Every Fastmail account. One inbox. And every mail you ever got, found in a second.
Opensolr Mail is a free, open source Android client for people who live in more than one Fastmail account. One unified inbox, conversations in threads, notifications you can act on, your Fastmail Notes and calendars — and a search that understands what you mean, reads the text inside your attachments and answers your question from your own mail.
Free and open source under the MIT license. Android 8.0 or newer and a Fastmail account. Search runs in your own Opensolr Index, on the free Opensolr account — no card, no expiry. Create one when you want search.
Six problems. One app.
Opensolr Mail was written for one kind of person: the one with a personal Fastmail, a work Fastmail and two more domains on the side, who is tired of switching between them and of not finding the mail that was definitely there.
1 · Several Fastmail accounts, one inbox
Work, personal, the side project, the family domain. Every inbox, every Sent and Drafts folder, every Archive, all in one list, instead of switching from one account to the next and missing the mail that landed in the other one.
2 · Mail you can actually find
Type what you remember, not the exact words. Search matches the words and the meaning together, so “the quote for the new roof” finds the mail that said “estimate for replacing the shingles”. An AI answer on top reads your own results and tells you what they say.
3 · The invoice inside the PDF
The number you remember is printed inside an attachment, not in the mail. On Wi-Fi the app reads the text of PDFs, Office documents and pictures, so a search finds the invoice by the number, the total or the name printed in it.
4 · Push you can act on
New mail shows up the moment it arrives, with exactly three buttons: Mark as read, Delete and Reply all, typed right in the notification. Most mail never needs the app opened at all.
5 · Fastmail, done natively
Your Fastmail password and two-factor code, on Fastmail’s own page. No IMAP settings, no app passwords. Your Fastmail Notes are in the app, and your Fastmail calendars sync into the phone’s calendar.
6 · Nothing you have to take on trust
Every line is on GitHub under the MIT licence. Your search lives in an Opensolr Index that belongs to your account, and the app runs without an Opensolr account at all if all you want is the inbox.
Your accounts go in. One inbox comes out.
Sign in to Fastmail and the inbox is there. Connect an Opensolr account and every message is indexed in the background, newest first, into an index that belongs to you. Nothing to configure on either side.
- Sign in to FastmailFastmail’s own sign-in page opens in your browser, with your password and your two-factor code. The app never sees your password and needs no app password. Add as many accounts as you have.
- Read, reply, get on with your dayThe unified inbox fills at once. New mail arrives with a notification you can answer from.
- Connect Opensolr when you want searchOne more sign-in, in the browser. The app creates your mail index, reads your whole history into it in the background, and keeps it in step with every new, moved or deleted message.
- SearchType what you remember. Words and meaning are matched together, an AI answer sums up what your results say, and filters narrow it down.
“What did the accountant say about the March invoice?”
Ask it like that. The same hybrid search that runs Opensolr’s site search matches your words and what they mean, across every account at once, and an AI answer reads the best results and tells you. Your mail is searched in your own Opensolr Index, never in a shared one.
What it finds
Words and meaning, in the mail and in what is attached to it.
- By meaning. “flight tickets” finds the boarding pass that never used the word ticket.
- By the exact word. A code, an order number, a name: switch AI off and the search matches words only.
- Inside attachments. On Wi-Fi, PDFs, Word, Excel, PowerPoint, OpenDocument, RTF and pictures are read into text. Archives are never opened.
- An AI answer. One tap and the best results are read and summed up, from your mail and nothing else.
- Fresh first. The Fresh switch pushes recent mail up hard, for when you know it was last week.
How you narrow it down
Filters and groups built from your own mail.
- From and To, each person with their address, one line per address.
- Company, account, folder, year, weekday and the type of attachment.
- Any two days on a calendar, and switches for unread, flagged, answered, with attachments and with attachment text.
- Grouped by day, month, sender, company or account, every group folding and remembered.
- Your balance. A slider in Settings decides how much meaning and how much exact words count.
A mail client, compact and quick.
Flat, dense, no wasted space. Every list remembers where you were, every fold stays folded, and every action answers with a small tap you can feel.
One inbox for every account
All Inboxes, All Drafts, All Sent, All Archive, All Junk, All Trash and Flagged, across every Fastmail account you add, with each account’s own folders under it. With more than one account, a thin coloured stripe on each message tells you which one it came to.
Conversations in threads
A reply sits with the mail it answers. Open a conversation and every message is there, each one opening with a tap, with Reply, Reply all, Forward and Copy on each. Tap a name or an address to copy it; save any attachment to the phone.
Grouped the way you think
The list is grouped by day, by default, or by month, sender, company or account. Every group folds, the app remembers which ones you folded, and one button folds or opens them all.
Swipe, select, done
Swipe left to delete, right to flag. Press and hold to select several conversations and mark them read, flag, archive or delete them together. Every action gives a small tap back you can feel.
Mark all as read, empty the bin
One button marks a whole inbox as read, or all of them at once. Press and hold Trash or Junk and empty it for good, on Fastmail too, after a second tap to be sure.
Notifications with three buttons
Mark as read, Delete, Reply all. The reply is typed in the notification and goes to everyone on the thread. Nothing else, on purpose.
Search that remembers where you were
Your query, your filters, your grouping and where you had scrolled to stay exactly as you left them, for the whole time the app is open. A fast scroller with a tap at every date you pass gets you through years of mail in a second.
Fastmail Notes
The notes you keep in Fastmail, read, written, pinned and deleted in the app.
Your calendars, in your calendar
Each account’s Fastmail calendars sync both ways into Android’s calendar, so Google Calendar, or any calendar app, shows and edits them. Switch it on or off per account.
Seven languages
English, Deutsch, Français, Español, Română, 日本語 and 中文, following the phone or chosen in Settings.
Updates itself
Once a day the app looks for a new release on GitHub. When there is one, it downloads it, checks that it carries the same signature and is really newer, and hands it to Android’s installer.
Between Fastmail, your phone and your own index.
Where your mail goes
And only there.
- Fastmail keeps your mail, as it always did. The app talks to it directly.
- The phone keeps a local copy for the inbox, so lists open at once.
- Your Opensolr Index, only if you connect one, holds the text of your messages for search. It is yours: see it, back it up or empty it from the Opensolr control panel.
- No ads, no analytics, no tracking. Nothing else is contacted.
How it is protected
Checked at every step, and readable in the source.
- Browser sign-in for Fastmail and Opensolr: your passwords and two-factor codes stay in the browser.
- Encrypted on the phone with a key held by Android’s secure key store, and never in phone backups.
- Encrypted push. Fastmail encrypts every push with a key that never leaves your phone; the relay that wakes the phone passes it on without being able to read it.
- HTTPS only, for every connection the app makes.
A Fastmail account. Opensolr when you want search.
The free Opensolr account runs search, search by meaning included, with no card and no expiry. A paid plan buys more room and more AI requests a month. The app shows your real numbers in Settings, with a link to upgrade.
Disk space and bandwidth
How much mail the index holds and how much searching it serves in a month. At either limit Opensolr closes the index, and search and indexing stop until you upgrade or, for bandwidth, the month resets.
AI requests per month
Used for meaning, for the AI answer and for reading attachments. When they run out, search goes on by words only until the month resets; new mail gets its meaning later.
Without an Opensolr account
The inbox, notifications, notes and calendars all work. There is no search, and new mail is checked every 15 minutes instead of arriving at once.
Every line is on GitHub.
Opensolr Mail is MIT licensed. Read how it signs in, how it syncs and exactly what it sends where, build the APK yourself, or fork it and make it yours.
Source code
Kotlin and Jetpack Compose. github.com/phpcip/opensolr-mail
Documentation
Installing, signing in, the inbox, notifications, search, notes and calendars, your Opensolr account, privacy. Read the documentation
Releases
Every version with its signed APK and release notes. All releases
Four steps, about a minute.
- Download the APK on your phoneopensolr-mail.apk, the latest signed release from GitHub.
- Allow the installAndroid asks once whether your browser may install apps. Allow it for this install.
- Open Opensolr Mail and sign in to FastmailAdd your other Fastmail accounts in Settings.
- Connect Opensolr for searchNow or later, from search or from Settings. No account yet? Create one, free.
All your Fastmail. One inbox. Found in a second.
Free, open source, every account in one place, and a search that understands what you mean and reads inside your attachments. On a free Opensolr account that never expires — need more? See the plans.