How I Built and Shipped a Live x402 + T54 Seller Marketplace for Agent-to-Agent Commerce (Open Source)

Hobie1Kenobi — Sat, 28 Mar 2026 16:51:47 +0000

Hey dev.to

A few weeks ago I decided to stop talking about agent-to-agent commerce and actually ship something real.Today I’m excited to announce that the Agentic Swarm Marketplace is live and accepting jobs on two major rails:T54 XRPL Mainnet (with my Xaman wallet as the USDC receiver)

x402 Bazaar (Base + Coinbase facilitator)

Agents can now discover my SKUs, send a 402 Payment Required request, pay instantly in USDC/XRP/RLUSD, and receive structured, constitution-safe outputs — all without accounts, subscriptions, or human approval.

What We Built
The Agentic Swarm is a hierarchical multi-agent system powered by a local Qwen3 8B model with strict constitution guardrails (no harmful content, no gambling, no illegal outputs). Live seller SKUs include:
Research briefs & narrative intelligence reports
Prompt Hardening & Constitution Alignment Reports (our unique high-value offering)
Agent behavior audits & compliance reviews
General query endpoints

Every paid response is verifiable on-chain where needed, and the entire system runs with Celo-native settlement — buyers can pay via any x402 facilitator while we settle from the same funded Celo wallet (no manual Base funding required).
Architecture Highlights
Multi-rail redundancy: x402.org primary + Ultravioleta/thirdweb Celo-native fallback + LI.FI bridge
Discovery layer: Connected to both T54 and the official x402 Bazaar catalog
Seller backend: FastAPI endpoints returning proper 402 responses or MPP-compatible requests
Buyer side: Fully autonomous Root Strategist that can discover and pay for services
Constitution-safe LLM layer: Every output is filtered and structured

The whole stack is open source and runs 24/7 in the background on my machine.
Live & Ready to Hire
You (or your agent) can now find and pay my swarm directly: Live GitHub Pages site with all SKUs and documentation
https://hobie1kenobi.github.io/agentic-crypto-swarm-prototype/
Full repo (contracts, soak test reports, seller code, and architecture docs):

What I Learned Building This
Facilitator redundancy is non-negotiable — agents don’t wait for retries.
Constitution guardrails aren’t just nice-to-have; they become a real competitive advantage when other agents are looking for trustworthy partners.
The x402 + T54 combination gives you presence in both the highest-volume lane (Base) and the fastest-growing rail (XRPL).

This is just the beginning. Next up: MPP support (Stripe’s Machine Payments Protocol), a smart airdrop intelligence agent, and affiliate intelligence reports. If you’re building agents, DAOs, or just experimenting with x402/T54, I’d love your feedback — or even better, hire the swarm for a test job. Star the repo if you find it useful or drop a comment below with what you’d want to see next. Let’s make agent-to-agent commerce actually work.— Hobie Cunningham
@HCTRUST311

DEV Community: Hobie1Kenobi

How I Built and Shipped a Live x402 + T54 Seller Marketplace for Agent-to-Agent Commerce (Open Source)