Name: DeadLetter
Author: Locke Werks

Overview

What DeadLetter does.

DeadLetter is a desktop email client, in the same category as Thunderbird, Outlook, or Apple Mail. You install it on your own computer and connect the mail accounts you already own. It then does what a mail client does: downloads your messages, shows them in an inbox, lets you read, search, reply, compose, send, organize, and archive.

It handles more than one account at a time. A personal Gmail account, a work Microsoft 365 account, and a self-hosted IMAP server can all appear in a single unified inbox, with conversation threading, full-text search across everything, and per-account color coding so you can tell them apart.

It also shows the calendar attached to each account. Meeting invitations that arrive as email are rendered as invitations, and you can accept, decline, or create events without switching to another application.

The difference from most mail clients is where the data goes. DeadLetter has no backend. It talks directly from your computer to your mail provider, and everything it stores, it stores on your disk. Locke Werks operates no server that touches your mail, and receives nothing about you or your use of the application.

Google Account Access

How DeadLetter uses your Google data.

If you connect a Gmail or Google Workspace account, DeadLetter asks Google for permission to act on that account on your behalf. It requests two permissions, and it uses them only to provide the mail and calendar features described on this page. Below is every permission requested and the exact reason it is needed.

https://www.googleapis.com/auth/gmail.modify

Read, send, and organize your mail

DeadLetter is a full email client, so it needs to read your messages to display them, build the local search index, and cache them for offline reading. It needs to send the messages you compose. It needs to write back the changes you make in the interface: marking read or unread, starring, archiving, moving between folders, and applying labels. This permission deliberately does not allow permanent deletion of your mail, which is why it is requested instead of full Gmail access.

https://www.googleapis.com/auth/calendar

Show and manage the calendar on that account

DeadLetter displays the calendar belonging to each connected account alongside its mail, renders meeting invitations that arrive as email, and lets you accept, decline, and create events from inside the client. The full calendar permission is requested rather than the narrower events-only permission because reading and writing calendar sharing settings requires it, and discovering that later would force you through a second consent prompt.

Limited Use disclosure

DeadLetter's use and transfer of information received from Google APIs to any other app will adhere to the Google API Services User Data Policy, including the Limited Use requirements.

Specifically, and without exception:

Google user data is used only to provide the mail and calendar features you see in the application.
Google user data is never transferred to Locke Werks or to any third party. It moves between Google and your own computer and nowhere else.
Google user data is never used for advertising, marketing, profiling, or resale.
No human at Locke Werks reads your Google user data. There is no mechanism by which we could: it never reaches us.
Google user data is never used to train any machine learning or artificial intelligence model.

You can revoke DeadLetter's access to your Google account at any time from your Google account permissions page, or by removing the account inside the application, which deletes the stored tokens and the local copy of that account's mail.

Data Handling

Where your data actually lives.

DeadLetter collects nothing. Not usage statistics, not crash reports, not analytics, not an install ping. Your data stays yours, on your machine.

No Locke Werks server

DeadLetter has no backend service. The application on your computer connects directly to Google, Microsoft, or your own IMAP host. Your mail never passes through infrastructure we operate, because there is none.

No telemetry, no analytics

The application sends no usage data, no crash reports, no feature metrics, and no install or launch pings. There is no opt-out because there is nothing to opt out of. The source is public and you can verify this yourself.

Mail cached on your disk

Messages, attachments, and the full-text search index live in a local database in your own user profile. That local cache is what makes offline reading and instant search work. Deleting an account from the client deletes its cache.

Tokens in your OS keystore

OAuth tokens and passwords are held by the operating system credential store, never in plaintext and never in the application database: Credential Manager on Windows, Keychain on macOS, and the Secret Service via libsecret on Linux.

Sign-in goes straight to the provider

Connecting a Google account opens Google's own sign-in page in your browser using OAuth 2.0 with PKCE. You type your password to Google, not to us. DeadLetter never sees your Google password.

Auditable by anyone

DeadLetter is released under GPL-3.0 with the complete source public on GitHub. Every claim on this page can be checked against the code, and you can build the application yourself if you would rather not trust our binaries.

Features

What you get.

PGP and S/MIME

Sign, encrypt, and verify messages with OpenPGP or S/MIME. Encryption is built into the message pipeline rather than added as a plugin.

Unified inbox

One virtual folder across every connected account, with conversation threading, an unread-only toggle, and per-account color coding.

Tracker blocking

HTML mail renders in a sandbox with remote content blocked by default, so tracking pixels never report that you opened a message.

Full-text search

A local SQLite index over every message. Search subjects, bodies, and senders across all accounts at once, instantly and offline.

Rules and snippets

Filter inbound mail by sender, domain, or subject to archive, delete, or mark read. Reusable text blocks insert straight into a compose window.

Works offline

The full local cache means you can read, search, and compose without a connection. Queued actions run when you reconnect.

DeadLetter

What DeadLetter does.

How DeadLetter uses your Google data.

Limited Use disclosure

Where your data actually lives.

What you get.

One client. Every provider.

Install it.

Questions and problems.