Introducing Vend: A Monetizable Blockchain Data API built using x402 & Alchemy
Dove into the x402 last week & built Vend - an API that leverages 3 of Alchemy's most important data APIs as well as webhooks to allow agents to query, monitor, & pay for data via x402
As agents continue to get more advanced and proliferate in usage, they are going to need access to live onchain data & that's exactly where Vend comes in
Our DevRel @asimfiles spent this week exploring x402, a protocol that lets agents pay for API access autonomously.
He built Vend to test it: an API using Alchemy's data endpoints + webhooks that agents can query and pay for directly.
Here's what he learned 🧵
Nov 4, 2025 · 7:59 PM UTC
Developers can use Vend to:
• Monetize blockchain data APIs
• Build pay-per-query services that agents can access autonomously
• Create new revenue streams from on-chain data
Agents can use Vend to:
• Autonomously pay for and access real-time blockchain data
• Query transaction histories, token balances, and NFT metadata on-demand
• Operate without human intervention for payments or authentication
This opens up entirely new use cases: autonomous trading bots that pay for their own market data, AI agents monitoring wallet activity, and self funding analytics tools that only pay for data they actually use.
As part of Vend, I also released a custom implementation of Coinbase's x402 express package called x402-onchain-verification
Unlike traditional x402 implementations that rely on facilitators, our package verifies transaction receipts directly on-chain before serving data - making it more decentralized and trustless
Haven't talked much about it but we've already seen 180+ downloads on the NPM package
Fork Vend or the x402-onchain-verification package - they are fully open source
Excited to see what folks build:
Github: github.com/usmaneth/Vend
x402-onchain-verification: npmjs.com/package/x402-oncha…
x402 protocol: x402.org
Alchemy API Docs: alchemy.com/docs





