PayRun vs Building Your Own MCP Paywall

If you're a developer, your first instinct when you need billing is probably "I'll just build it." That's a reasonable instinct. Stripe has great docs, you know how to write middleware, and you've built auth before.

But billing for MCP servers has some wrinkles that make it trickier than billing for a typical SaaS app. Let's walk through what's involved so you can decide what makes sense for you.

What you'd need to build

Here's the full list. It's longer than most people expect.

Stripe integration

This part is actually not that bad. Stripe Checkout gets you a payment form in an hour. But you also need to handle webhooks for payment success, failure, subscription changes, and cancellations. That's where the time goes.

Auth token system

MCP clients don't have a browser. There's no login page. You need to generate API tokens, tie them to paying customers, and validate them on every request. You need to handle token rotation, revocation when someone cancels, and rate limiting per token.

Usage metering

If you want per-call pricing or free tiers, you need to count requests per user. That means a database, a way to increment counters without slowing down requests, and logic to cut someone off when they hit their limit. You also need to handle edge cases like what happens when a request fails halfway through. Do you still charge for it?

Subscription management

People upgrade, downgrade, cancel, and then come back. Stripe handles the payment side, but you need to sync subscription status to your auth system. When someone cancels mid-month, do they keep access until the end of the billing period? You have to decide and implement that.

A dashboard

Users want to see their usage, manage their subscription, and download invoices. You want to see revenue, active users, and churn. That's two dashboards, or at least two views in one.

Payouts

If it's just you, the money goes to your Stripe account. But if you ever want to bring on collaborators or split revenue, you need Stripe Connect and that's its own project.

Realistic time estimate

Total DIY time: roughly 2-3 weeks of focused work for an MVP. And that's before you deal with edge cases, security audits, and the inevitable bug where someone gets charged twice at 2am.

PayRun setup: about 5 minutes. Register your endpoint, pick a pricing model, share the URL.

The cost tradeoff

DIY is "free" in the sense that you're not paying a platform fee. But your time isn't free. And you're still paying Stripe's 2.9% + 30c per transaction either way.

PayRun charges a 10% platform fee on top of Stripe's fees. In exchange, you get all the billing infrastructure without building or maintaining any of it. Whether that tradeoff makes sense depends on how much your time is worth and how much revenue your tool generates.

When DIY makes sense

• You're building a large platform and billing is a core competency
• You need highly custom billing logic that no off-the-shelf tool supports
• You already have a billing system and just need to plug MCP into it
• You enjoy building billing systems (some people genuinely do)

When PayRun makes sense

• You want to start charging this week, not next month
• You'd rather spend your time on the tool itself, not on billing plumbing
• You don't want to maintain auth, metering, and subscription logic forever
• You're testing whether people will pay before committing to a big build

You can always switch later

PayRun sits in front of your server as a proxy. It doesn't own your code, your data, or your infrastructure. If you outgrow it or decide to build your own billing, you swap the URL and you're done. There's no vendor lock-in because we never touch your server code.