What is KŌINImemo?
A free app that writes permanent, structured memos to any wallet address on eight chains — Ethereum, Base, Arbitrum, Optimism, Polygon, BNB Chain, Avalanche and Solana. Each memo carries auto-filled machine fields (time, sender, recipient, chain), a category, optional reference fields, and your notes.
What does it cost?
The app is free and we charge nothing — no fees, no subscriptions, no in-app purchases. Each memo costs the network's own gas fee, paid from your wallet directly to the network. On most supported chains that is a fraction of a cent; on Ethereum mainnet it is substantially more, and the app shows you the estimate before you sign.
Does KŌINImemo ever move my funds?
No. Never. The app has no ability to receive or forward value — the on-chain mechanism is non-payable by design. Your wallet signs a memo transaction; nothing else.
How does the recipient see a memo?
They open KŌINImemo and connect (or just look up) their address — the inbox shows memos from all eight chains. Memos are also visible on any block explorer. There are no push notifications; a memo is a permanent record, not a chat ping.
Can a memo be edited or deleted?
No. Memos live on public blockchains and are permanent. The app can hide memos from your view, block senders, and filter content — but the underlying record is forever. Think before you write; the app reminds you too.
How does encryption work?
Notes (only the notes — categories, references and addresses stay public) can be encrypted on your device. For memos to yourself, the key is derived from your wallet's signature: reconnect the same wallet and the notes decrypt again, even years later. For memos to someone else, you choose a passphrase and share it with them off-chain. If a passphrase is lost, the notes are unrecoverable — by design, and by mathematics.
Which wallets work?
Any WalletConnect-compatible EVM wallet (MetaMask, Rabby, Coinbase Wallet, Trust Wallet and others), and Solana wallets through Mobile Wallet Adapter (Phantom, Solflare, Backpack).
I see an offensive memo. What can I do?
Open the memo and use Report (sends us the details), Block sender (hides everything from that address), or Hide (removes that memo from your view). Blockchain data can't be deleted, but your app shows only what you want to see.
Email support@koini.io — include your app version (Settings) and, if it concerns a specific memo, the tx hash and chain. We aim to respond within two business days.