Sequence

Ledger Infrastructure for Modern Applications

Sequence is a system of record for managing balances. It lets software teams focus on shipping and scaling their product instead of building and maintaining ledger infrastructure.

What can you build on Sequence?

Sequence is a system of record for managing balances. It lets software teams focus on shipping and scaling their product instead of building and maintaining ledger infrastructure.

A Mobile Wallet

Store and Transact user balances.

See Code Example

A Ride-Sharing Service

Manage consumer and driver balances.

See Code Example

A Lending Platform

Issue and service loans.

See Code Example

A Crypto Exchange

Securely custody client funds.

See Code Example

A better model for managing balances

Assets in accounts...

Balances in Sequence are represented by token-like objects called assets. Assets are created, transferred, and retired. To ensure atomicity, a single transaction can include multiple actions involving any number of assets and accounts.

...Controlled by keys in enclaves

Cryptographic keys, which create and control assets and accounts, are managed in secure enclaves. Key access can be distributed across users, services, and organizations so multiple entities can transact on the same ledger with “least authority.”

Built for developers

Create Keys

Create Accounts

Create Assets

Transact

Query

What Are Keys?

Transactions in the ledger are authenticated by cryptographic keys. To create a key, provide an alias (a unique identifier).

1Key key = new Key.Builder()
2            .setAlias("my_key")
3            .create(ledger);

Java•Node•Ruby

View Documentation

Built for developers

Create Keys

What Are Keys?

Transactions in the ledger are authenticated by cryptographic keys. To create a key, provide an alias (a unique identifier).

1Key key = new Key.Builder()
2            .setAlias("my_key")
3            .create(ledger);

Java•Node•Ruby

Create Accounts

What Are Accounts?

Accounts represent entities in the ledger and can hold balances of many assets. To create an account, provide an alias (a unique identifier) and one or more keys. Here we create an account for Alice.

1Account alice = new Account.Builder()
2            .setAlias("alice")
3            .addKey(key)
4            .create(ledger);

Java•Node•Ruby

Create Assets

What Are Assets?

Assets represent different types of balances in the ledger. To create an asset, provide an alias (a unique identifier) and one or more keys. Here we create a USD asset.

1Asset usd = new Asset.Builder()
2            .setAlias("usd")
3            .addKey(key)
4            .create(ledger);

Java•Node•Ruby

Transact

What Are Transactions?

Transactions are atomic ledger updates that issue, transfer, and/or retire assets in the ledger. A transaction is comprised of one or more actions. Here is a transfer of USD from Alice to Bob.

1Transaction tx = new Transaction.Builder()
2            .addAction(new Transaction.Builder.Action.Transfer()
3              .setAssetAlias("usd")
4              .setAmount(10)
5              .setSourceAccountAlias("alice")
6              .setDestinationAccountAlias("bob")
7            ).transact(ledger);

Java•Node•Ruby

Query

What Are Queries?

Data structures in Sequence are represented as key-value JSON objects. To retrieve data, you perform a query with optional parameters. By default, each query returns a time-ordered list of objects beginning with the most recent. Here’s a query for the amount of USD in Alice's account.

1Balance.ItemIterable balances = new Balance.QueryBuilder()
2            .setFilter("asset_alias=$1 AND account_alias=$2")
3            .addFilterParameter("usd")
4            .addFilterParameter("alice")
5            .addSumByField("asset_alias")
6            .getIterable(ledger);
7          for (Balance balance : balances) {
8            ...
9          }