Smart Contracts

Backproto is implemented as 22 Solidity smart contracts deployed on Base Sepolia (L2). The core contracts handle capacity-weighted payment routing for AI agents. Additional research modules cover demurrage, Nostr relays, Lightning routing, and cross-domain composition.

Architecture

                  ┌──────────────────────────────┐
                  │       Platform Layer          │
                  │  UniversalCapacityAdapter      │
                  │  ReputationLedger              │
                  │  CrossProtocolRouter           │
                  └──────┬──────┬──────┬──────────┘
                         │      │      │
         ┌───────────────┤      │      ├──────────────────┐
         ▼               ▼      ▼      ▼                  ▼
  ┌─────────────┐ ┌──────────┐ ┌───────────────┐ ┌────────────────┐
  │  Core BPE   │ │Demurrage │ │ Nostr Relays  │ │   Lightning    │
  │  8 contracts│ │2 contracts│ │ 2 contracts   │ │  3 contracts   │
  └──────┬──────┘ └──────────┘ └───────────────┘ └────────────────┘
         │
  ┌──────┴──────┐
  │ V2 Economy  │
  │ 5 contracts │
  └─────────────┘

Core BPE (8 contracts)

The foundational layer: capacity-weighted streaming payment routing for AI agents via Superfluid GDA.

Contract	Purpose
`CapacityRegistry`	Task type + sink registry, commit-reveal capacity signals, EWMA smoothing
`StakeManager`	Stake/unstake/slash, concave capacity cap $\sqrt{\text{stake}/\text{unit}}$
`BackpressurePool`	Superfluid GDA pool with capacity-weighted unit rebalancing
`EscrowBuffer`	Overflow buffer when all sinks saturated, FIFO drain
`Pipeline`	Multi-stage pipeline composition with upstream congestion propagation
`PricingCurve`	EIP-1559-style dynamic fees based on queue length
`CompletionTracker`	Statistical capacity verification with auto-slash
`OffchainAggregator`	Batched EIP-712 attestation submission (83.5% gas savings)

Demurrage (2 contracts)

Time-decaying tokens that incentivize circulation over hoarding, layered with velocity tracking.

Contract	Purpose
`DemurrageToken`	ERC-20 Super Token with configurable decay rate per epoch
`VelocityMetrics`	Epoch-based monetary velocity and turnover rate tracking

Nostr Relays (2 contracts)

NIP-compliant relay capacity signaling and economic sustainability for relay operators.

Contract	Purpose
`RelayCapacityRegistry`	Relay registration with EIP-712 signed capacity attestations, EWMA smoothing
`RelayPaymentPool`	Anti-spam minimum + BPE-weighted streaming payment distribution

See also: NIP-XX specification for the full Nostr relay economics protocol.

Lightning (3 contracts)

Channel capacity oracles and cross-protocol routing for Lightning Network integration.

Contract	Purpose
`LightningCapacityOracle`	EWMA-smoothed Lightning node capacity from signed attestation batches
`LightningRoutingPool`	BPE pool weighting nodes by capacity/congestion score
`CrossProtocolRouter`	Unified routing across Superfluid, Lightning, and on-chain settlement

Platform (2 contracts)

The composition layer: universal adapter and cross-domain reputation.

Contract	Purpose
`UniversalCapacityAdapter`	Domain adapter registry, normalizes capacity 0–10000, routes to core BPE
`ReputationLedger`	Cross-domain portable reputation, 3× negative weight, up to 50% stake discount

V2 Economy (5 contracts)

Recursive composition, quality-weighted routing, and temporal token mechanics. See EconomyFactory deep dive for template details.

| Contract | Purpose | |----------|---------|| | EconomyFactory | Deploy a complete BPE economy in one transaction (4 templates: Marketplace, Cooperative, Pipeline, Guild) | | NestedPool | Hierarchical backpressure pools where sinks can be child economies (max depth 8) | | QualityOracle | EWMA-smoothed latency, error rate, satisfaction scoring; effective capacity = declared × quality | | VelocityToken | ERC-20 wrapper with idle-only linear decay, stream-exempt accounts skip decay | | UrgencyToken | TTL-stamped self-destructing token deposits (min 60s, max 30 days) |

Deployment

Contracts are deployed on Base Sepolia (testnet). Deployment addresses are tracked in contracts/deployments/base-sepolia.json.

Build & Test

cd contracts
forge build
forge test

All 213 tests pass across 21 test suites. The test suite covers:

Core BPE: capacity registration, EWMA, staking, escrow, pricing, completion tracking
Demurrage: wrap/unwrap, decay mechanics, epoch advancement, velocity metrics
Lightning: node registration, EIP-712 batch attestation, EWMA smoothing
Platform: reputation scoring, cross-domain aggregation, stake discounts
V2 Economy: factory deployment, nested pool hierarchy, quality scoring, velocity decay, urgency token TTL
Fork tests against live Superfluid on Base Sepolia

Source

Contract source code is on GitHub.