Conversation tree
Replies, forwards and branches drawn as a real tree, with received and sent marked on every node. See where the thread split, which branch went quiet, and which one carried the decision.
For freelancers, consultants and solo operators
Your mail is a tree. Read it like one.
The mail client that draws the whole conversation.
Someone replies to an older message. A colleague forwards it on. It comes back with the subject line changed. Every mail client flattens that into a list and loses the shape of it. PaperPlane draws the conversation tree — who replied to whom, where it branched, and where each branch stopped.
Windows 10 / 11 · No card required for the trial
Three lines that say what PaperPlane is
- Mail conversations are trees. Every client shows them as a list, and the branch where the decision was actually made is the one you scroll past.
- PaperPlane draws the tree — and lets you widen it from one thread to a whole subject, person, host or domain, so a conversation that moved to a new subject line stays one conversation.
- It talks to your provider straight from your own machine — Gmail, Microsoft 365, iCloud, Yahoo, any IMAP server. No server of ours sits in the path of your mail.
// what it does
One conversation, drawn properly
Everything a mail client should do, PaperPlane does. This is the part that is different.
Widen the scope
One conversation is rarely one thread. Widen the tree from this conversation to this subject, this person, this host, or this whole domain — and watch the scattered pieces join back up.
Built from headers, not guesswork
The tree is reconstructed from Message-Id, In-Reply-To and References — the same data mail servers use to route replies. When a client strips those, PaperPlane falls back to subject and participants rather than inventing a link.
Bulk mail stays out of the tree
A newsletter sent to a thousand people is not a conversation. PaperPlane recognises bulk and no-reply mail and keeps it from collapsing into one fake thread that buries the real ones.
Every account, one inbox
Gmail and Microsoft 365 through OAuth, iCloud and Yahoo through app passwords, everything else over plain IMAP and SMTP. Merged into one list — and the tree spans them, so a thread that moved to your other address is still one tree.
Local, private, quick
Messages are cached in a local SQLite database, so the list opens instantly and still works on a plane. Remote images are blocked until you ask for them, and credentials are sealed with Windows DPAPI.
// how it works
Three steps, then it stays out of your way
- 1
Connect your accounts
Sign in to Gmail or Microsoft 365 with one click, or type in IMAP settings for anything else. Add as many accounts as you have — there is no per-account charge.
- 2
Let it read the history
PaperPlane walks back through your existing mail and links the messages by their headers, so the trees are complete from the first day rather than the second month.
- 3
Open the tree
Select any message and open the conversation tree. Widen the scope when the thread has moved elsewhere. Close the window and you are back in the list, where you left off.
// the app
It is a desktop app, and it looks like one
Native Windows, dark or light, English or Japanese.
Conversation tree
The whole conversation as a tree: received and sent on each node, branches where it split, and the scope selector for widening past a single thread.
Unified inbox
Every account in one list, with search running against the local cache rather than a provider's API.
// pricing
Priced like a tool, not a suite.
Less than what one hour of your time is worth.
Monthly
$9.99
/ month
Billed monthly. Cancel any time.
14-day free trial · no card required
YearlyTwo months free
$99
/ year
Billed once a year. Works out at $8.25 a month.
14-day free trial · no card required
The app is in final testing. Leave the tab open — this button goes live within days.
Both plans include
- Unlimited mail accounts
- Conversation tree with scope widening
- Gmail / Microsoft 365 OAuth, IMAP and SMTP
- Local cache and offline reading
- All updates while your subscription is active
- Windows 10 and Windows 11
Billing is handled by Paddle as merchant of record, so VAT and sales tax are calculated and included at checkout.
Cancel any time from the receipt email. 30-day refund policy.
// questions
Questions worth asking first
What makes this different from Outlook or Thunderbird?
They show a conversation as an indented list, or as a flat one. Neither tells you where the thread branched, which fork died, or that the mail with the changed subject line belongs to the same conversation. PaperPlane draws it as a tree, and lets you widen the scope until the whole conversation is on screen at once.
How is the tree built?
From the Message-Id, In-Reply-To and References headers that mail servers already attach to every message — the same data used to route replies. When a client has stripped them, PaperPlane falls back to matching on subject and participants, and marks bulk mail separately so a mass mailing never turns into a fake thread.
Which mail accounts can I connect?
Gmail and Microsoft 365 / Outlook.com through OAuth, iCloud and Yahoo through app passwords, and any other provider over standard IMAP and SMTP. Multiple accounts are merged into one unified inbox, and a tree can span them.
Does PaperPlane read my mail on a server?
No. PaperPlane is a desktop application. It talks to your mail provider directly from your own machine and caches messages in a local SQLite database. There is no PaperPlane server in the path of your mail, and your credentials are sealed with Windows DPAPI.
What happens to my mail if I stop paying?
Nothing. Your mail lives with your provider, exactly where it did before. PaperPlane stops fetching new mail when the subscription lapses, but nothing is deleted and you can go back to any other client at any time.
Which operating systems are supported?
Windows 10 and Windows 11. macOS and Linux are not supported today, and there is no dishonest 'coming soon' attached to that.
Who makes it?
dhq-boiler — an individual developer in Japan who also builds boiler's Graphics, STREAM DIRECTOR and JidoDebugger. PaperPlane is written in C# and WPF, and it is the tool its author needed first.