and SMTP with a username/password or app-specific password — no OAuth app registration needed. On first run, do a full header sync, then keep syncing incrementally with IMAP IDLE or short polling. Support folders, a unified view of one connected account, full-text local search over subjects and bodies, and standard reply/reply-all/forward/compose with plain-text and simple HTML. Keep drafts locally until sent. Do not build multi-account support, calendar/contacts, or any server-side component — this is a single-account local client, nothing more. No external API key needed; only the mailbox credentials you already have.Opening prefills the prompt — press enter to run it.
Exhibit B — What you lose
- B.1 actually hosting your own mail (still needed from someone)
- B.2 spam filtering tuned over years
- B.3 calendar and contacts sync
- B.4 custom-domain mailbox management
Prior art
Exhibit C — Why people still pay: mail infrastructure, integrations, and client polish
The email client is the easy 5%; the subscription is for the hard-won 95% — not ending up in spam, keeping a domain's sending reputation clean, and never losing mail.
Questions
Do I still need to pay for mail hosting?
Yes — this replaces the client, not the mailbox. Running your own reliable mail server is genuinely not a weekend project; keep paying Fastmail, or any IMAP host, for that part.
Why build a client at all if I'm still paying for hosting?
Because the client is the part with real day-to-day lock-in — search speed, keyboard flow, how fast it feels. The hosting underneath can stay boring and cheap.
Does it handle multiple accounts?
No, this build is scoped to one account on purpose. Multi-account support is real engineering work this prompt deliberately skips.
What about calendar and contacts?
Not included. Fastmail bundles those; this build is email only.
Related tools
Receipt