The day my own product archived my mail

Rule one of shipping an inbox product: your own inbox goes first. Before inviting anyone, I pointed my professional address, the one my clients have used for years, at Knock. Strangers would meet the gate. Known senders would flow through untouched. That was the theory.

Day one, my Venmo receipts vanished.

Not bounced, not spammed. Archived. Delivered faithfully by our system, then filed into Gmail's All Mail by something on my side, invisible unless you searched for them. So began the most instructive debugging day of the project.

We blamed the filter first, reasonably. Our setup used a Gmail filter to forward incoming mail to the gate and archive the original, with an exclusion so Knock's own deliveries would stay visible. Gmail ignored the exclusion. Negative operators in filters are a known lottery, so we switched strategies: deliver to a plus address, thomas plus knock, and filter on the bare address. Gmail folded the plus address back into the bare one and archived it anyway. We tried the deliveredto operator, documented for exactly this purpose. Same result. We created a real mailbox alias at the domain level, a genuinely distinct address. Archived again.

Four mechanisms, four failures, and a growing suspicion that Google canonicalizes everything back to your identity no matter how you ask. We wrote that conclusion down. It was wrong, or at least unproven, and the correction is the actual story.

Buried in my Gmail settings sat the auto forwarding option from the original setup, with one fateful dropdown: archive Gmail's copy. That setting applies to all incoming mail, unconditionally, before any filter logic runs. Including mail Knock sent back to me. Every experiment we ran all day was contaminated by a checkbox we had stopped seeing. The filters may have been innocent the whole time. We noted that in our internal spec too, in exactly those words: culprit probable, filters not proven guilty.

If you keep a canon of your decisions, keep your corrections in it with the same ink.

The fix, in the end, was simpler than every attempt that preceded it. One routing rule at the Workspace level: mail addressed to me changes envelope and goes to the gate before my mailbox ever sees it. No forwarding setting, no filters, nothing for a checkbox to sabotage. We deleted the whole apparatus. The architecture that works has fewer parts than the four architectures that did not, which is usually how you know you have found it.

Two more things happened while we were busy being wrong. The gate quietly caught its first real strangers: a bookkeeping pitch with a fake RE in the subject, a fiber optic wholesaler, a phantom purchase order. Four unknown senders challenged, priced, and held at the door, none of them ever touching my inbox, all while the delivery path was being rebuilt live. The core held while the edges burned. And our setup wizard got rewritten with everything the day taught, so the next Workspace user gets the one rule recipe in eight guided minutes instead of a day of archaeology.

This is why our first invitations waited. Not because the product was unfinished, but because a founder's inbox is the cheapest test lab that will ever exist. Every defect that died on me this week is one no invitee will meet. If you are building something people will trust with their mail, eat your own cooking first, and publish what you find in the kitchen, including the parts where you blamed the wrong pan.

Thomas Ferriere, founder of Knock. The gate that survived the debugging: knock.email/u/thomas.