# Features

The full list. The [README](../README.md) carries a shorter one.

## Accounts

- **Multiple accounts:** IMAP, POP3 and JMAP, each on its own background
  worker, with a unified *Inboxes* view across all of them.
- **JMAP:** a Stalwart or Fastmail mailbox over the JSON mail protocol,
  including push. See [Configuration](DOCUMENTATION.md#jmap-stalwart-fastmail).
- **OAuth 2.0 sign-in:** Microsoft with Hylki's own app (no GNOME Online
  Accounts needed), Google through GNOME Online Accounts, and custom
  providers over XOAUTH2. See [Configuration](DOCUMENTATION.md#oauth-google--microsoft).
- **GNOME Online Accounts:** import an account already set up in GNOME
  Settings, IMAP and SMTP accounts and Microsoft 365 over Graph included.
  See [Configuration](DOCUMENTATION.md#gnome-online-accounts). Pausing an account's Mail
  service in GNOME Settings pauses it here.
- **Per-alias SMTP:** each address on an account can send through its own
  server and credentials.
- **Any From address:** type a name and address for one message, such as a
  `+tag` address, and replies to a `+tag` address answer from it. A JMAP
  server's own identities are offered too.
- **Proton Bridge, Zimbra, iCloud, Mailfence and other awkward servers:**
  STARTTLS with locally signed certificates, a certificate in the hosting
  company's name rather than yours, servers without MOVE, and non-compliant
  fetch replies are all handled.

## Mail

- **Whole-mailbox sync and search:** no message-count cap. A fast first page
  loads instantly; the rest indexes in the background with infinite scroll.
- **Two-way sync:** deletions, moves and flag changes from your phone or
  another client sync back automatically (IMAP IDLE plus reconciliation).
- **Conversation threading** across folders: the count covers the whole
  conversation, and an expanded conversation shows your replies from Sent
  and its archived messages alongside the folder's own.
- **Moving mail between accounts:** Move To lists every account's folders,
  and mail dragged onto another account's folder goes there too.
- **Full folder management:** create, rename, move, reorder and delete
  folders, assign the special roles (Drafts, Sent, Junk, Trash, Archive),
  and hide the ones you never open. An Exchange server's calendar, contacts
  and task folders are hidden from the start.
- **Filters:** multi-condition rules on sender, recipient, subject, body and
  Reply-To, with comma-separated alternatives, or on whether the sender is in
  your Contacts (the system address books and the Hylki book, not addresses
  collected from mail); they tag mail, file it away, or both, and can be run
  over mail that is already in a folder.
- **Tags:** IMAP keywords, Graph categories, or a local fallback where the
  server has neither; custom colours, drag to reorder, and number-key
  shortcuts. Gmail's labels show beside them.
- **Quick filters:** unread, starred, attachments, addressed to you, from
  your contacts, high importance, tagged and today, combined, in one popover
  above the list with the sort orders. See [Message list layout](DOCUMENTATION.md#message-list-layout).
- **Smart folders:** saved searches across accounts and folders, on
  starred, unread, attachments, tags and the filter conditions, with unread
  counts. See [Smart folders](DOCUMENTATION.md#smart-folders).
- **Unified and filtered folders:** Inboxes, Starred, Sent, Drafts, Archive,
  Junk and Trash across accounts, plus a folder per filter and any folders
  you keep in Favorites.
- **Empty Trash and Junk**, by hand or automatically after a number of days,
  and move old newsletter and mailing-list mail out of the Inbox the same way.
- **Attachment gallery:** every attachment in an account or folder in one
  place, with PDF first-page thumbnails, scoped by account and folder, and a
  deep archive scan that finds old attachments without downloading them.
- **Delete an attachment from the server:** take a large file out of a
  message and keep the rest of it, on IMAP, JMAP and Microsoft 365.
- **Printing:** a message with its sender, recipients and date, page
  numbers and an optional wider margin for hole punching, with an in-app
  preview that also saves straight to PDF.
- **Outbox:** a send that fails is kept and retried when the connection
  returns, not lost. Queued messages can be edited, sent by hand or discarded.
- **Send later:** schedule a message for tomorrow morning, Monday, or any
  date and time; it waits in the Outbox, editable, until then.

## Writing

- **Four formats:** rich text, Markdown, hand-written HTML, or plain text,
  switched per message from the composer's format button. See
  [Writing in Markdown or HTML](DOCUMENTATION.md#writing-in-markdown-or-html).
  Rich text has fonts, sizes, any color, headings, lists and pictures, and
  is sent as HTML.
- **HTML signatures**, several per account, picked by name in the composer,
  with a default sender for new mail. In a reply or forward the signature
  sits above the quoted message, or below it if you prefer.
- **Drafts** that can be saved without a recipient, reopened inline, and
  deleted from the composer.
- **Templates:** save a message as a template and start new ones from it,
  from the Templates folder or with Ctrl+Shift+N. Thunderbird's Templates
  folder is picked up as it is.
- **Forwarding keeps the attachments:** the original's files are attached to
  the forward, ready to send on. A reply does not repeat them.
- **Inline images:** dropped, pasted or picked from a file manager, resized
  by handle or menu, with an optional recompress on send.
- **Spell check** in one language or several at once, through the system
  dictionaries.
- **Undo and redo** across the whole message.
- **Quote folding:** a long quoted original folds away, interleaved replies
  intact.
- **Split reply:** answer one message of a conversation with the rest still
  on screen.
- **Cloud attachments:** upload a large file to your own Nextcloud,
  ownCloud, OpenCloud or Seafile server, or to OneDrive or Dropbox, and put a
  share link in the message, with an optional expiry and download password.
  See [Cloud attachments](DOCUMENTATION.md#cloud-attachments-nextcloud-onedrive-dropbox-seafile).
- **Drag files in:** dragged over the composer, files can be attached, put
  in the text or uploaded to cloud storage; dragged over the window, they
  start a new message in any of those three ways.
- **Send from Files:** a *Send with Hylki* entry in the GNOME Files
  right-click menu sends the selected files into a new message, a draft or a
  reply of your choosing, with an offer to upload big ones to cloud storage
  instead. See [Send with Hylki from GNOME Files](DOCUMENTATION.md#send-with-hylki-from-gnome-files).

## Reading

- **Privacy-first reading:** remote content blocked by default, per-sender
  allow and block lists, and a per-message light/dark content theme.
- **Reader View:** one toggle shows every message in the conversation as its
  content alone: the sender's layout tables, colours, fonts, hidden preview
  text and tracking pixels are stripped, and what is left is set in one
  uniform sheet that follows the app's theme.
- **Your own font and colours** for message bodies, overriding the sender's.
- **Message zoom:** Ctrl++ and Ctrl+- scale the message alone, in Reader
  View or out of it, with the percentage shown beside the Reader View switch
  while it is away from the default. Settings → Reading sets the zoom every
  launch starts at; Ctrl+0, or a click on the chip, returns to it.
- **Meeting invitations:** what the meeting is, when it runs in your own
  clock and time zone, where it is and who organised it, with Accept, Maybe,
  Decline and Add to Calendar.
- **Folding conversations:** a click on a message's header folds it to its
  sender and first lines, and earlier messages can start folded, so
  a long conversation opens on what is new.
- **Translation:** with a DeepL, Google, Microsoft or LibreTranslate key of
  your own, a message is translated in place, and switched back to the
  original with a click. A message in another language can offer it; the
  language is recognised offline. In the composer, what you write goes into
  the language of the message you are answering. See
  [Translating messages](DOCUMENTATION.md#translating-messages).
- **One-click unsubscribe:** a banner on list mail that leaves the list for
  you, by request or by email, without a browser where the list allows it,
  and can delete the mail already received from the same address.
- **OpenPGP:** read encrypted and signed mail, sign and encrypt what you
  send, and manage keys from Settings, through the GnuPG already on your
  computer. See [OpenPGP](DOCUMENTATION.md#openpgp-encrypted-and-signed-mail).
- **Sender identity:** DKIM, SPF and DMARC checked on arrival, with BIMI
  logos where a domain publishes one.
- **Message previews:** the first one to three lines of each message under
  its subject in the list, or off.
- **mid: links:** a link to another message opens it (RFC 2392).

## The app

- **GNOME-native:** adaptive three-pane layout, per-account colours and
  emoji, picture or Gravatar avatars, light and dark following the system.
- **Appearance themes:** five palettes (Rose, Forest, Tidal, Earth and
  Midnight), each with its own light and dark version, or the stock GNOME
  colours.
- **Focus Mode:** Ctrl+Shift+F folds the toolbars, sidebar and list down to
  what you are reading, and puts it back afterwards.
- **A customizable reader toolbar:** reorder its buttons, or drag them in and
  out, in Settings → Appearance.
- **A single-line message list:** sender, subject and the start of the
  text on one line per message, always, or whenever the list pane is
  dragged wide.
- **Swipe actions** on message rows, with an adjustable sensitivity.
- **Single-key shortcuts:** Gmail-style `j`/`k`, `r`, `a`, `d` and friends,
  without a modifier. See [Keyboard shortcuts](KEYBOARD_SHORTCUTS.md).
- **Runs in the background** (optional): closing the window keeps mail
  arriving; Hylki appears under *Background Apps* in the GNOME system menu,
  and can start at login without opening a window.
- **Tray icon** (optional): a StatusNotifierItem with a count of the folders
  you choose.
- **Notifications** that open the message they are about, with up to three
  buttons of your choice: Mark as Read, Archive, Delete, Reply, Forward or
  Mark as Spam, and a sound if you want one: built in, or a file of your own.
- **GNOME Contacts:** names and photos from your address book, optional.
- **Hylki address book:** a book of your own, beside the ones Evolution Data
  Server keeps, with vCard (`.vcf`) import. It works without GNOME.
- **LDAP directories:** recipients looked up in a company directory as you
  type, through Evolution Data Server, and in a Microsoft 365
  organization's directory.
- **Your language:** the desktop's, or one you pick; a 12- or 24-hour clock
  following the desktop setting.