There are three ways to accomplish micropayments using 21.Let's go through these in turn after going through some preliminaries.To understand the micropayment methods supported by 21, we first start with the concept of your 21.co buffer and your wallet/Blockchain balance.The reason these are separate is that directly sending and receiving bitcoin is slow under the best of circumstances, and not fast enough to permit rapid acquisition of bitcoin for programming purposes.As such, we have implemented something we call buffering to speed up the process.You can buy and sell digital goods with other 21 users within the 21 Network using your 21.co buffer, and then flush to your wallet when ready.This process of doing 21 flush will increment your wallet/blockchain balance.Your 21.co buffer: This is your buffer at 21.co.It is constantly incremented by the APIs you run in the background after your first run of 21 sell --all.Your 21.co buffer can also be increased by selling digital goods and services to others within the 21 Network.

You can flush bitcoin from your 21.co buffer to your wallet with 21 flush.Importantly, only you can flush, buy, or earn to your 21.co buffer - every action on this buffer must be signed by your wallet.Your blockchain/wallet balance: This is the balance in your 21 wallet on your local device.It is "local" in the sense that the private keys for the wallet are local to your laptop, 21 Bitcoin Computer, or other device.Your wallet's balance is visible on the blockchain and can be viewed with any block explorer.You can increase your blockchain/wallet balance by doing 21 flush, or by sending bitcoin directly to a wallet address.As background, since the beginning of the World Wide Web there have been many attempts to implement micropayments.In fact, the HTTP specification includes an error code which is typically not used: "Error 402, Payment Required".We have implemented this error code in all three of our micropayments systems; as you go through the code samples, you will see it recur repeatedly as the initial challenge that a server issues when a client attempts to access a bitcoin-payable, HTTP-accessible resource.

How the client responds to this challenge differs depending on which of the three 21 micropayments systems you use.With on-chain transactions, the client creates and broadcasts a new transaction for every challenge issued by the server With off-chain transactions (BitTransfers), the client and server pay each other from their 21.co buffer, and then flush to the blockchain when done With micropayment channels, the customer temporarily locks up some of their satoshis on the blockchain and can then release them one satoshi at a time to a merchant by creating a special transaction the merchant can broadcast to the blockchain before the customer's lock expires.This allows the customer to make repeated payments as low as a single satoshi for the transaction fee cost of just two on-chain transactions.Each of these methods are described in more detail below.Before you can do an on-chain transaction at 21, you need bitcoin in your machine wallet.

You can do this by either (a) sending bitcoin to an address in your wallet or by (b) using 21 flush to flush bitcoin to a blockchain address controlled by your wallet.bitcoin conference mexicoOnce you have some bitcoin, suppose you want to buy a bitcoin-payable API with an on-chain transaction.bitcoin ransom paymentHere is the sequence of events that occur for an on-chain transaction: This process is (relatively) simple to understand, but highly inefficient as it will send one transaction to the blockchain for every API request.ethereum with credit cardIn the two1 library, we have developed a function which handles the mechanics of this process; here is how to call it within code: = = () = = .(=)armory bitcoin install

The general concept behind off-chain transactions is to avoid the inefficiency of writing to the blockchain until requested by the user.bitcoin 2014 forbesBefore you can execute an off-chain transaction in the 21 system, you need a bitcoin buffer at 21.co.ethereum not a store of valueYou can get some by selling a digital good to someone for bitcoin.bitcoin suisse twitterOnce you have some bitcoin in your 21.co buffer, here is the sequence of events that happen when you execute an off-chain transaction to buy an API call from another 21 user: These mechanistic details are taken care of for you on both the client and server sides with the two1 library.bitcoin lavoro

Here is how to execute an off-chain transaction (also known as a BitTransfer): = = () = = .(=)mit bitcoin online bezahlenWhile off-chain transactions are fast, they only interface with the Bitcoin network at the very end (when you are doing a 21 flush) and require some trust in a centralized actor (namely us!).While we do think we are reasonably trustworthy people, we also support micropayment channels, which have many of the advantages of both off-chain transactions (in terms of performance) and on-chain transactions (in terms of having the decentralized and low-trust security of blockchain transactions).One important note: our implementation of micropayment channels benefits from the fact that every client has bitcoin.As such, setting up the initial micropayment channel deposit is easy.Here's how you would execute a micropayment channels payment: = = () = = .(=)