Stablecoins have had four distinct eras.
1.0 — Trading. Getting in and out of crypto without touching a bank. The original use case, dating back to 2013.
2.0 — DeFi. Liquidity, lending, yield. The protocol era that made stablecoins load-bearing infrastructure for decentralised finance.
3.0 — Payments. Cross-border transfers, merchant settlements, payroll. What most people today think stablecoins are for.
4.0 — Agentic. Agents don't use payment links. They don't have billing accounts. They hold stablecoins, pay in seconds, and settle without human approval.
The builders who design for 4.0 now, while most of the market is still building for 3.0, are the ones who will own the infrastructure when agents become the dominant economic actor.
Most of what's being built today will need to be rebuilt.
The ones who build for 4.0 first won't have to.