What is pay-per-call AI?
Last Updated: April 28, 2026
Pay-per-call AI is a billing model where each API call is priced and settled individually. Per-token for LLMs, per-image for image generation, per-second for video, per-request for data APIs. No subscription, no monthly minimum, no prepaid credits.
How it differs from the alternatives
- vs subscription: no monthly fee. Pay only for what you actually use; spend nothing on idle months.
- vs prepaid credits: no balance to top up, no expiring credits. Each call settles independently.
- vs API key seats: no signup, no billing email, no per-seat licensing. Authorize per-call with a signature.
Why AI agents need it
An autonomous AI agent making 50,000 API calls a day across 12 providers cannot hold a credit card, fill out 12 signup forms, and manage 12 billing portals. It needs to pay for one call right now, then another a second later, with no account anywhere.
Pay-per-call AI over a stablecoin (USDC) gives the agent exactly that: per-call authorization with a wallet signature, instant settlement on-chain, no persistent account. The mechanism that makes it work is the x402 protocol.
Pay-per-call AI on BlockRun
BlockRun is a pay-per-call AI gateway. 60+ models, image generation, video, music, and live data APIs — all priced per call, all settled in USDC over x402 on Base and Solana. No API key, no signup, no minimum spend. Free models are available for testing — no payment at all.
Provider cost + 5% margin at settlement — fully transparent on the pricing page.