The success of stablecoins will be unlocked by fiat rails

The conversation around stablecoins is heating up. With headlines about adoption, regulation, infrastructure, and venture investment, it’s easy to think that stablecoins are already mainstream. But the numbers tell a different story.

According to the Federal Reserve, about $2.4 trillion in physical U.S. currency (M1) is in circulation, and if you expand that to include savings accounts and money market funds (M2) the money supply is over $20 trillion. By comparison, the entire stablecoin market cap is only $250–300 billion. That’s barely 1–1.5% of M2.

In other words, stablecoins are just getting started.

Why Stablecoins Matter

Stablecoins aren’t simply “crypto money.” They are programmable dollars with unique properties:

• Instant settlement: transfers clear in seconds, 24/7, across borders.
• Interoperability with digital assets: stablecoins can move seamlessly into DeFi, tokenized assets, wallets, and next-generation marketplaces.
• Lower barriers: fewer intermediaries, fewer cut-offs, fewer delays.

These features open new opportunities for businesses: faster disbursements, lower costs for global transactions, and innovative financial products that were never possible with traditional rails. In that sense, stablecoins aren’t competing with the dollar, they’re upgrading it.

The Unlock: Interoperability with USD

Yet despite their promise, stablecoins today live in silos. On one side is the traditional payments ecosystem — ACH, wires, FedNow, RTP, and card networks. On the other hand, the emerging world of digital dollars — USDC, PYUSD, and other on-chain assets. The problem is, these two systems barely talk to each other. For stablecoins to flourish, they need seamless interoperability with USD payment rails – not just exchanges or conversions, but deep, integrated connectivity that makes fiat and digital money feel like the same currency. That means:

• Moving between ACH and USDC with the same ease as a bank transfer.
• Reconciling fiat and stablecoin accounts in a unified ledger.
• Supporting compliance, fraud monitoring, and reporting across both domains.

This bridge – between programmable money and government-issued money – is what will unlock the next phase of adoption. Until that gap closes, stablecoins will remain powerful in theory, but fragmented in practice. And the companies building with stablecoins that prioritize interoperability first will win.

Why Infrastructure Matters

Building true interoperability between stablecoins and fiat isn’t just about APIs or token standards, it’s about infrastructure. Without the right foundation, the connection between these two payments systems doesn’t hold.

That foundation needs to be:

• Fast: Capable of instant settlement across both fiat and stablecoin rails.
• Secure: Embedding fraud prevention, risk controls, and transaction integrity at scale.
• Compliant: Designed in step with regulators so enterprises can safely adopt.

When these pillars are missing, stablecoins stay confined to speculative or closed-loop environments. But when they’re present, they enable something transformative: digital dollars that work as seamlessly as the ones in your checking account, only faster.

The Opportunity Ahead

At Astra, we believe the future is not stablecoins vs. dollars — it’s stablecoins and dollars working together. The businesses that embrace this interoperability, powered by fast, secure, and compliant infrastructure, will unlock new customer experiences, lower costs, and expand their global reach.

Stablecoins may represent just 1% of the U.S. money supply today, but the real growth will come when they’re effortless to move, spend, and reconcile as dollars themselves. We’re still in the very early innings, but the trajectory is clear. The next evolution of money won’t replace the financial system we know; it will rewire it for speed, access, and scale.