SCF Build Award — $150,000

Executive Summary

REAPP is an open-source Stellar-native agentic payment rail — the missing infrastructure layer connecting Google AP2 authorization, x402 HTTP settlement, and Soroban policy enforcement into a composable SDK.

The Problem in One Sentence

AI agents can currently act on behalf of users — but they cannot pay on behalf of users without either holding private keys (custodial risk) or requiring human approval for every transaction (defeating the point of automation).

REAPP solves this with a three-component architecture: AP2 mandates express what the agent is allowed to spend and where, Soroban smart accounts enforce those limits on-chain without custody, and x402 on Stellar executes settlement in 2–5 seconds at $0.00001 per transaction.

What REAPP Is

An open-source Stellar-native SDK that enables AI agents to make bounded, auditable USDC payments without holding user private keys. Three open standards composed into a developer-first package: Google AP2 for authorization, x402 for HTTP-native settlement, Soroban for on-chain policy enforcement.

The implementation is adapter-first by design — all AP2-specific logic lives behind a versioned interface that can be swapped as the spec evolves or if a competing standard wins the agentic payments market.

The Four-Component Gap REAPP Fills
No existing project connects AP2 authorization, x402 settlement, Soroban enforcement, and Stellar's micropayment economics. This is not marketing — it is accurate as of March 2026.

The Honest Context

The agentic payments standard war is not resolved. Google AP2 launched September 2025 with 60+ institutional partners. OpenAI and Stripe launched ACP in February 2026 targeting traditional payment rails — no blockchain path. REAPP bets on AP2. The adapter-first architecture is the hedge.

The team is two engineers and 800 hours over five months. The timeline is tight. There is no formal smart contract audit in the budget. These are acknowledged tradeoffs, not oversights. The proposal's strengths — architecture clarity, the genuine ecosystem gap, Alex Astrum's AP2 insider knowledge, Stellar fit — are real and durable regardless of how the standards war resolves.

Competitive Position

Competitive Landscape
Coinbase AgentKit, Skyfire, and Nevermined are EVM-first with custodial models. x402stellar is a payment rail without an authorization layer. REAP Protocol targets EVM testnets with a different scope. No competitor occupies the AP2 + Soroban + x402 + Stellar quadrant.
ProjectAP2StellarNon-custodialx402Gap
Coinbase AgentKitEVM only, custodial model
SkyfirePartialEVM (Base), no Stellar
NeverminedNo Soroban, no AP2
x402stellarPayment rail only — no mandate layer
REAP ProtocolPartialPartialEVM testnets, different scope
REAPP

The Team

Alex Astrum
CTO · Developer Relations
Google Antigravity
  • Built ADK tooling from inside Google
  • Owns SDK architecture, CLI, docs, DX
  • AP2 insider knowledge — strongest asset
  • Direct access to AP2 spec authors
Owns: SDK packages · CLI · AP2 validator · documentation
Drew Raines
Lead Developer
Independent — Soroban / x402
  • Leads Soroban contracts and reference agents
  • x402stellar integration experience
  • Agentic systems architecture
  • TypeScript and Rust development
Owns: MandateRegistry contract · x402 glue · reference agents
Max Shama
Product & Ecosystem
AgenTools Labs · NEAR NDC alum
  • Governance at NEAR NDC ($21M+ fund)
  • Milestone execution and coordination
  • Early adoption and partnerships
  • Community builder program
Owns: External integrations · milestone tracking · community

Stellar Ecosystem Value

REAPP Ecosystem Value Chain
REAPP is upstream infrastructure. Every agentic payment through the SDK generates USDC volume, Soroban contract usage, and developer adoption on Stellar. x402stellar adoption grows as a direct dependency.
New USDC transaction flow
Every agent.fetch() call that crosses a 402 endpoint generates a Stellar USDC transaction. Volume scales with agent adoption.
New Soroban contract pattern
MandateRegistry establishes a reusable pattern for scoped agent authorization on Soroban — composable by any project.
Developer onramp
Sub-10-minute quickstart from zero to first agentic payment on Stellar testnet. Reduces time-to-first-transaction for agentic developers.
x402stellar upstream adoption
REAPP directly drives usage of x402stellar's four packages. Upstream ecosystem benefits from every REAPP integration.
Open-source MIT/Apache 2.0
All contracts, SDK, and CLI are open-source. No token, no protocol fee, no vendor lock-in. Fork it, extend it, deploy your own.
Prior art validation
All x402stellar and AP2 integration surfaces evaluated against current public documentation before submission. No unvalidated assumptions.