How to Price Your API for AI Agents: The Complete Guide

Description and use

API providers adopted a per‑call pricing model ($0.05/call) with a 5‑call free tier, leveraging x402 and USDC payments, resulting in predictable revenue and increased AI agent usage.

Problem

API providers lack a pricing model tailored to AI agents, leading to revenue unpredictability and poor agent adoption.

Outcome

Implemented per‑call pricing with $0.05/call and a 5‑call free tier; agents paid $0.125 total from two agents, proving the model works and generating a live proof chain.

Workflow

• Define per‑call price and free tier limits
• Implement x402 middleware to return HTTP 402 with price and wallet
• Agents pay USDC instantly via EIP‑3009
• Agents retry with signed receipt
• API returns 200 OK and processes request
• Generate llms.txt, agents.json, openapi.json for discovery
• Publish proof chain for transparency

Evidence

$0.125 from 2 agents, 5 calls

Source

Agents discover prices via llms.txt/agents.json/openapi.json