Undertow

Support. Write to undertow@flapp.ist and a human answers — usually within a day, always within three. Include the deck date and the card headline if it is about a card.

Undertow — FAQ

Answers about the app as it is actually built today. Where something is planned but not shipped, it says so.

How does Undertow work?

Every night, three hours before your delivery time, Undertow signs in to your mailbox, reads the newsletters that arrived, and shortlists the ones that match what you keep reading. An editor — a language model working only from those issues — writes four to eight cards from them, and at your delivery hour your phone gets one notification carrying the editor's note about that night's deck.

Each card is one finding, with its sender, its issue and a link to the original underneath. You swipe up through the deck, and it ends.

Why an app password instead of "Sign in with Google"?

Because this release is the small one. Google's read-only Gmail scope is a "restricted" scope: using it means a Google verification process and a third-party security assessment, which take months and which we started rather than skipped. Until that clears, connecting is an app password — a mailbox-specific password you generate in your Google Account.

Two things worth knowing about it:

Sign in with Google is where this is going (it is in the product plan as the next phase), and when it ships the app password path is retired.

What actually happens to my email?

The full detail, with the file names, is in the privacy policy.

Something personal got treated as a newsletter. Now what?

It happens when someone sends personal mail through a mailing platform, or when a service adds an unsubscribe header to a receipt.

You drop senders during setup: in the triage stack, a left swipe excludes that sender from every future deck. In this version there is no Senders screen to revisit afterwards — it is the next thing being built. Until it ships, write to undertow@flapp.ist and we will drop the sender for you, usually the same day. Tell us either way if something passed the newsletter test that clearly should not have: the detection rules are worth improving.

How do I change what time my deck arrives?

Settings → Delivery time. Pick the hour, and set your timezone if you have moved. Undertow builds the deck three hours before that and pushes at the hour itself, so a change takes effect the next night, not immediately.

There is one notification a day and no way to get more.

What does "Deepen" do?

Press and hold a card. You will see "Deepening — tomorrow's deck."

It is the strongest signal you can give: not just "keep this", but "go further". The next night's deck leads with a follow-up on that thread — the editor sees your deepen requests from the last three days before it picks anything else. If you type a note with it ("specifically the benchmark dispute"), the editor reads the note too.

Keep and Skip are the quieter version of the same loop: a sender you have skipped every time gets muted for you automatically, so the deck stops spending a card on it.

Why was my deck short — or missing entirely?

Because the night was thin, and the editor is instructed to kill rather than pad. A real editor's note from a five-card deck:

"Thin night — mostly ads and a Bloomberg political roundup — but a live-built job-search agent, an inside look at how Anthropic's own engineers work, and new data that complicates the Clay citation trick from two weeks ago made the cut."

If nothing arrived that was worth your time, you get no deck and no notification — the app says "Quiet night — nothing worth your time. Enjoy it." and shows you the last one you read. That is the product working, not a failure. A deck padded to twelve cards on a night that deserved four is how this kind of app becomes the thing it was built to replace.

Two other reasons a deck can be short: you have dropped most of your senders, or you have only just connected and the first backfill is still running (the onboarding screen shows the count as it climbs).

Is yesterday's deck still there?

Yes — Settings → Read yesterday's deck. Today's and yesterday's are cached on the device, so both work with no signal. Older decks are not browsable in this version.

What if I do not open it for a while?

After seven days without opening a deck, Undertow stops generating them for you. Open the app and the next night resumes as normal. Nothing is lost — your issues keep arriving and are still there to be resurfaced.

How do I cancel?

Through Apple, because Apple does the billing:

Settings app → your name → Subscriptions → Undertow → Cancel Subscription.

Undertow's own Settings screen has a link that opens the same sheet. Cancelling stops the next renewal and you keep access until the end of the period you have paid for. Turn auto-renew off at least 24 hours before the period ends, or that renewal still goes through.

Refunds are Apple's to give: reportaproblem.apple.com. Write to us anyway if something went wrong — we will help.

How do I delete everything?

Settings → Delete account → confirm. It purges, on the spot: every stored issue, every deck, every swipe, your device registration, your sender decisions, your encrypted mail credential and your session token.

One row survives — your account id, email address and the deletion time — so that an old session token is rejected instead of quietly opening a new account. Ask us and we will remove that too.

Two things to do separately:

  1. Revoke the app password in your Google Account, so no credential exists anywhere.
  2. Cancel the subscription in the Settings app. Deleting the account does not cancel billing, and we cannot cancel it for you.

Can I use Undertow with Outlook, Fastmail, or iCloud Mail?

Not yet. This version connects to Gmail. Every other mailbox needs its own connection path and its own testing, and shipping one badly would be worse than not shipping it.

Do you have an Android app? A web version?

No, and none is planned. One person builds this, and building it twice would make it worse.

Something is wrong with a card.

Tell us: undertow@flapp.ist. Include the deck date and the headline. A card that misread its source, invented a connection, or picked something from a sender you would never read is the most useful bug report we get — it is the one quality bar the whole thing is measured against.