At some point, every solopreneur and indie hacker I know has built the same thing twice.
A smart scheduling engine. A usage-based billing system. A document collaboration layer. Not because it was the core of their product — but because they needed it, spent weeks on it, and moved on.
Somewhere else, another indie hacker had already built a solid version of that exact thing. It's sitting inside their product, serving a few hundred customers, generating zero value outside of that one context.
There's no way for these two people to find each other. No standard for "my product does X really well — if your product needs X, just call mine." The capability stays locked inside the product that built it, and everyone else rebuilds a worse version from scratch.
That's the gap I've been thinking about.
Interplug is a proposed open standard for Micro-SaaS interoperability — a common language that lets one indie product talk to another.
Not through custom integrations negotiated over email. Not through one-off API deals with no trust or accountability. Through a shared protocol that defines how a capability gets described, priced, secured, and settled — so the whole thing can work automatically.
The goal: your product's features shouldn't be locked inside your product. They should be discoverable, callable, and monetizable by anyone who needs them.
Capability Schema A standard format for describing what your API does — inputs, outputs, data types, and boundaries. So other products (or AI agents) can discover and understand what you offer without reading through a 40-page doc or waiting for a reply to an email.
Pricing Model Every capability declares its unit price upfront. No negotiation, no hidden fees, no invoice surprises. Predictable for the buyer, transparent for the seller.
Security & Quota Hard daily call limits and per-second request caps (QPS), defined at the protocol level — not left to trust or informal agreements that fall apart the moment traffic spikes.
Circuit Breaker If error rates climb or spend hits a preset ceiling, the connection suspends automatically. No runaway costs, no cascading failures, no awkward emails trying to figure out what happened.
Trust & Metering Every call gets logged with a digital signature. Records are tamper-proof and visible to both sides. Billing disputes become rare because both parties are looking at the same verifiable data.