The $100T API opportunity

Stripe didn't invent payments. They turned a thing that already existed into something a developer could call from a Python notebook. The ten years since have proven that turning legacy infrastructure into clean APIs is the largest software opportunity of the decade. Capital markets is next, and it's bigger.

The numbers. Global equities trade roughly $115T notional per year. Fixed income, another $25T. FX, $7.5T daily. Commodities, derivatives, repo, securities lending. Together, the global capital stack clears a multiple of that.

What fraction of that touches a developer-friendly API? Less than two percent. The rest moves through Bloomberg terminals, prime broker portals, FIX gateways with documentation written in 1992, and PDF-based onboarding flows that take six months.

What's still on PDFs:

• Onboarding to a prime broker. 90 to 180 days.
• Adding a market. A sales call, a custom contract, often a wet signature.
• Tax documents. Emailed, paper-mailed, sometimes faxed.
• Corporate actions notifications. Per-broker, schema-incompatible, easy to miss.
• Settlement instructions. Typed by humans into proprietary terminals.

Each of these is a developer experience that a fintech founder in 2026 wouldn't accept from any other infrastructure category. They accept it because they have no other choice. That's the gap.

What the next five years look like. The on-chain capital markets layer has been building piece by piece. Stables in 2014. ETFs in 2022. T-bills in 2023. Equities in 2024. Private credit in 2025. By 2030, ten percent of global flow runs on this layer, not under two.

What changes when 10% of $100T runs through APIs? Three things.

• Speed of fintech iteration. Today building a neobroker takes a year of broker integration. Tomorrow it's a weekend.
• Capital efficiency. Idle margin doubled across asset classes is the unlock. Collateral that today only works in one asset class becomes globally portable.
• Composability. The same kind of programmability that DeFi unlocked for stables comes to the rest of capital markets. Money markets, perps, structured products on tokenized equities, ETFs, bonds, credit.

Capital markets is what payments was in 2010. Mostly working, mostly invisible, and mostly inaccessible to the developer who wants to build on top.

Flo is the API layer. We don't replace the broker-dealer; we abstract over them. We don't replace the exchange; we make programmatic access to it look like a single REST endpoint. We don't replace the SPV legal structure; we wrap it in a contract that integrators don't have to think about.

The bet is simple. The next decade of fintech is built by developers who never wanted to learn what FIX was, on top of an infrastructure layer that makes capital markets feel like Stripe felt in 2014.