The blog

Notes from the office

Product updates, postmortems, and occasional rants about email. Subscribe via RSS or the monthly newsletter.

Why we built Mailcedar

A few people have asked recently whether the world really needs another email service. Three years in, here's the honest answer.

What we mean (and don't mean) when we say "encrypted"

There's a lot of marketing around email encryption that doesn't match reality. Here's a plain-language walk through how Mailcedar actually handles the cryptography, and what email's underlying protocols make impossible.

2025: a year in numbers

The numbers we promised to publish every year — revenue, costs, paid accounts, complaints, and what surprised us. Plus what we're planning for 2026.

Faster search, less memory

A small writeup of the indexing rewrite that landed last week. Search across a 30 GB mailbox now returns in under 200ms — down from the four seconds it used to take on Plus accounts.

Cure53 audit: what they found and what we fixed

The annual penetration test wrapped two weeks ago. Three medium findings, one low, no highs or criticals. Here's the summary report and our response.

No, we're not adding AI to your inbox

A few customers have asked. The answer is no, and here's the long-form version of why. Short version: AI in your inbox means AI reading your inbox.

Sieve filters that don't make you cry

A new visual editor for Sieve scripts shipped last week. We built it because we kept watching support sessions where users wanted complex routing and got stuck on syntax. Now they don't.

Six months on bare metal

We moved off AWS in November 2024. Six months later, the new servers are paying for themselves and the inbox latency is down 60%. Here's how we did it, what broke, and the spreadsheets that justified the migration.

The monthly note

One short email a month — what shipped, what we're thinking about. No marketing.