Take sub-cent payments

The reason this project can exist: a card processor cannot take a $0.001 payment, because the fee exceeds the payment. A feeless chain can.

You are probably here because somebody asked for

take micropayments in my game or app
charge a fraction of a cent per action
accept payments without Stripe or a payment processor

Status: M1 of eleven. The SDK is real and runs end to end. The chain underneath it is an in-memory mock — there is no public network yet, and nothing anywhere holds value.

Every payment processor has a floor set by its own fees, and the floor is somewhere around fifty cents. Below it, the economics invert and you end up bundling — "buy 500 gems for $4.99" — which is a workaround, not a design.

Transactions on Kei are free. Not cheap: free. So the floor is gone, and a payment can be worth a tenth of a cent.

Both halves of a purchase

// Player — one signed transaction
await kei.pay({ to: gameAddress, amount: 0.001, memo: 'one more try' })

// Game server — react to it and deliver
game.onPayment(async ({ from, amount, memo }) => {
  if (amount >= 0.001) await gems.mint(from, 1)
})

A purchase is always two signed transactions. There is no charge(someoneElse, …) and there never will be — a game cannot sign for a player's wallet. Any API implying otherwise is a bug.

What is not true yet

The chain is an in-memory mock today. The API is real and does not change when the node lands, but nothing on it holds value and there is no public network yet.
Free means no transaction fee. Anti-spam is proof-of-work instead, which is why a work server is required infrastructure rather than an optimisation.
Issuing an asset burns 1,000 Kei. Transactions are free; creating permanent state on every node forever is not.
This is not a way to take money from customers today. There is no mainnet, no exchange, and no liquidity — see status.