Stalwart alternative.
Proven email infrastructure, not a rewrite.
Stalwart reimplements email from the ground up in Rust. Vectis Mail runs the engine the internet already trusts — Postfix, Dovecot, Rspamd — and wraps it in a declarative API, updates that automatically roll themselves back, and a support line with an SLA. When what you're choosing is where your company's mail lives, a brand-new codebase is a cost you carry, not a feature you use.
At a glance
The criteria that matter when email is infrastructure for a product or a business. Current as of June 2026.
| Vectis Mail | Stalwart | |
|---|---|---|
| Mail engine | Postfix · Dovecot · Rspamd — battle-tested, production-hardened stack | From-scratch Rust reimplementation |
| Updates | Atomic 6-phase orchestrator — auto-rollback on any failure | Binary / package upgrade |
| Configuration | One declarative config.yaml + vectis apply | TOML files + web admin |
| Transactional sending | Domain-scoped API keys · batch · attachments · per-domain analytics | JMAP + admin API (build it yourself) |
| Webmail | Roundcube bundled, ready on day one | Not bundled today — add and run your own |
| Antispam + antivirus | Rspamd + ClamAV | Built-in classifier; AV via integration |
| IP warmup + deliverability tooling | 30-day warmup ramp · RBL monitoring · per-domain delivery analytics | Not a focus |
| Commercial support + SLA | Pro $39/tenant/mo · Enterprise from $499 with response SLA | Paid Enterprise edition |
| Production track record | Proven components, hardened over decades | Young, rapidly evolving codebase |
| Protocols | SMTP · IMAP · POP3 | + JMAP · CalDAV · CardDAV · WebDAV |
| Calendar / contacts | On the roadmap | Included (groupware) |
| Clustering / storage | Single-node on PostgreSQL | Multi-node; pluggable backends |
Stalwart's extra protocols, groupware and clustering are real — see where they fall outside our scope. For everyone shipping transactional and team email, the top of this table is the list that counts.
Why teams move to Vectis Mail
Vectis Mail fits when…
- You're sending email from an app or product and want the API and the mailboxes on one platform.
- You'd rather run a mail engine proven over two decades than a from-scratch rewrite of every protocol.
- You want updates that snapshot first and roll themselves back on failure — not a binary swap and a prayer.
- You run mail for more than one domain or customer and need domain-scoped keys, analytics and RBAC.
- You want a vendor and a response SLA standing behind your mail, not a community forum.
How they differ
"New" is a cost, not a feature
Stalwart reimplements SMTP, IMAP, POP3, JMAP and the DAV protocols from scratch in Rust. It's genuinely ambitious engineering. But for the thing it does — moving your company's mail — newness cuts the wrong way. Postfix and Dovecot have been delivering internet mail since before most SaaS companies existed; every strange edge case, every malformed message, every deliverability quirk has already been hit and fixed in production a million times over.
Vectis Mail keeps that boring, proven engine and puts the modern surface — Go API, React admin, declarative config, orchestrated updates — around it. You get the developer experience without betting your mail flow on a young reimplementation of protocols that took two decades to harden.
An API key, not a JMAP account
Both have programmatic surfaces, so let's be precise about the difference. Stalwart gives you JMAP and webhooks — powerful, but you're integrating against a mail protocol. Vectis Mail gives you the thing applications actually reach for: a domain-scoped API key and a /send endpoint, with batch sending, attachments, per-domain rate limits, delivery analytics, and HMAC-signed inbound webhooks. It's a SendGrid you host yourself, not a server you have to learn a protocol to talk to.
See the API Reference for the full surface.
Updates that undo themselves
Picture the upgrade going wrong at 2am. On Stalwart, an upgrade is a binary or package swap; if a release misbehaves, recovery is whatever you manage by hand, under pressure. Vectis Mail runs every change through a 6-phase orchestrator — snapshot → migrate → pull → deploy → health-check → complete — and any failure automatically rolls back to the snapshot. The Plan/Apply view shows you the diff before you run it. The difference isn't a feature on a checklist; it's whether a bad release is a non-event or a very bad night.
One honest scope note: groupware and scale-out
Here's the honest part. Vectis Mail is built for mail: sending, mailboxes, deliverability and the API. It doesn't cover in-server CalDAV/CardDAV groupware— or multi-node clustering today. If in-server calendar and contacts, or a multi-node cluster with pluggable storage, are the core of what you're buying, that's a deliberate gap in our scope to weigh before you switch.
But notice what that buyer is doing: replacing Exchange. Most teams reaching for a self-hosted mail server aren't — they're replacing SendGrid plus a pile of mailboxes, and they want it to be simple to run and hard to break. For them, groupware and clustering aren't wins; they're extra surface area to secure, patch and operate. Vectis Mail spends its complexity budget where that buyer needs it: deliverability, the API, and updates that can't take you down.
Migrating from Stalwart to Vectis Mail
It's a standard IMAP-to-IMAP move — both expose IMAP regardless of what's underneath:
- Stand up Vectis Mail on a fresh VPS via the installation guide, with DNS still pointed at Stalwart.
- Sync mailboxes with
imapsyncfrom Stalwart's IMAP to Vectis Mail's Dovecot IMAP. - Generate new DKIM keys on Vectis Mail and publish them alongside the existing ones; run both in parallel during cutover.
- Re-create Sieve filters as needed — both support server-side Sieve.
- Point your app at the Vectis sending API — issue a domain-scoped key and swap the endpoint.
- Cut DNS over: switch MX to Vectis Mail and watch it take over as DNS propagates.
- Verify + decommission after a few clean days.
If you actively use Stalwart's calendar/contacts, plan where those will live first — Vectis focuses on mail, so that's a deliberate scope choice, not a step in the sync.
Frequently asked questions
When is Vectis Mail the right choice over Stalwart?
It depends on what you're building. Stalwart is a from-scratch all-in-one for people who want JMAP and built-in groupware in one Rust binary — closer to an Exchange replacement. Vectis Mail is for teams sending email from an app or a business: the proven Postfix/Dovecot/Rspamd stack, a transactional API with domain-scoped keys, updates that automatically roll back, and a support SLA. If your job is to ship reliable email and have someone to call when it breaks, proven-stack-plus-support is the safer bet.
Does Stalwart have a transactional sending API?
Stalwart exposes JMAP and event webhooks you can build against. Vectis Mail gives you what most apps actually want out of the box: a domain-scoped API key and a/send endpoint, with batch sending, attachments, per-domain rate limits and delivery analytics — a SendGrid you host yourself, not a JMAP server you integrate against.
Does Stalwart include webmail?
Not today. Stalwart doesn't currently bundle a webmail client (its own is on the project's roadmap), so you deploy and maintain something like Roundcube alongside it yourself. Vectis Mail bundles Roundcube with ManageSieve filter management, configured out of the box, so your users have a browser inbox on day one.
What about Stalwart's calendar, contacts and clustering?
Stalwart does include CalDAV/CardDAV groupware and multi-node clustering, and Vectis Mail doesn't cover those today — a deliberate scope choice worth weighing up front. But if you're sending transactional and team email, they're surface area you'll secure, patch and operate while rarely using. Vectis Mail deliberately focuses on the mail — sending, mailboxes, deliverability and the API — on a single-node design that's far simpler to run well.
Why choose Vectis Mail over Stalwart?
Because the engine is proven, not rewritten; because a single config.yamland atomic updates that roll themselves back beat a binary swap and a prayer; because you get a real transactional API, bundled webmail, IP-warmup tracking and per-domain analytics; and because there's a vendor and a support SLA behind it — Pro at $39/tenant/month, Enterprise from $499 — not just a forum.
Try Vectis Mail
Production mail server in minutes — proven stack, modern surface, free to start.
Other Vectis Mail alternatives
Coming from a different stack? Read the comparison that matches it.
vs Mox →
The minimal single-binary server vs the multi-tenant platform you graduate to. Where the line is.
vs Mailcow →
Same Postfix/Dovecot/Rspamd stack, modern surface: declarative YAML, REST API, atomic updates with rollback.
vs SendGrid →
Same API surface, no per-email pricing. Flat pricing covers unlimited sending volume.
vs Postmark →
Flat self-host pricing vs the developer-loved transactional SaaS. Same API, mailboxes included.