Email walks from your inbox to your evening. Line the route with spam filters, out-of-office replies and one very important coffee machine.
Pick a tower from the shop (or press 1, 2, 3), then click a dashed slot beside the route to build it. Click a tower you have already built to upgrade it — two levels each — or sell it back for 60% of what you put in. Space sends the next wave, P pauses, Esc clears your selection. Nothing spawns until you send it, so take your time between waves.
Kills pay Focus, and so does surviving a wave. Every message that reaches the far edge costs Sanity — twenty points, and the boss takes six of them at once. Fifteen waves and the evening is yours.
Spam Filter — cheap, fast, single target. Build these first and build a lot of them.
Out of Office — hits softly but knocks mail backwards down the route, buying every other tower more time. Best placed near the end.
Coffee Machine — deals no damage at all. Everything in its circle fires faster. One good placement beats two more filters.
Urgent!! ASAP — fast, flimsy, arrives in crowds.
Sync (no agenda) — slow, enormous, absorbs everything you have.
LinkedIn Influencer — takes damage normally, but everything near it takes 30% less. Kill it first.
The Boss, 17:04 — arrives on waves 10 and 15 and costs six sanity if it gets through.
Inbox Defender takes the oldest joke in office work — that email is something you defend against rather than read — and makes it literal. Messages leave the inbox at the top left of the board and walk a fixed route across your week towards the bottom right, where your evening is waiting. Everything you build sits beside that route: a spam filter that shreds whatever comes past, an out-of-office reply that bounces a message back the way it came, and a coffee machine that makes its neighbours quicker without ever firing a shot.
The interesting decisions are all about geography. A coffee machine in a corner is wasted; the same machine placed where two straights and a turn meet doubles the value of four filters at once. An out-of-office reply near the finish line can push a tank all the way back through your whole defence. And the LinkedIn Influencer exists purely to punish players who spread their damage thin — while it lives, everything travelling with it shrugs off a third of your firepower.
It runs on canvas in a single browser tab, with no install, no account and no launcher. Fifteen waves, twenty sanity, and one very optimistic boss who thinks 17:04 is still working hours.
Is Inbox Defender free to play?
Yes. It runs in your browser, it costs nothing, and there is no account, download or launcher. Open the page and press a key.
How many waves does Inbox Defender have?
Fifteen. Waves only start when you send them, so you can build between them for as long as you like. The Boss arrives on wave 10 and again on wave 15, and costs six sanity if it gets through.
Which tower should I build first?
Spam Filters, and spread them along the whole route rather than clustering them at the start. Once you have four or five running, put a Coffee Machine where several of them fall inside its circle — it deals no damage itself but makes every neighbour fire faster, which is worth more than another filter.
How do I stop losing sanity?
Sanity is your health: you start with twenty and lose it whenever a message reaches the far edge. An Out of Office tower placed near the end of the route knocks mail backwards through your whole defence, which is the cheapest way to stop leaks. Kill LinkedIn Influencers first, because everything travelling near them takes 30% less damage.
Does Inbox Defender work on a phone?
Yes — the board, shop and log stack into one column and towers are placed by tapping a slot. Tiles are small on a narrow phone, so a tablet or desktop is more comfortable, but nothing is keyboard-only.
Is my progress saved?
Your best wave is stored in your own browser, so it survives a reload but does not follow you to another device. There are no accounts and nothing is uploaded.