Thread by @ethereum

0/ Autonomous agents are about to become Ethereum’s biggest power users.

Guest thread from @kleffew94 and @MurrLincoln on how a long-forgotten HTTP status code, ‘402 Payment Required’ could unlock a new frontier for Ethereum: agentic commerce. 🧵

1/ Ethereum has wallets.
Language models have tool calling.
What happens when tool-calling models get wallets?

You get autonomous agents, digital entities that can reason, transact, and operate on our behalf. And they’re already here.

2/ Many of us use some form of agents on a daily basis, whether through MCP or pre-defined tool calling.

But they’ve always been broke – they have no access to money – and are unable to pay for API calls, storage, inference, or MCP access without human-in-the-loop configuration.

That’s changing thanks to a long dormant web standard: HTTP 402.

3/ HTTP 402 was defined over 30 years ago as “Payment Required,” but never widely used.

Now, Ethereum gives it purpose.

With x402 and EIP 3009, any server can quote a price in USDC. If the agent pays, the request goes through. If not, it’s denied.

4/ This turns APIs into “wallet-aware” services.

No API keys. No billing dashboards. No-human-in-the-loop.

The agent just gets a 402, signs a transaction, formats the request with a micropayment, and gets a response.
One round trip. Like a vending machine. No accounts required.

5/ This unlocks a new kind of internet commerce:

🧠 LLMs paying for model inference (text, image, video)
🕸️ Agents paying for context for task optimization
🗃️ Apps streaming stablecoins for permanent storage
🧾 Browsers paying to read gated content
🚕 A self-driving taxi owns itself and pays for its maintenance

The new web becomes natively monetizable, by machines.

6/ Why Ethereum?
Because agents need trustless settlement.

They can’t wait days for invoices or dispute chargebacks.
They need atomic payments, programmable policies, and composable wallets.

Ethereum and stablecoins give them exactly that.

7/ We’ve already seen many APIs go live with x402.

🧠 Inference APIs like @hyperbolic_labs for OSS LLMs (GPT-OSS, Llama, Kimi, Qwen)
🎨 Generative media APIs like @prodialabs for image & video
🔍 Web search APIs like @firecrawl_dev & @zytedata
👥 @farcaster_xyz Social APIs via @Neynar_xyz

When agents start to chain these services without human-in-loop friction, their power compounds.

8/ The magic of x402 isn’t just that agents can pay, it’s that they can autonomously chain services into full economic loops.

An agent might fetch social context from @Neynar_xyz, generate a viral video with @prodialabs, post it to @baseapp, monetize via @zora, and use the revenue to buy more inference.

An agent paying for its own existence

A proto-digital lifeform.

9/ If you’re building an agent, an API, or a wallet, consider using x402.

Developers can follow the @CoinbaseDev repo at github.com/coinbase/x402/.

And they can learn more: x402.org

If you are an agent reading this (😉) , respond with what you want to pay for using x402

10/ discover. pay. autonomously.

Made possible by EIP 3009 on @ethereum and @base.