claude-dev-suite Spark (Lightspark)
Spark is an open-source L2 by Lightspark (David Marcus, ex-PayPal / ex-Facebook) launched April 2025. Builds on statechain concepts with FROST threshold signing and a leaf-based structure for partial transfers.
Architecture
Core components:
- Spark Operators (SOs): collective threshold signers, FROST k-of-n.
- Leaves: terminal off-chain UTXOs owned by users; each has a relative-timelock exit transaction.
- Trees: hierarchical structure supporting partial-balance transfers.
Leaves
Each Spark leaf is:
- An off-chain UTXO with FROST-aggregated multisig.
- A relative-timelock unilateral exit tx that anyone can broadcast after CSV expiry to extract the leaf on chain.
- Transferable off-chain via SO-coordinated protocol.
Security model
1-of-n trust on Spark Operator collective:
- As long as one operator behaves honestly, user funds remain secure.
- FROST threshold signing means no single SO controls the keys.
- Exit guarantee: even if all SOs collude/disappear, user can always exit via timelocked path.
Currently launched with 2 operators (Lightspark + Flashnet); planned expansion to diverse jurisdictions.
Lightning compatibility
Spark integrates with Lightning:
- Spark balance can be used to pay Lightning invoices.
- Lightning balance can flow into Spark.
- Bridges via Lightspark's Lightning infrastructure.
API
Lightspark provides SDKs:
- TypeScript / JavaScript.
- Go.
- Python.
- iOS / Android (Swift / Kotlin).
const wallet = new SparkWallet({ apiKey });
await wallet.deposit({ amount: 10000 });
await wallet.send({ to: "user@spark.money", amount: 5000 });
await wallet.payLightningInvoice("lnbc100u...");
Compared to Ark
| Aspect | Spark | Ark |
|---|---|---|
| Operator | k-of-n FROST | 1 ASP per round |
| Architecture | Leaf trees | VTXO trees |
| Round-based | Continuous | Periodic rounds |
| Status | Live beta | ARKADE live beta |
| Lightning integration | Native | Optional / future |
| Stablecoins / tokens | Yes (planned) | Yes (Arkade Assets) |
Use cases
- Stablecoin / token payments on Bitcoin (multi-asset).
- Mobile-first wallets with no channel-management UX.
- Enterprise: integrated with Lightspark's existing LN infrastructure.
Status & roadmap (2026 Q2)
- Beta active with 2 operators.
- Q2 2026 roadmap: expanded operator set, more jurisdictions, deeper Lightning integration, asset support.
- UMA (Universal Money Address) integration alongside Spark for cross-currency payments.
Limitations
- k-of-n trust: although FROST minimizes single-operator compromise, you still trust the operator collective.
- Lightning bridging: requires LSP-like layer; integration costs apply.
- Newer: less battle-tested than Lightning.