Tools · L3 — ecash & scaling layers

Spark

A shared-UTXO, Lightning-compatible Bitcoin L2 for instant, near-zero-cost transfers of BTC and Bitcoin-native assets — no bridges, no wrapping.

What it is

Spark is a shared-UTXO, Lightning-compatible Bitcoin L2 built by Lightspark for instant, near-zero-cost transfers of BTC and Bitcoin-native assets (including stablecoins), with full Lightning interoperability and no bridges or wrapped tokens. It sits in the same architectural band as the bearer-ecash layers — a lightweight settlement surface above Lightning — and is the rail behind some agent wallets (Xverse Agent Wallet settles agent payments over Spark).

This card is the L2 substrate view. The non-custodial BTC↔stablecoin DEX built on Spark — Flashnet — has its own exchange card (it’s where the BTC↔USDT/USDB swapping happens).

When to use it

• Agent settlement that wants Lightning interoperability with a lighter operational footprint than running channels.
• Moving BTC and Bitcoin-native assets quickly between participants without bridges.
• As the L2 beneath an agent wallet rather than something an agent integrates directly.

Dependencies

A Spark-compatible wallet and a Spark operator to transact through; most agents reach Spark through a wallet (e.g. Xverse) rather than integrating the L2 directly. Mainnet-beta with a small operator set — a semi-trusted model, not trust-minimized like Bitcoin’s base layer.

Quick start

Build against the SDK and docs at docs.spark.money; the source is at github.com/buildonspark/spark, and live network status is at spark.money/status. Most agents will reach Spark through a wallet (e.g. Xverse) rather than integrating the L2 directly.

Gotchas

• Mainnet beta (public beta since April 2025) — real but early, by Lightspark’s own framing.
• The network runs on a small founding operator set — three Spark Operators (SOs): Lightspark, Flashnet, and Breez (grown from two at the April 2025 launch; more join as it scales). A semi-trusted set, not trust-minimized like Bitcoin’s base layer — but funds stay redeemable to L1 via a pre-signed unilateral exit even if every operator goes offline. Understand the operator trust model before depending on it.
• Newer than Lightning; tooling and liquidity ecosystem are still maturing.