Crate breez_sdk_core

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§Breez SDK

The Breez SDK enables mobile developers to integrate Lightning and bitcoin payments into their apps with a very shallow learning curve. The use cases are endless – from social apps that want to integrate tipping between users to content-creation apps interested in adding bitcoin monetization. Crucially, this SDK is an end-to-end, non-custodial, drop-in solution powered by Greenlight, a built-in LSP, on-chain interoperability, third-party fiat on-ramps, and other services users and operators need.

The Breez SDK provides the following services:

  • Sending payments (via various protocols such as: bolt11, keysend, lnurl-pay, lightning address, etc.)
  • Receiving payments (via various protocols such as: bolt11, lnurl-withdraw, etc.)
  • Fetching node status (e.g. balance, max allow to pay, max allow to receive, on-chain balance, etc.)
  • Connecting to a new or existing node.

§Getting Started

First, make sure you have your API Key and Invite Code ready (see API Key and Invite Code section below).

The following code initialize the SDK and make it ready to be used:

ⓘ
let mnemonic = Mnemonic::generate_in(Language::English, 12)?;
let seed = mnemonic.to_seed("");
let invite_code = Some("...".into());

let mut config = BreezServices::default_config(
    EnvironmentType::Production,
    "your API key".into(),
    breez_sdk_core::NodeConfig::Greenlight {
        config: GreenlightNodeConfig { partner_credentials: None, invite_code },
    },
);

// Customize the config object according to your needs
config.working_dir = "path to an existing directory".into();

// Connect to the Breez SDK make it ready for use
let sdk = BreezServices::connect(
   config,
   seed.to_vec(),        
   Box::new(AppEventListener {}),
)
.await?;

We can now receive payments

ⓘ
let invoice = sdk.receive_payment(3000, "Invoice for 3000 sats".into()).await?;

or make payments

ⓘ
let bolt11 = "...";
sdk.send_payment(bolt11.into(), Some(3000)).await?;

At any point we can fetch our balance from the Greenlight node

ⓘ
if let Some(node_state) = sdk.node_info()? {
    let balance_ln = node_state.channels_balance_msat;
    let balance_onchain = node_state.onchain_balance_msat;
}

or fetch other useful infos, like the current mempool RecommendedFees

ⓘ
let fees: RecommendedFees = sdk.recommended_fees().await?;

These different types of operations are described below in more detail.

§A. Initializing the SDK

There are two simple steps necessary to initialize the SDK:

  1. BreezServices::default_config to construct the sdk configuration
  2. BreezServices::connect to connect to your node and start all required Breez SDK services

The first step takes the EnvironmentType and NodeConfig as arguments. Although you can create your own config from scratch it is recommended to use the BreezServices::default_config method and customize it according to your needs. Once the NodeConfig is created it is passed to the BreezServices::connect method along with the seed and and implementation of EventListener which is used to notify the caller of SDK events.

Now your SDK is ready to be used.

§B. Sending and receiving Lightning payments

Supported BOLT11 operations are

§C. Receiving an on-chain transaction (swap-in)

§D. Sending to an on-chain address (swap-out)

§E. Using LNURL

  1. parse the LNURL endpoint URL to get the workflow parameters.
  2. After getting the user input or confirmation, complete the workflow with BreezServices::lnurl_pay or BreezServices::lnurl_withdraw.

§F. Supporting fiat currencies

§G. Connecting to an LSP

§H. Utilities

Use parse to parse generic input. The input can come from the user, from a clicked link or from a QR code. The resulting InputType will tell you what the input is and how to treat it, as well as present relevant payload data in a structured form.

§Bindings

  • C#
  • Dart
  • Go
  • Kotlin
  • Python
  • React-Native
  • Swift

§API Key and Invite Code

You will need an API Key to use the SDK, as well as an Invite Code when you create a new node.

To get both of them, please contact Breez via email at contact@breez.technology or at https://breez.technology/#contact-us-form

§Support

Join this telegram group.

Modules§

Macros§

  • ensure_sdk
  • with_connection_retry
    Executes the given grpc call function. If an error is returned that indicates the connection broke, the call is tried again.

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