Every engineer who's worked on billing knows the pain. You're not fixing bugs, you're rewriting logic that already worked, just to support yet another use case, for one more customer.
If you've ever maintained a billing system, you know exactly what I'm talking about. The constant fear of touching the billing logic. The endless edge cases. The growing pile of "temporary" workarounds that become permanent fixtures.
And before you know it, the same input starts producing different outputs. It’s not your fault. You just didn’t want to rebuild billing from scratch. So you patched. And kept patching.
Even teams with solid engineering fall into this. Look at what happened with Cursor.
They went from 500 to unlimited requests. Within days, users were seeing zero usage, or huge unexpected overages. If it happens to well-resourced teams, it can happen to anyone.
So why not just use Stripe?
Stripe works well, for the basics. But it’s a closed product, deeply tied to its own ecosystem.
The moment your pricing grows more complex, hybrid models, credit-backed billing, usage metering, you start working around Stripe, not with it.
- Want to bill through credits? Good luck.
- Need invoices to plug into internal tooling? Wrap the API.
- Want to override discounts for one customer? Write another patch.
Stripe doesn’t fail. But it locks you into workflows you can’t evolve.
So you write background jobs. You wrap the system. You stop trusting the calculations. And billing becomes a black box your team avoids touching.
We've seen this pattern repeat itself. Across startups, infra companies, even teams with solid engineering muscle.
One of them, Simplismart, put it best:
“We are an Infra company, and hence pricing changes a lot really quickly. While we were using one of the other billing tools, the initial setup was good, but as soon as we started to roll out changes, everything seemed to break from regenerating invoices, credit adjustments, partner billing, and more…
We were left with close to no support, and now that we have moved to Flexprice, the comfort of close to real-time support is just such a breather. The team is really nimble with requests and understands the space and requirements really well, with an almost spotless execution.”
— Shubhendu Shishir, Head of Engineering, Simplismart
So what’s the better alternative?
Closed source billing systems are optimized for the average case. But your edge cases are what define your product, and that’s where closed systems fail.
You try to fit your logic into someone else’s model. When it doesn’t fit, you patch it. When it breaks, you file a ticket.
And the deeper your pricing stack gets, the more boxed-in you feel.
Billing shouldn’t work like that. Not when it controls money, trust, and customer experience.
Open source changes that, it gives you:
- The ability to understand how system works
- The freedom to build logic that reflects your business, not a vendor’s roadmap
- A way to contribute back when you solve something new, so others don’t have to reinvent it
Flexprice is open-source billing infrastructure designed for what Stripe and closed vendors can’t do:
- Handle real-world pricing complexity
- Let you define logic around usage, credits, plans, and grants
- Keep billing inspectable and composable, like the rest of your stack
- Give you the option to self-host or plug into our managed cloud
- Support hybrid billing: credit wallets, usage tiers, subscriptions, and everything in between
Where we are, and what’s next
We recently launched five foundational features in five days as part of our Commit Launch. Check that out!
Each of these features reflects months of conversations with teams navigating real billing pain, engineers trying to bridge gaps with glue code and finance leaders fighting for visibility into revenue.
This momentum is just the start. Our public roadmap is open for a reason. We want you to build with us.
You can see what’s coming, suggest what should come next, and track how we prioritize across use cases.
We believe billing infra should evolve in the open, visible, extensible, and aligned with how real teams ship pricing.
⭐ Star us on GitHub to follow our progress
🤝 Join our community to share feedback and collaborate.
Top comments (2)
Been burned too many times by billing systems that fall apart with real-world logic. Stripe’s great until you need to do anything beyond the basics.
Makes so much sense, my developer colleague strongly agreed after reading this!