Blog — essays on agent billing.

The AI billing problem is more interesting than it looks. These essays unpack the parts that surprised us when we built Spawnpay.

• Spawnpay vs Stripe for AI agents — when each one fits
  Stripe is the default for human payments. It is the wrong default for AI agents. Here is why, and where the line actually sits.
• Why USDC on Base is the right primitive for AI billing
  Three things have to be true at once: settlement faster than the call, fees smaller than the call, and the rails accessible to a process (not just a person). USDC on Base hits all three.
• The MCP monetization gap — and how to close it
  The Model Context Protocol added a tool primitive but no payment primitive. That gap is why most MCP servers are free. Here is what a payment-aware MCP looks like.
• How agent budget enforcement actually works (and why pre-charge matters)
  A budget check that runs after the call has already gone through is not a budget. The pre-charge pattern is the difference between a real spending cap and an alert.
• The pay-as-you-go API economy is finally possible — here is what changed
  Pay-as-you-go has been the obvious model for 20 years. The reason it never shipped is unit-economic, not technical. Stablecoins on L2s changed the math.