Post

Build XDBChain Apps

By XDBChain 5 min read

Build cool things on XDBChain! This list outlines a few ideas for applications. Feel free to add your own or take one here and run with it. As always, if you need help building anything with XDBChain, just email to developers@xdbchain.com.

Slack Bot

  • Report a stream of all XDBChain transactions to a channel.
  • Advanced: Allow people to send money/points/+1’s to other Slack team members /send @bob $5.

API Mashups

  • Twitter meets XDBChain: Tweet to send money or Twitter alerts
  • Many more possibilities

Graph of Horizon data

A relatively simple project that graphically displays information pulled from Horizon and could look up accounts and transactions. It would also be cool to see:

  • Tree of account creation. All accounts are created by other accounts, so you could show this tree of lineage.
  • Graph of ledger header info over time:
    • Transaction count
    • Operation count
    • Ledger close times
    • Fee pool

Federation Service

Implement a simple Federation server and setup a webpage where anyone can claim a name*yourdomain.com XDBChain address and associate their XDBChain account ID with it. The catch is your service will only federate for accounts that set their inflation destination to one provided by your domain.

You can also contribute to the federation server maintained by Stellar.

XDB to any email address

Allow anyone to send XDBs from their XDBChain client to any email address. They would simply enter something like <emailaddress>*domain.com and then they are able to send it XBDs. If the recipient doesn’t have a XBDChain account already one will be created for them and they will get an email alerting them that they have XDBs.

This would be a service hosted at domain.com that does the following:

  • Runs a federation server.
  • Will federate payment addresses with an email prefix like joe@xdbchain.com*domain.com.
  • If there is a federation request for an address you don’t know that starts with a valid email address:
    • Generate a key pair
    • Return the generated public key as the accountID
    • Watch the network to see if that account is created.
    • If the account is created, you send an email to the given email address with the private half of the keypair with links to a XDBChain client.

Advanced allow people to manage the XDBChain account you just created for them by sending emails to control@domain.com. This makes someone’s inbox a XDBChain client. For example: send 100 XDB to bob@gmail.com

Resource Paywall

Let’s say you have a public-facing service, perhaps for streaming or open wifi. You want to allow other people to use this service if they pay you small amounts. These payments could be used for spam prevention or to support your business. This is a job for the toll collector…

Toll Collector

A simple service that keeps track of any XDB sent to a toll address. The toll collector has a database of public keys and amounts of XDB it has sent to the toll address. It watches for payments to the toll address on the XDBChain network and adds them to this DB.

The toll collector service has one RPC or endpoint that you can call:

  • charge(publicKey, amount of XDB) returns
    • amount XDB charged
    • amount of XDB this key has left

Your app can publish its XDBChain toll address for payments. When someone tries to use your service, the server has them authenticate their public key and calls charge on the Toll Collector to decrements the consumer’s balance in the DB. You can send the consumer a message when their balance is zero.

Multisig Coordinator

A web application that facilitates creating multisig transactions. Typically you must coordinate between several parties to generate a transaction for an account protected by multisig. This site would make this process much easier and allow you to coordinate in cases where you don’t know the other party.

Ideally, the multisig coordinator includes the following features:

  • Associate an email address with your public key
  • Create a tx that you would like to be signed by multiple parties
  • Enter the public keys that you would like to sign the tx
  • If any of these keys have previously associated their email address, then they will be sent a message
  • When you come to the site you see a list of all pending transactions:
    • You can see the details of each transaction
    • You can see who initiated the transaction
    • You can see who else has signed the transaction
    • You can sign any that are waiting for you
  • Once a pending transaction is signed by enough people, it is submitted to the network
  • Once the transaction is submitted, all the signers are notified

Market Feed

Data feed for the distributed Exchange inside XDBChain. Something equivalent to the Poloniex API. This will be useful for apps as well as getting the XDBChain trade volume added to charting sites like CoinMarketCap

Quorum Monitor

A web page that shows the state of the network quorum graph. Ideally, the quorum monitor shows:

  • A live graph of how the network is connected
  • What servers are having issues
  • Any servers that disagree with the rest of the network
  • Perhaps a history of uptime for each validator

You should be able to view the quorum graph from the point of view of any given validator. You would probably need to run stellar-core to build the quorum monitor. You can get the data from the stellar-core logs and the /quorum command.

Advanced: Build a server that connects to stellar-core and monitors the externalized messages and the various validator broadcasts.

Libraries

Build a library in your favorite language:

  • C#
  • PHP
  • Haskell
  • Other languages

Or contribute to existing Stellar SDKs:

Product and Service Ideas We’ve Heard

  • Microsavings account for school, health, insurance
  • Microinsurance
  • P2P lending
  • Conditional cash transfers
  • Donation systems for nonprofits
  • Loyalty points programs
  • Community currencies
  • Time banks
  • Volunteer hour tracking
  • Anywhere ATM or human ATM mobile apps

Atomic cross-chain swap facilitator

  • End-user software that to facilitate atomic cross-chain swaps with various other cryptocurrencies.
  • A rendezvous service establishing a marketplace for cross-chain swaps.
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