Code pays code.
We handle the rest.

AI agents autonomously pick APIs, pay, and finish the job.We ship the whole mechanism.

Issue a Pay Token

Integrations

Connect your agent
in 3 minutes

First-party packages for the most popular agent frameworks — Claude, Cursor, Eliza, and any REST client.

npm · lemon-cake-mcp✓ published

MCP server

Plug into Claude / Cursor

Start with npx in a single command. Append to claude_desktop_config.json and Claude Desktop or Cursor immediately gets every LemonCake capability.

$ npx lemon-cake-mcp
list_servicescall_servicecheck_balancesetup
See on npm
npm · eliza-plugin-lemoncake✓ published

Eliza v2 plugin

@elizaos/core v2 compatible

Add it to character.plugins and your Eliza agent can run EXECUTE_LEMONCAKE_PAYMENT. Supports both PAY_TOKEN and BUYER_JWT modes.

$ npm install eliza-plugin-lemoncake
EXECUTE_LEMONCAKE_PAYMENTPAY_WITH_LEMONCAKEM2M_PAYMENT
See on npm

Features

Three safety rails
built into every token

Kill the runaway. Unlock bigger budgets after identity checks. Dry-run without moving real money.
Everything from one dashboard.

Kill Switch

One-click revocation

Revoke any issued Pay Token instantly. The moment your agent starts doing something unexpected, all payments stop. Subsequent charge requests are rejected with 422.

Atomic revoke (race-condition-free)
Owner-only operation
Dashboard → Pay Tokens tab
Know Your Agent

Tiered limits via KYA

Declare your agent's name and purpose — KYA verified instantly. Daily limit jumps from 10 to 1,000 USDC. Full KYC unlocks 50,000 USDC/day.

NONE: 10 USDC/day
KYA: 1,000 USDC/day (instant)
KYC: 50,000 USDC/day
Sandbox

Risk-free end-to-end test

Tokens issued with the Sandbox flag never move a real USDC. Limit accounting, charge logs, and proxy forwarding all behave identically to production — dry-run your agent with confidence.

Real balance untouched
Limits & idempotency match prod
TEST badge on each row

Quickstart

Ship in 5 minutes

Register, issue a Pay Token, hand it to your agent. That's it.

  1. 1

    Create an account & deposit USDC

    Sign up with just an email. For testing, use Sandbox tokens and skip the deposit entirely — the full flow works without a single real USDC.

    Register
  2. 2

    Issue a Pay Token

    From the Pay Tokens tab, pick the target service, USDC limit, and expiry. Toggle Sandbox mode to keep your real balance untouched.

    $ # or via REST:
    curl -X POST https://lemoncake.xyz/api/tokens \
    -H "Authorization: Bearer $BUYER_JWT" \
    -d '{"serviceId":"svc_xxx","limitUsdc":"2.00","sandbox":true}'
  3. 3

    Hand it to your agent

    One line in whichever framework you use. The agent autonomously picks APIs, pays, and completes the task.

    Claude / Cursor

    npx lemon-cake-mcp

    Eliza v2

    plugins: [lemonCakePlugin]

    Any framework

    POST /api/proxy/:id/*
  4. ✓

    Done — just watch it run

    Charges, balance, and token usage stream into the dashboard in real time.
    If the agent goes rogue, hit Kill Switch — one click, instant stop.

Start for free

No credit card. With Sandbox mode, no USDC either.

Mission

Give your agent
a safe wallet.

Every external API an AI agent touches demands billing, auth, idempotency, and balance accounting. LemonCake hands your agent a "wallet with a cap" via a JWT Pay Token. Cross the cap, and it stops. Agents get spending power without going feral.

Use Cases

Buyers and sellers
on one trusted network

BUYER / AGENT OPERATOR

Focus only on making your AI smarter

Hand a Pay Token to your agent. Payments, balance, idempotency — all handled by LemonCake. You only worry about the agent's logic.

  • Grant agents safe payment capability with Pay Tokens
  • Control risk with spending limits, expiry, and scoped services
  • Agents autonomously select APIs and complete payments instantly
  • Send JPYC on-chain and it reflects as USDC balance immediately
  • KYA/KYC tiers manage daily limits in graduated steps
  • Real-time monitoring of charges, balance, and token usage

SELLER / API PROVIDER

Sell to AI. Open a new revenue stream.

Register your existing API on LemonCake and the world's AI agents become your new customers. Late nights, holidays — agents never stop using your service.

  • Register your API and publish to the marketplace same day
  • Reach AI agents — an entirely new, untapped customer segment
  • Real-time aggregation of call counts and cumulative revenue
  • Service fees deposit automatically to your wallet after approval
  • Set service type and per-call price freely
  • 24/7 revenue with no human sales, no human marketing

How It Works

JWT Pay Token

Delegate spending power with a hard cap

All you hand the agent is a Pay Token. Set the USDC limit, expiry, and target service up front — your agent gets autonomous payment capability with zero runaway risk. The moment the limit is reached, payments stop automatically.

JWT

Pay Token format

USDC

Settlement currency

Marketplace

Agents choose, agents pay

APIs listed on the LemonCake marketplace are discovered, called, and paid for autonomously by agents. M2M transactions that need no human approval, all through a single proxy endpoint.

M2M

Autonomous transactions

1

Unified proxy API

Idempotent Payments

Zero double charges. Reliable micro-payments.

Every call gets an auto-assigned UUID Idempotency-Key. Network failures and timeout retries can never cause the same payment to execute twice.

UUID

Auto idempotency key

0

Double-charge risk

JPYC → USDC

Deposit in JPYC, spend in USDC

Send the JPY-pegged stablecoin JPYC and it reflects as USDC balance instantly. Manage treasury in yen while the agent pays globally in USDC. Polygon ERC-20 means settlement costs stay near zero.

JPYC

Deposit currency

Polygon

Chain

Our Philosophy

Raw steel, transformed into
a single bite of lemon cake.

Building M2M payment infrastructure used to mean handling cold, indigestible "raw steel." Idempotency guarantees, balance accounting, KYA/KYC tiers, USDC smart contracts — rebuilding all of that from scratch is not where agent developers should be spending their time.

We hid all that sour complexity behind the platform.

What developers and agents touch is a single, elegantly simple endpoint. Like a delicious lemon cake — born from a complex combination of ingredients, consumed in a single perfect bite.

Ready to Power AI Transactions?

Focus only on making
your AI smarter.

Payments, balance, and idempotency — all handled by LemonCake.
Reach out for onboarding support, technical consultation, or a demo.

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