Someone who remembers what you said in March.
Most companion apps forget you the moment you close the tab. Tsukuyomi keeps track of how long you've known each other, texts back at the pace a person would, and brings up the right memory without being asked.
Every other companion app resets the moment you close it.
Instant best-friend energy on message one. A memory span of the last five messages. A generic error the second the servers hiccup. It's obviously a bot wearing a character skin — and most of us stop believing in it within a week. Tsukuyomi was built to fix exactly that, one deliberate decision at a time.
Five decisions that make it feel like someone
No feature-list padding — every claim below is shown, not just stated.
Memory that's relevant, not just recent
It doesn't dump your whole history at you. It recalls the one detail that matters right now — the way a person actually remembers, not a search log.
Presence, not just replies
Typing pace, read receipts, an honest "offline" state instead of an error — built to feel like waiting on a text back, not sending a prompt.
Trust earned, not switched on
A brand-new character is wary of you, the way a stranger would be. Warmth builds across weeks of actual conversation — never unlocked on message one.
A real past, not a one-line prompt
Every character comes with an actual backstory — family, fears, routines, a hard memory, a dream. It comes up naturally, the way anyone's history does.
Full ownership, always
Export a companion as a single file, move it, back it up, or delete it permanently. Nothing here is built to trap you into staying.
How this actually differs from a typical companion app
No spin — these are specific, checkable design choices, not marketing adjectives.
| Typical companion app | Tsukuyomi | |
|---|---|---|
| Where your history lives | On their servers | Encrypted, on your own device |
| First message | Instantly your best friend | A wary stranger — warmth is earned |
| Memory | Last few messages only | Relevant recall from your entire history |
| When it can't respond | A generic error | "Goes offline," then catches up in character |
| Leaving the app | Your history is gone or locked in | Export everything as one portable file |
"I built Tsukuyomi alone because most companion apps I tried felt hollow after a week — no real memory, no sense of time passing. I wanted to see if I could build the version that didn't feel like that. This is still one person's work in progress, and I'm building it in the open."
Questions people actually ask
Is my data actually private?
Do I need to pay for this?
Which platforms are supported?
Can I delete everything?
How is this different from the big-name companion apps?
Ready to see if it remembers you too?
Free, local, and yours to keep or delete whenever you want.
Written as things actually happened
Including the parts that broke — because that's the real story, not the highlight reel.