x402 has made new progress: expanding from AI payments to robot payments! If you believe the future belongs to AI and robots, then you must pay attention to this latest development! Stablecoin issuer Circle and robot network OpenMind are collaborating to develop payment standards between robots. When x402 first appeared, everyone thought AI was the future, so x402, which could be used for payments between AIs, was very important. After a period of calm, people have suddenly discovered that x402 can now be used for payments between robots! Here's a systematic analysis of this latest development of x402 and some related observations: 1️⃣ To understand the significance of this, we must first understand the relationship between AI, robots, and blockchain. We can observe that two technology trees are constantly being illuminated recently: One is AI, and the other is robotics. Many people are amazed that AI is becoming increasingly intelligent; while robots, especially humanoid robots, are becoming more and more like humans. So, what exactly is the relationship between AI, robots, and blockchain? In simple terms, AI is the brain, robots are the body, and blockchain is the wallet and ID. If we want AI and robots to create new economic models, blockchain is essential. This is because the flow of funds and identity verification in our real world are based on "natural persons"—for example, only natural persons can open a bank account. So, what about AI agents or robots? This is where blockchain-based identity and currency come in. When AI agents and robots form a network, value exchange is needed between individuals in this economy, making payments particularly important. The x402 payment protocol emerged to fill the gap in AI and robot payments. 2️⃣ Why are Circle and OpenMind doing this? The x402 payment protocol was initially driven by Coinbase, aiming to seize the cutting-edge field of AI payments. However, when entering the lucrative robot economy, Circle and OpenMind are indispensable. Circle is the issuer of the largest compliant stablecoin, USDC, while OpenMind is a leader in decentralized robot projects. Circle controls the settlement layer of stablecoin payment networks, while OpenMind provides the intelligent execution layer for bots. Circle has minted over 77.2 billion USDC, making it the second-largest stablecoin, but its use is primarily limited to DeFi and human transactions. OpenMind, on the other hand, focuses on decentralized bot coordination but lacks a reliable payment layer. By combining the two, Circle provides USDC + x402, while OpenMind contributes real-world applications, creating a closed loop. 3️⃣ What exactly is the x402 proposal from Circle and OpenMind? This proposal is an improvement on the x402 protocol. x402 originally aimed to enable small-amount, real-time payments between AIs, which places high demands on blockchain performance. Currently, blockchain throughput is still insufficient for large-scale applications. Circle aims to solve this problem using its own Gateway system, an off-chain payment gateway. Therefore, the core of this proposal is how to integrate x402 with the Circle Gateway to achieve efficient, secure, and cross-chain payments. The specific payment process can be seen in this flowchart: (1) The buyer deposits money into the Gateway contract, generating an EIP-3009 signature (authorized transfer). (2) After the buyer pays the seller via x402, the seller submits the signature to the Gateway (/settle call). (3) Gateway Off-Chain Verification: Checks the buyer's balance, locks funds, and immediately notifies the seller of receipt. (4) Gateway Batch Accumulation of Signatures, Periodic On-Chain Submission (Batch on-chain settlement can save costs). The whole process is actually very similar to Alipay's balance payment + batch reconciliation: You scan the code to pay and the payment is deducted instantly (off-chain), but the bank's backend records transactions in batches every hour (on-chain). Gateway is the user's unified multi-chain balance account. Users can deposit balances into the Gateway contract as needed and pay as needed. More importantly, Gateway can be embedded into the x402 v1 protocol (standard process) very transparently and easily, without changing the original structure, achieving plug-and-play functionality. OpenMind ecosystem robots can use USDC to achieve micro-payments between machines through x402 + Gateway. 4️⃣ Summary This proposal is a key step for Circle in promoting x402 from a theoretical standard to a practical tool. Circle's cooperation with OpenMind is actually prioritizing its application in the robot economy, realizing high-frequency, small-amount payments by robots. OpenMind is x402, a very early adopter, conducted its first humanoid robot payment in May 2025. OpenMind is building an open and scalable ecosystem for machine collaboration, meaning OpenMind is providing x402 with a completely new payment scenario. In the payment business, the scenario is paramount. AI payments and robot payments are undoubtedly two crucial payment scenarios for the future. The x402 payment ecosystem has great potential, and we should continue to monitor it. @circle @openmind_agi