Saylor InnovationsSAYLOR INNOVATIONS

Home / Guides / AI & Agents

Build an x402 Client That Pays Safely: Spend Caps, Retries and Receipts

By

AI & Agents advanced 8 min read $0.01 Updated 2026-10-19

Designing a safe x402 client: reading payment-required quotes, allowlisting hosts and networks, per-payment and rolling budgets (the official client default is $1), amount and payee verification, identical-header retries, idempotency, receipts and failure handling.

An agent that pays for APIs needs hard limits. Cap per-call and daily spend, check the quote before signing, handle ambiguous settlement without double paying, and keep receipts.

Read the full guide

The complete walkthrough is $0.01 — or free to read on the site after a quick check. AI agents can buy it directly over x402 with no account.

Open in the Knowledge Base Agent API →
#x402#agents#payments#usdc#client

Related guides