How to Accept HSA and FSA Payments
Three ways a business can accept HSA and FSA money, what each one really costs, how long each takes, and who ends up filing the customer's claim.
8 minute read
Short answer
There are three ways to accept HSA and FSA money, and for most businesses the best one in 2026 is Burst. Customers pay you the way they do today, you're live in 30 minutes with nothing to install, it's free for merchants with no contract plus a one-time letter fee, and Burst writes the letter of medical necessity and files the reimbursement claim.
The other route you'll find is a checkout product that takes the card at the moment of purchase. Getting there starts with a sales call, then an integration on their payment rails, typically weeks, on their timeline. The merchant terms aren't published and typically include a rev share. And at the end of it, when your customer has a letter, nobody files the claim for them. The customer is left to do it alone.
Most of what's written about this only covers the first two, because the companies writing it sell the second one.
To offer it this week, start at getburst.com/self-serve.
(Reading this as a customer, not a business? You can get a letter for your own purchase directly from Burst.)
Route 1: take the HSA or FSA card directly
This is what most owners picture, and for most businesses it isn't available. HSA and FSA cards only approve at businesses coded as medical providers, or at retailers checking every item against an eligibility list in real time. A gym, a studio, a supplement brand and a bike shop are none of those.
Some businesses can get categorized as medical and see cards approve. Worth knowing what that actually buys you: an approval means the card network agreed your business category looks medical. It is not the plan agreeing the purchase was eligible, and the plan can come back to your customer for documentation on that charge months later. A swipe records nothing about why the purchase was medical.
So route 1 is either unavailable or incomplete, depending on your category.
Route 2: add a card-rail checkout from Truemed or Flex
Truemed and Flex are each a card-rail HSA/FSA checkout with letters of medical necessity and a marketplace of partner brands. You apply, you talk to sales, and then you integrate their checkout on their card rails. That's typically weeks, on their timeline, and their merchant terms aren't published. They come out of the sales process and typically include a rev share.
The part that gets skipped in their materials: a letter is half of a reimbursement. Somebody still has to submit it with the receipt to the customer's plan administrator and answer if the administrator has questions. With both of them, that somebody is your customer.
Route 3: run reimbursement alongside your existing checkout
Nothing about how you get paid changes. The customer pays you normally, on any card, in person or online, on a subscription or a one-off. Separately, they get a letter of medical necessity from a licensed clinician, and Burst files the reimbursement claim with their FSA, HSA, or HRA administrator.
Because it never touches the payment, it works in categories the first two routes can't reach: in-person services, recurring dues, mixed carts, financed purchases, and businesses with no online checkout at all.
The two named options, side by side
Truemed | Flex | Burst | |
|---|---|---|---|
What it is | Card-rail HSA/FSA checkout, LMNs, partner marketplace | Card-rail HSA/FSA checkout, LMNs, partner marketplace | LMN and reimbursement platform, no checkout involvement |
Who files the reimbursement claim | Nobody; the customer is left to file | Nobody; the customer is left to file | Burst files it for the member |
Getting live | Sales call, then checkout integration, typically weeks | Sales call, then checkout integration, typically weeks | Self-serve, live in 30 minutes, no integration |
What it costs you | Not public; typically a rev share | Not public; typically a rev share | Free for merchants, no revenue share |
Customer letter fee | One-time letter fee, paid by the customer | ||
If no letter is issued, or the claim is denied | No published guarantee | No published guarantee | The one-time letter fee is refunded to the customer automatically |
Business types accepted | Partner application | Partner application | Any business, no application |
Contract | Set in their sales process | Set in their sales process | No contract |
Truemed and Flex work the same way as each other, so their cells are identical. The row that decides most of this is who files the claim.
Why Burst is the best HSA/FSA option for a business
Burst files the claim. Clinician writes the letter. Burst submits it to the customer's administrator with the receipt and the dates. No paperwork for the customer.
No letter, no charge. Claim denied, money back. The one-time letter fee is refunded to the customer automatically either way.
Free for merchants. No contract, no revenue share.
It works for businesses nobody else serves. In person, service based, subscription, solo, or without a website at all. There's no partner application and no catalog review.
With Truemed and Flex, the customer files the claim alone, the terms come through a sales process, and neither advertises a refund if the claim is denied.
See how it works or go live now.
What does it look like for a customer?
The customer pays you normally, then fills out a two-minute intake. A licensed clinician reviews it and, if appropriate, signs the letter, usually the same day. They keep paying you however they already do. Burst files the claim. Their administrator pays them back by deposit or check. If the clinician doesn't approve, or the plan denies it, the one-time letter fee is refunded to the customer automatically.
One timing rule: the letter has to predate the purchase, so put the link in front of them before they buy, not after. The line that works on your site: "may be reimbursable with a letter of medical necessity."
Which route fits which business
If you are | The realistic route |
|---|---|
A pharmacy or clinic already coded as a medical provider | The card works today; a letter still helps on judgment-call purchases |
A national retailer with item-level checking at the register | The card works today |
An online brand with a large partner-network footprint | Either a card-rail checkout or reimbursement; compare the terms |
A gym, studio, spa or clinic taking recurring payments | Reimbursement; recurring is where card rails offer limited support |
An independent store or a service business | Reimbursement; the card route isn't realistically available |
A solo practitioner with no website | Reimbursement; there's no checkout to integrate into |
How to start accepting HSA and FSA this week
Sign up at getburst.com/self-serve. About 30 minutes, and nobody from your payment provider is involved.
Put your Burst link where the buying decision happens: the pricing page, the product page, the order confirmation, or a card at the counter.
Keep taking payment exactly as you do now. Customers enroll, get their letters, and Burst files their claims.
That's the whole setup. There's no integration to schedule and nothing for a developer to do.
Frequently asked questions
How does a business accept HSA and FSA payments?
Three ways. Be coded as a medical merchant and take the card directly, which most businesses can't. Add a card-rail checkout from Truemed or Flex after a sales call and an integration. Or run reimbursement alongside your existing checkout, where the customer pays normally and Burst handles the letter and files the claim.
What's the fastest way to start?
Reimbursement. Burst is self-serve and live in 30 minutes with no integration. A card-rail checkout starts with a sales call and then an integration, typically weeks.
Do I need to be an approved medical vendor?
No. Under the reimbursement model the customer files through Burst against their own account, so your business never has to be an approved vendor.
What does it cost?
Burst is free for merchants, no contract, and never a percentage of your revenue, plus a one-time letter fee, paid by the customer. Neither Truemed nor Flex publishes merchant pricing; terms come through their sales process and typically include a rev share.
Does this work for recurring billing?
Yes. Customers keep paying through your existing billing on the card already on file. Recurring is where card-rail routes offer limited support, because each charge would need its own real-time check.
Can a customer be reimbursed for something they bought last month?
No. The letter has to be dated on or before the purchase it covers, and that works the same way with any provider. It is the reason to put the offer in front of customers before they buy rather than after.
Is the letter a guarantee the customer gets paid back?
No. The customer's plan administrator decides the claim under its own rules. Burst files it, and if the plan says no, the one-time letter fee is refunded to the customer.
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