---
title: "Flex + RevenueCat: Accept HSA/FSA payments for in-app subscriptions"
description: "Health and wellness apps can now accept pre-tax payments directly in-app — powered by Flex, managed through RevenueCat."
language: "en"
publishedAt: "2025-11-14T10:03:12Z"
updatedAt: "2025-11-14T10:03:12Z"
authors:
  - name: "Matt Berry"
    url: "https://www.revenuecat.com/blog/author/matt-berry"
category: "Company"
categoryUrl: "https://www.revenuecat.com/blog/company"
readingTime: 2
canonical: "https://www.revenuecat.com/blog/company/flex-integration-announcement"
---

# Flex + RevenueCat: Accept HSA/FSA payments for in-app subscriptions

Health and wellness apps can now accept pre-tax payments directly in-app — powered by Flex, managed through RevenueCat.

## Table of contents

- [Why this matters](#why-this-matters)
- [How it works](#how-it-works)
- [What developers are seeing](#what-developers-are-seeing)
- [Available now](#available-now)

Developers can now accept HSA and FSA payments for in-app subscriptions through a Flex–RevenueCat integration, enabling compliant pre-tax transactions, streamlined subscription management, and access to a new payment channel already used by apps like Ladder.

We’re excited to announce a new integration with [**Flex**](https://www.withflex.com/), enabling developers to accept HSA (health spending account) and FSA (flexible spending account) payments for in-app subscriptions for the very first time.

This update lets health and wellness apps offer compliant, tax-advantaged payment options, managed through RevenueCat and powered by Flex’s HSA/FSA technology.

Together, we’re unlocking a new, compliant revenue stream for developers and a smoother checkout experience for users eager to use their pre-tax dollars on eligible digital health products.

[Video](https://www.youtube.com/watch?v=SD5QBFrlHuE)

## Why this matters

Until recently, Apple’s in-app purchase (IAP) requirements limited developers to billing systems that didn’t support HSA or FSA cards.

For digital health apps, that created friction on both sides:

- Users couldn’t apply their pre-tax benefits to eligible subscriptions.
- Developers lost conversions or forced users into manual reimbursement flows.
Now, with Apple supporting external billing in the US, developers using RevenueCat + Flex can securely accept HSA/FSA payments while maintaining all the benefits of RevenueCat’s cross-platform subscription management, analytics, and entitlements.

The result: more compliant payment flexibility, better user experience, and higher conversion from a previously untapped payment channel.

## How it works

The integration connects Flex’s HSA/FSA payment processing with RevenueCat’s subscription infrastructure.

Developers can activate it in just two steps inside the RevenueCat dashboard — no major engineering lift required.

Once enabled:

- **Flex** ensures every transaction meets IRS and plan requirements.
- **RevenueCat** handles subscription renewals, trials, analytics, and entitlements across all platforms.
That means developers can launch new payment options fast — while keeping everything in sync with their existing billing systems (like Stripe or IAP).

## What developers are seeing

Early adopters like **Ladder**, the strength training app, have already seen measurable impact:

“The Flex integration through RevenueCat made it simple for Ladder to offer subscriptions via HSA and FSA cards — a major unlock for our users and an effective new growth lever.



We launched an email campaign educating potential customers about HSA/FSA eligibility using Flex’s marketing guide, and within a few weeks saw over 500 annual subscribers check out using their benefits.



From a technical standpoint, Flex’s seamless, native integration with RevenueCat functions just like our Stripe and IAP integrations — keeping our data and entitlements consistent while enabling a smooth experience across all of our purchase channels.” — **Ryan Mott, VP of Data Product at Ladder**

For developers, this opens access to **over $100 billion in annual U.S. HSA/FSA spending** — and makes it possible to capture that demand directly from their apps.

## Available now

The **Flex + RevenueCat** integration is available today for all Flex and RevenueCat customers.

👉 [Get started here](https://docs.withflex.com/developer-guides/integration/revenuecat) and start accepting HSA/FSA payments in-app in minutes.