Flex

Backend Engineer

5+ years building production backend services and APIs in typed languages; strong relational DB fundamentals; collaborative and proactive; comfortable with ambiguity; experience with AI tools is a plus.

Infrastructure Engineer

5+ years building and operating production infrastructure at scale; AWS; Postgres; Terraform; strong collaboration; remote startup mindset.

5+ years building production backend services and APIs in a typed language; strong relational DB fundamentals; collaborative and proactive; able to work in a fast-paced environment.

Frontend Engineer

5+ years frontend software development; strong web practices; proactive; fast-paced; collaborative; execution mindset; proficient with AI tools.

Product Designer

3+ years in product design, user-centric approach, strong Figma skills, cross-functional collaboration, AI-enabled design, remote-friendly, able to thrive in ambiguity.

Founding Solutions Architect

Solutions Architect

7+ years in Solutions Architecture or related roles; enterprise deal experience; API integration; payments/fintech experience preferred; strong written communication.

Partner Success Manager

2+ years partner/customer success and/or account management; startup experience; mid-market exposure; preference for B2B2C/consumer brands; fintech interest.

Title	Location	Date
Backend Engineer Full Time · $160K-$220K · 5+ YOE United States · Remote	United States Remote	May 1, 2026
Infrastructure Engineer Full Time · $160K-$220K · 5+ YOE United States · Remote	United States Remote	May 1, 2026
Backend Engineer Full Time · $160K-$220K · 5+ YOE United States · Remote	United States Remote	May 1, 2026
Frontend Engineer Full Time · $160K-$220K · 5+ YOE United States · Remote	United States Remote	May 1, 2026
Product Designer Full Time · $165K-$250K · 3+ YOE United States · Remote	United States Remote	May 1, 2026
Founding Solutions Architect Full Time · $160K-$260K · 7+ YOE United States · Remote	United States Remote	Apr 28, 2026
Partner Success Manager Full Time · $170K-$190K · 2+ YOE United States · Remote	United States Remote	Feb 28, 2026

Activities	HSA/FSA payment processingReal-time eligibility verificationMedical necessity documentationTelehealth consultation servicesCheckout integration software
Headquarters	US
Industries	FintechHealthcare
Name	Flex
Employees	30
Type	Private
Tagline	Enables health brands to accept HSA and FSA payments online.
Founded	2,023
Website	withflex.com
Latest Funding Round	Series A
Latest Funding Year	2,025
Latest Funding Amount	15,000,000
Latest Investors	First Round CapitalCore VC

Flex

About Flex