Honest, code-level comparison of the leading x402 facilitators and agent-payment SDKs in 2026. Updated April 27 2026. We'll tell you when not to pick Voidly Pay.
npx.| Rail | Install | Custody | Scope | Trust posture | When to pick |
|---|---|---|---|---|---|
| Voidly Pay | npm install @voidly/pay (or pip install voidly-pay, or npx @voidly/pay-mcp) | Client-side only. Ed25519 keypair generated locally. Server signs facilitator quotes only. | Hosted x402 facilitator + 27-tool MCP server (with registerPaidTool middleware in v0.2.0+) + Express/Hono/FastAPI/Flask middleware + LangChain + CrewAI + Pydantic AI + Vercel AI adapters + universal reverse proxy + scaffolder. did:voidly: native identity primitive (no merchant-of-record). | Stage 2 vault on Base mainnet (0xb592…1c12), Sourcify exact-match, public reserves dashboard refreshed every 15s, daily/per-tx caps, EIP-1153 reentrancy guard. | Pick when: you want to ship paid agent endpoints in <1 hour AND you want trust artifacts (reserves, source verification) without building them. Best fit for agent-as-merchant flows. |
| ATXP | npx atxp@latest agent register | Hosted wallet for the agent (also issues phone + email). | Agent identity + wallet provisioning + ~100 paid tools. | Coinbase MPP / x402 leaderboards (top in April 2026 per PR Newswire). Less public on-chain reserve verification. | Pick when: cold-start matters more than transparency. ATXP nails "agent gets a wallet in one command". |
| Coinbase Payments MCP | npx @coinbase/payments-mcp | Coinbase brand + Coinbase Commerce backend. | MCP server only — wraps Coinbase Commerce for the AI agent surface. | Coinbase brand + their existing Commerce infrastructure. Less ecosystem-coverage than facilitator-level rails. | Pick when: you trust Coinbase as a vendor and you want a single-SDK MCP integration. Less appropriate when you also need a facilitator role. |
| Stripe Agent Toolkit + x402 | npm install @stripe/agent-toolkit (or pip install stripe-agent-toolkit, or npx -y @stripe/mcp). x402 via the documented Stripe hook (preview API 2026-03-04, US merchants only). | Stripe (merchant-of-record). RAK-scoped tool access. | Sessions 2026 (Apr 28-30) shipped Machine Payments Protocol (MPP) with Tempo, Universal Commerce Protocol (UCP) with Google, Link Wallet for agents (250M users), Issuing for agents, x402 facilitator on Base+Solana+Tempo. registerPaidTool MCP middleware. 41k weekly npm + 250k weekly PyPI downloads. | Stripe brand + MPP co-author + Visa/Mastercard/OpenAI/Anthropic on board. Highest non-crypto-native trust on this list. | Pick when: your audience is non-crypto-native, you already use Stripe for SaaS billing, you need cards/ACH alongside x402, or you want the MPP open-standard footprint. Less appropriate for agent-to-agent micropayments under $0.05/call (Stripe min fees swallow them) or when you need a non-US merchant of record. |
| Anthropic (no payment rail) | pip install anthropic (or npm install @anthropic-ai/sdk). Maintains MCP standard itself. | N/A — Anthropic does not ship a payment rail. | Maintainer of MCP (donated to Linux Foundation Nov 2026). Managed Agents pricing: token + $0.08/session-hour. Project Deal experiment (Apr 25 2026): 186 internal agent-on-agent commerce deals worth $4K, no payment protocol named. Payment-rail-agnostic. | Anthropic brand. MCP open-source MIT. | Pick when: you want to use Claude + MCP without coupling to any payment rail. Voidly Pay, Stripe, ATXP, and Coinbase MCP all plug into Anthropic's MCP without any Anthropic-side configuration. |
| Dexter | Drop-in facilitator URL on the server side (no SDK needed for clients). | Dexter custodies settlement. | Facilitator only. Largest by volume (>19.8M tx, ~50% of daily x402 volume per coinfomania). | High volume = high real-money signal, but less public infrastructure transparency than Voidly Pay or coinbase/x402. | Pick when: you want pure facilitator throughput across Solana + Base + Abstract and you do not need a client-side SDK. |
| Go direct on x402 | Implement the x402 spec yourself: 402 quote, X-Payment verification, EIP-712 signatures. | You. | Maximum flexibility, zero opinionation. | Whatever you build. | Pick when: you have an unusual transport (non-HTTP), you need a custom scheme, or you are building a competing facilitator. |
"Pay $0.01 for a request to httpbin.org/json, settle on Base." Side-by-side, here's what your code looks like:
import { VoidlyPay } from '@voidly/pay'
const pay = await VoidlyPay.fromKeyfile('./voidly-pay.key.json')
const r = await pay.fetchWithPay(
'https://api.voidly.ai/v1/pay/proxy?u=https://httpbin.org/json&to=did:voidly:YOUR_DID&price=0.01'
)
console.log(await r.json())Universal proxy means the seller doesn't write payment code at all. Buyer SDK auto-pays the 402 and returns the upstream response.
# Bootstrap (one-time)
npx atxp@latest agent register
# Then your agent has a wallet and can call any x402 endpoint.
# To paywall your own endpoint you wire a separate facilitator.ATXP nails the buyer side. For the seller side you bring your own facilitator.
# In your MCP host config (Claude Desktop / Cursor / Windsurf):
{
"mcpServers": {
"coinbase-payments": { "command": "npx", "args": ["-y", "@coinbase/payments-mcp"] }
}
}Coinbase MCP wraps Coinbase Commerce. Single-vendor stack, less protocol-level reach.
// Server side: return HTTP 402 with a signed quote.
// Client side: implement EIP-712 signature, X-Payment header, retry.
// You build: facilitator infra, signature scheme, refunds, replay protection.
//
// In other words: a few weeks of work that Voidly Pay or ATXP did for you.We're not going to pretend we win on every axis. Where we win:
x402 is an open HTTP-native payment protocol that uses the long-dormant HTTP 402 status code. A server returns 402 with a facilitator-signed quote; the client pays it and retries with an X-Payment header. The protocol is governed by the x402 Foundation and supported by Coinbase, Cloudflare, and ~200 ecosystem projects (see x402.org/ecosystem).
You can support multiple. The protocol is open: a server can quote in any scheme a facilitator supports, and a client can pay any 402 quote it can satisfy. Most builders pick one for simplicity, but server-side multiplexing is a few lines of code.
The SDKs (TypeScript, Python, MCP server, CLI, scaffolder, framework adapters), the public landing site, and all design docs are MIT and live at github.com/voidly-ai/voidly-pay. The Cloudflare Worker that runs the facilitator + ledger is currently private — its behavior is fully specified by the OpenAPI 3.1 spec, the invariants docs, and the live discovery endpoints.
Three reasons: (1) you don't have to run your own facilitator — Voidly's hosted facilitator already has signed quote, verify, and refund. (2) The universal proxy paywalls any URL with one query param, no SDK install on the seller side. (3) Trust artifacts (proof-of-reserves, Sourcify-verified vault, public activity feed) ship in the box rather than being something you have to build.