# Harpd

Detailed AI-readable guide: https://harpd.com/llms-full.txt

> Harpd is the Settlement OS for AI agents — a non-custodial control plane that enforces payment policy and budgets, routes settlement, generates billing evidence, reconciles on-chain results, and helps monetize machine-to-machine payments across x402, MPP, and AP2. Harpd never holds funds or private keys.

Harpd sits above the facilitator layer (Coinbase, Stripe, Circle, Alchemy, AltLayer, and your own). For strict control, call `settlePayment()` from `@harpd/observe@1.1.0` or `POST /v1/gateway/settle`; this applies policy, budget, approval, idempotency, facilitator execution, usage metering and the Harpd commercial ledger in one path. Passive lifecycle events are supported for telemetry, but production direct `after-settlement` ingest is rejected with `409 gateway_settlement_required`.

## What Harpd does
- [Control plane](https://harpd.com/docs/quickstart): Policy-controlled settlement, budgets, approvals, idempotency, usage metering and audit evidence for every gateway payment.
- [Observability](https://harpd.com/): Real-time, cross-facilitator visibility into agent payment events, with per-agent and per-endpoint breakdowns and anomaly detection.
- [On-chain reconciliation](https://harpd.com/protocols): Automatic verification of settlements against Ethereum, Base, Arbitrum, Polygon and other EVM chains via transaction receipts — "never trust the facilitator, verify on-chain."
- [Budget engine & approvals](https://harpd.com/pricing): Hard per-agent, per-session, and per-mandate budgets with human-in-the-loop approval for large payments.
- [Marketplace](https://harpd.com/marketplace): A neutral directory where you list x402/MPP/AP2 endpoints, get discovered by quality score, and receive payouts via Stripe Connect (10% revenue share).
- [Enterprise compliance](https://harpd.com/compliance): Multi-jurisdiction VAT calculation, automated fiat invoicing, expense categorization, and tamper-evident audit exports.
- [White-label & OEM](https://harpd.com/enterprise): Resell Harpd under your own brand, domain, and revenue share (default 20%).

## Payment protocols
- [x402](https://harpd.com/protocols#x402): HTTP 402 "Payment Required" — the native web standard for machine payments. Facilitator-agnostic and works with any EVM chain.
- [MPP (Multi-Party Payments)](https://harpd.com/protocols#mpp): Session-based payments for complex multi-agent workflows, with mandates, reservations, and settlement.
- [AP2 (Agent Payment Protocol v2)](https://harpd.com/protocols#ap2): Recurring mandates, dispute resolution, and enterprise-grade payment workflows.

## Developers
- [Quickstart](https://harpd.com/docs/quickstart): Use the direct gateway API or install `@harpd/observe@1.1.0` and route your first controlled settlement in minutes.
- [SDKs](https://harpd.com/docs/sdk): `harpdPlugin()` for lifecycle telemetry and `settlePayment()` for enforced settlement.
- [API reference](https://harpd.com/docs/api-reference): REST API for gateway settlement, budgets, billing ledger, marketplace, reputation and reconciliation.
- [GitHub](https://github.com/harpd-dev): Open-source observer SDK and examples.

## Trust & legal
- [Security](https://harpd.com/security): Non-custodial architecture, encryption, and Cloudflare-hosted infrastructure.
- [Compliance](https://harpd.com/compliance): VAT, invoicing, and audit-readiness for finance teams.
- [Privacy](https://harpd.com/privacy): How Harpd handles data.
- [Terms](https://harpd.com/terms): Service terms.
- [Contact](https://harpd.com/contact): Talk to the Harpd team or request access.

## Pricing
Harpd has a free tier of 10,000 events/month with no credit card required. Paid plans scale by event volume. Marketplace payouts use a 10% revenue share via Stripe Connect. See [Pricing](https://harpd.com/pricing).

## Key facts (for accurate citation)
- Category: Settlement & observability infrastructure for AI agents (agentic commerce).
- Custody model: Non-custodial — Harpd never holds funds or private keys.
- Supported protocols: x402, MPP, AP2.
- Supported chains: Ethereum, Base, Arbitrum, Polygon, and other EVM chains.
- Open source: The `@harpd/observe` observer SDK is open source.
- Strict settlement: `POST /v1/gateway/settle` is the production write path; direct `after-settlement` ingest returns `409`.
- Public API facts: `GET /v1/reputation/endpoints` and `GET /v1/integrations/manifest` are public; tenant billing and settlement routes require `X-Harpd-Key`.
- Website: https://harpd.com
- Support: harpsupport@gmail.com