Full-Time
Senior Software Engineer
Platform and Infra
Posted on 9/24/2025
Flex
51-200 employees
Interest-bearing digital banking with expense tools
Compensation Overview
$150k - $225k/yr
Remote in USA + 1 more
More locations: Remote in Canada
Remote
 Software Engineering (2) |
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- Proficiency in NodeJS+Typescript and its ecosystem.
- An understanding of and interest in architectural patterns for highly available, scalable, low-latency, asynchronous systems
- Ability to hold yourself and the team to high standards.
- Strong communication (written and verbal) and interpersonal skills.
- Ability to provide in-depth evaluation of multiple technical directions and determine tradeoffs of each.
- Ability to make data-driven decisions on technical architecture and project prioritization.
- Exposure to modular monoliths along with the benefits and challenges they bring.
- Experience with any cloud based provider like Google Cloud, AWS, or Azure.
- Experience maintaining cloud-based infrastructure as code with tools like Terraform, Pulumi, or Cloudformation.
- Four or more years of relevant industry experience with a track record of shipping high-quality systems and platforms at scale.
- A strong work ethic
- Ownership over foundational systems shared across a variety of different products.
- Play a critical role in the development, design, and maintenance of Flex's platform, services, infrastructure, and dev tooling.
- Own problems end-to-end, thinking through everything from api contracts, data, scalability, security, observability, and metrics.
- Lead by example and mentor engineers in all aspects of planning, development and testing.
- Be a catalyst for driving best-in-class technology frameworks and tooling while staying engaged with the latest technology trends.
- Be on call, with the expectation to ability to solve problems and find solutions for the servicing team
Flex.one provides a digital business banking platform that lets companies earn interest on idle cash (up to 4%), manage expenses in real time, issue team cards, and send free domestic ACH and wire payments. It works by letting clients keep funds on the platform, which accrues interest, while offering real-time reporting, expense management, card issuance, and fee-free payments; revenue comes from service fees and interest on client cash. It differentiates itself by combining high-interest cash potential with a full set of banking tools in one platform, plus ongoing security audits and fraud protections. Its goal is to help businesses maximize cash utility and profitability by streamlining financial operations and providing cost-effective payments with added rewards, all supported by strong security.
Company Size
51-200
Company Stage
Series B
Total Funding
$423.2M
Headquarters
Miami, Florida
Founded
2020
Simplify's Take
What believers are saying
- $60M Series B from Portage Ventures funds scaling after quadrupling revenue and tripling $3B payments volume.
- $40M Maza acquisition adds 250,000 Spanish-speaking customers and 290% YoY growth engine.
- Atlar integration with Campfire ERP automates treasury, saving manual monitoring across dozens of accounts.
What critics are saying
- Maza integration fails within 6-12 months, destroying 250,000-customer base due to cultural friction.
- Ramp and Brex encroach on mid-market TAM with 10x scale and superior brand in 12-24 months.
- Atlar outages paralyze $3B payments workflow as Flex depends entirely on its treasury platform.
What makes Flex unique
- Flex delivers AI-native private banking unifying business and personal finances for high-net-worth owners.
- Owner Intelligence platform provides real-time insights, cash flow projections, and business health scores.
- Vertically integrated AI underwriting enables precise risk pricing and Net-60 Credit Card float.
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Benefits
Remote Work Options
Flexible Work Hours
Growth & Insights and Company News
6 month growth
↑ 3%1 year growth
↑ 9%2 year growth
↑ 0%Flex chooses Atlar for AI-Native treasury management. US-based Flex, the financial platform for business owners, has selected Atlar for AI-powered cash management and payments, with a native integration to its ERP, Campfire. Flex is one of the fastest-growing financial platforms in the US. Headquartered in San Francisco, the company is building an AI-Native Private Bank for Business Owners - unifying the entire lifecycle of money for business owners, spanning private credit, business banking, expense management, payments, and personal finance. Flex has raised over $100 million in total equity funding, including a recent $60 million Series B, and has grown revenue 4x year-over-year. The company joins a growing number of US-based companies selecting Atlar, as the platform expands across the Atlantic. A challenge shaped by speed and complexity. Operating a financial platform at Flex's scale means the finance team needs to know exactly where cash is at all times. With a business model that requires constant cash positioning, the team was spending significant time each day manually monitoring balances across dozens of banking and payment accounts with no unified view. Compliance added another layer of complexity: all payments required at least two levels of approval, but not all of the team's bank portals supported this, leaving gaps that had to be managed manually. Why Flex chose Atlar. Flex selected Atlar to bring all of these accounts into a single view with the controls the team needed, including a native integration with Flex's ERP, Campfire. "We needed a treasury platform that could keep up with the pace we operate at. Atlar gives us a consolidated view across all of our accounts and the real-time visibility we were missing." - Brian Ehrlich, Senior Director of Finance and Accounting at Flex. "Having real-time visibility, automated reconciliation, proper approval workflows, and a full audit trail in one place means less time on manual checks and more time on the work that moves the needle." - Jacob Martin, Controller at Flex. Atlar is proud to welcome Flex to Atlar, and excited to support the team as they scale. Get started. Want to learn more about Atlar? Book a demo or get in touch. Atlar'd be happy to show you why fast-scaling companies like Flex choose Atlar. Louis Emmerson Get new insights and guides in your inbox, monthly You can unsubscribe anytime. Most recent. March 2, 2026 Why Your NetSuite Setup Is Incomplete Without Bank Connectivity Most companies automate accounting in NetSuite but still move cash manually. Connecting your banks to your ERP closes that gap. February 11, 2026 Introducing AI Agents for Treasury Atlar is launching AI agents for treasury: autonomous workflows for cash positioning, payments, reconciliation, and forecasting, built on the full breadth of your financial data. Bank Connectivity February 10, 2026 Bank Account Management in Atlar: FBAR Reporting and Signatory Tracking Atlar now includes FBAR reporting and signatory tracking, built on the same bank connectivity that powers your cash management and payments. January 8, 2026 How AI Is Changing Bank Reconciliation AI-powered bank reconciliation is quickly replacing manual spreadsheet matching, shrinking month-end close from days to hours or minutes. Customer stories December 9, 2025 How Mangopay Unlocked €20M in Idle Cash and Achieved a 6.1x ROI With Atlar Atlar has given Mangopay a treasury foundation that matches the scale of its business: secure, efficient, and forward-looking. Read about their journey. Customer stories December 4, 2025 How Liberis Saved 1,600 Hours a Year and Turned Treasury Into a Strategic Advantage With Atlar Liberis wanted a treasury function that matched the scale and pace of its business. With Atlar, it gained efficiency and control to support its next phase of growth.
Flex raises $60M Series B to scale its AI-native private bank for high-net-worth business owners.
Flex raises $60M Series B equity round to scale its AI native "private bank" for high-net-worth business owners. Flex raises $60M Series B equity round to scale its AI native "private bank" for high-net-worth business owners discover more chai edtech tea drinks drink beverage crowdfunding masala chai crypto cardamom flex raises $60M Series B equity round to scale its AI native "private bank" for high-net-worth business owners. Flex has closed a $60 million Series B equity round led by Portage Ventures, bringing total equity raised to $105 million. In the last year, the company has quadrupled revenue and tripled its payments volume to $3 billion. as it scales its all-in-one business and personal finance platform for high-net-worth middle-market business owners. San Francisco, Dec. 04, 2025 (GLOBE NEWSWIRE) - Running a profitable middle-market business has become one of the most complex financial jobs in America, with owners often juggling more than ten disconnected systems to manage their money. Flex was created to give these high net worth owners a single place to run both their business and personal finances.
Flex has raised $15 million in Series A funding to enhance its platform that allows online retailers to accept HSA and FSA payments, as reported exclusively by CEO Sam O'Keefe to Axios.
Flex, a startup providing personal finance software for business owners, has acquired Maza, a finance app for Spanish-speaking consumers in the U.S., for $40 million. This acquisition highlights the growing trend of mergers and acquisitions in the fintech sector.