Stellar Hacks · Agents Track

Spending governance for autonomous AI agents on Stellar.

SpendGuard is a Soroban policy contract that sits between your agent and the x402 payment flow. Set daily caps, whitelist merchants, pause on demand — and every decision is enforced on-chain, not in a server you have to trust.

Live ContractConnecting…

Vault Balance

$0.00USDC

Daily Cap

$0.00

Max / Tx

$0.00

Network

Stellar testnet

Contract

What it does

Four guardrails, all enforced on the ledger.

shield

On-Chain Guardrails

Daily spending caps, per-transaction limits, and merchant allow-lists enforced by a Soroban contract — not by a server that can be bypassed.

bolt

x402 Native

Agents pay the HTTP-native x402 price signaled by the merchant. Settlement lands on Stellar through the OpenZeppelin Relayer facilitator.

lock

Emergency Kill Switch

Pause the contract from the dashboard and revoke all new authorizations instantly. In-flight transactions on the ledger remain final.

history_edu

Immutable Audit Log

Every settlement and every denial is derived directly from Horizon. No mutable backend store, no rewriteable history.

How a payment flows

x402 → SpendGuard → Stellar.

  1. 01

    Agent requests resource

    HTTP GET with no payment

  2. 02

    Merchant replies 402

    Signals price + asset

  3. 03

    SpendGuard pre-checks policy

    Budget, cap, whitelist, pause

  4. 04

    Soroban auth-entry signed

    Facilitator broadcasts

  5. 05

    Merchant returns resource

    Settlement final on Horizon

Ready to put your agent on a leash?

Walk through a live end-to-end flow on Stellar testnet — no wallet required.