Who builds this
Missivus is a Solvetus Labs project — the open-source arm of Solvetus, a European studio that builds and runs privacy-first websites and self-hosted infrastructure for small organisations.
Why it exists
Missivus started the way most honest tools do — as a problem we had ourselves. Our own self-hosted Matomo stopped sending scheduled reports when basic-auth SMTP was switched off in our Microsoft 365 tenant — the default every tenant reaches at the end of December 2026, and every documented workaround was either a paid extension, a person's mailbox pressed into server duty, or a third-party relay we would then have to explain in a privacy policy.
The correct route — Graph with application permissions, scoped by an Exchange access policy to one free shared mailbox — was well documented by Microsoft and implemented by almost nobody. So we implemented it, hardened it, had it reviewed, and released it under the GPLv3.
The model is deliberately simple — the software is free and stays free, for everyone, forever. Solvetus earns money installing and supporting it for organisations that would rather spend thirty minutes of someone else's time than their own.
Why Missivus
From the Latin missivus, 'sent, dispatched', the root of missive: a letter sent on someone's behalf. That is exactly what the software does — it carries mail on behalf of an application, not a person, and it is why the family name works for every platform. The lowercase wordmark and the M mark with its single dot are the envelope and the one thing inside it. A Solvetus Labs project — Solvetus, 'solved', is the sibling name.
How we work
Privacy first, structurally
This very site makes zero third-party requests, sets zero cookies, and honours GPC and DNT at the edge — claims you can verify in your browser's network tab, not promises in a banner.
Free means free
GPLv3, no paid tier, no feature gate, no telemetry. The commercial offer is human time, never software keys.
Boring where it matters
Mail transport is infrastructure. It should be reviewed, documented, and unexciting — surprises belong in release notes, not inboxes.
The studio behind it
Solvetus builds privacy-first websites, self-hosted analytics and small-scale infrastructure for European clients — and maintains Missivus as free software under its Labs banner.