Carbon Retirement, Built for AI Agents

Yes. On Carbonmark, AI agents can autonomously purchase and retire verified carbon credits through our x402 endpoint — a machine-payable API built for agentic transactions. The agent discovers available credits, requests a live quote, executes the retirement onchain, and receives a public Carbonmark certificate as proof, all without a human clicking through a checkout flow. Any agent framework that can make HTTP requests can integrate, and wallet-connected agents can transact directly through our Base MCP integration.

Carbonmark's x402 endpoint is an API that lets AI agents and other HTTP clients retire tokenized carbon credits on the Base blockchain using the x402 payment protocol. It exposes a simple four-step flow — discover, quote, retire, certificate — and publishes a machine-readable manifest at /.well-known/x402.json, so agent crawlers and registries can find and index the service automatically. Discovery and quote calls are free; payment only occurs when a retirement is executed.

No wallet with ETH is required. Carbonmark supports a gasless relay path: the user or agent signs a single EIP-712 authorization for the payment amount, and an executor submits the transaction onchain and covers the gas. This means agents can retire carbon with USDC alone — no Base account setup, no gas management, no bridging. Agents that do control their own funded wallet (for example, via Base MCP) can skip the relay and submit transactions directly.

Every retirement — human- or agent-initiated — resolves to a public Carbonmark certificate URL showing the project, vintage, tonnage, retirement date, and named beneficiary. The underlying transaction is recorded on the Base blockchain, so the retirement can be independently verified onchain by anyone, at any time. Additionally, for enabled carbon registries, retirement events occurring onchain are also linked to retirement events in the credit's host registry on a one-to-one basis. Autonomous doesn't mean unaccountable: your agent returns a link, and that link is permanent, public proof.

Calling the API is free — discovery, quotes, and integration carry no charge and no subscription. You pay only when a retirement executes: the quoted price includes the market price of the selected carbon credits plus the x402 fee, with no hidden costs added after the quote. Because quotes reflect live onchain pricing, your agent always knows the exact total before it commits.

No. Retirement permanently removes a carbon credit from circulation — the credit is burned onchain and can never be resold or reused, which is precisely what makes it a credible climate claim. That's also why the flow is quote-first: your agent receives the exact price, project, and tonnage before any payment is authorized, so nothing irreversible happens without an explicit, informed approval step. We recommend agents surface the quote to their user (or check it against configured limits, like a maximum price per tonne) before executing.

Any framework that can send HTTP requests can use the x402 endpoint directly. For deeper integrations, Carbonmark supports the Model Context Protocol (MCP) via Base MCP, allowing tools like Claude Code and other MCP-enabled agents to retire carbon from a plain-language instruction — for example, 'Retire 2 tonnes of carbon under $15 per tonne for Acme Corp.' See the integration docs for setup guides.