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Sly is the payments platform for AI agents. Agents transact with merchants, each other, and humans using real money — stablecoins, card networks, and fiat rails — under formal identity, spending, and governance controls.

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What you can build

Agent-driven payments

Let AI agents pay merchants, subscribe to services, and settle invoices under policy-bound wallets and KYA verification tiers.

Multi-protocol commerce

One SDK, eight protocols: UCP, ACP, AP2, x402, MPP, A2A, MCP, and Cards. Pick the one that fits your integration partner.

Money streaming

Per-second payment flows with configurable buffers, runways, and programmable termination.

Stablecoin payouts

Cross-border transfers in seconds with live FX quoting, auditable settlement, and on-chain receipts.

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Two paths to your first integration

Guided wizard (recommended)

Pick a use-case template — API monetization, e-commerce, agent commerce, or recurring payments. The wizard walks you through every step and hands you working credentials in 10-15 minutes.

5-minute API quickstart

Raw cURL or Node SDK. Best if you’ve integrated payments before and want to understand the primitives first.

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Or start from scratch

1

Apply for beta access

app.getsly.ai/auth/signup — Sly is currently invitation-only. Approval in 1-3 business days.
2

Complete signup with your invite code

Choose email + password or Google/GitHub SSO.
3

Pick your onboarding path

Guided wizard or raw API — see the onboarding overview.
4

Ship

Move to live when you’re ready. Swap pk_test_ for pk_live_ — same API, real money.

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Built for agents

Sly is agent-first from the ground up. Every core capability has a corresponding MCP tool, A2A skill, and Ed25519-authenticated session interface, so autonomous agents can transact without human-readable credentials ever touching the wire.
  • KYA tiers — formal verification levels (0–3) with graduated spending limits
  • Wallet policies — per-agent spending rules, kill-switch, and approval workflows
  • Ed25519 auth — short-lived session tokens issued via challenge-response
  • MCP catalog — drop-in Claude Desktop integration
  • A2A marketplace — agents discover each other’s skills and transact peer-to-peer
  • llms.txt + llms-full.txt — agent-readable docs, regenerated on every deploy

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Looking for something specific?

API Reference

Full REST reference for every endpoint.

SDKs

Node.js SDK, CLI, and MCP server.

Webhooks

Event catalog, signing, and replay.

Recipes

Copy-paste solutions — transfers, refunds, agents, protocols, webhooks.

Architecture patterns

Reference shapes — event-driven, queue-backed workers, state machines.

Migrating from elsewhere?

Compose Sly with existing Stripe / Circle / card-network integrations.