Full-Time

Senior Frontend Engineer

Finix

Finix

201-500 employees

Developer-friendly API for payment processing

Compensation Overview

$160k - $235k/yr

San Francisco, CA, USA

In Person

Category
Software Engineering (1)
Required Skills
JavaScript
React.js
Redux.js
Jest
Zustand
TypeScript
REST APIs
HTML/CSS
Requirements
  • 6+ years of production experience with modern web technologies (HTML, CSS/SCSS, JavaScript/TypeScript)
  • 3+ years of hands-on React development in complex, data-heavy applications
  • Solid experience with state management solutions (Redux, Zustand, Recoil, or similar)
  • Strong background in testing strategies and frameworks
  • Experience building responsive, accessible web applications
  • Understanding of RESTful APIs and modern build tools
Responsibilities
  • Build and maintain sophisticated payment dashboards and transaction management interfaces
  • Build performant, accessible, and reusable component libraries that scale across multiple products
  • Lead technical design sessions and drive frontend architecture decisions
  • Optimize application performance for high-volume financial data processing
  • Collaborate with Product, UX, and Engineering teams to translate complex payment workflows into intuitive user experiences
  • Mentor engineers and establish frontend development standards and best practices
Desired Qualifications
  • Experience in payments, fintech, fraud prevention, or financial services
  • Backend development experience with Java/Spring, Docker, Kubernetes, or AWS
  • Track record building secure, observable APIs and distributed systems
  • Experience with micro-frontend architectures or component library development

Finix provides a payment processing platform for software platforms, offering a developer-friendly API that lets SaaS providers, marketplaces, and e-commerce sites accept payments, handle merchant onboarding, and manage payouts. The API integrates into existing software to streamline payments and reduce operational complexity. It earns revenue by charging fees for API usage and related services, such as transactions or subscriptions. Finix differentiates itself by delivering a clean, easy-to-integrate payment solution that emphasizes reliability, security, and scalable payout and onboarding capabilities, enabling clients to grow revenue and cut costs instead of building payments from scratch. The company’s goal is to help software platforms run their payments efficiently, unlock more revenue from payment operations, and reinvest that income into their core products and teams.

Company Size

201-500

Company Stage

Series C

Total Funding

$200.5M

Headquarters

San Francisco, California

Founded

2015

Simplify Jobs

Simplify's Take

What believers are saying

  • Secured $75M Series C funding to scale full-stack infrastructure.
  • Launched Checkout app and reader for untethered in-person payments.
  • Integrated Interac Debit expanding Canadian in-store merchant options.

What critics are saying

  • Stripe undercuts with lower fees and global reach eroding SaaS share.
  • CFPB audits Finix underwriting halting onboarding within 12 months.
  • Finix personal finance dashboard dilutes B2B brand in 3 months.

What makes Finix unique

  • Finix connects directly to Amex, Discover, Mastercard, Visa as full processor.
  • Modular API enables instant merchant onboarding and payout management.
  • Embeds Plaid for 40% cost reduction in bank verification flows.

Help us improve and share your feedback! Did you find this helpful?

Benefits

Competitive compensation

Generous PTO

Flexible health plans

Coverage for dependents

Inclusive parental leave

Growth & Insights and Company News

Headcount

6 month growth

0%

1 year growth

0%

2 year growth

-1%
Yahoo Finance
Mar 27th, 2026
Finix partners with Plaid to speed up merchant onboarding and cut payment costs by 40%

Finix, a full-stack payment processor, has partnered with Plaid to integrate bank verification directly into its platform. The integration embeds Plaid's authentication and identity APIs into Finix to support fast, secure bank account verification across merchant onboarding, payouts and payment management. The partnership enables businesses to instantly connect, verify and update bank accounts, helping reduce onboarding delays and mitigate fraud risk. Finix customers can access Plaid's authentication flow through no-code onboarding forms or embed it using APIs. The integration also enhances payouts by verifying account ownership before funds are sent, reducing payment returns and strengthening control over funds flow. According to Plaid, the seamless bank payment flow can reduce processing costs by up to 40% compared to card payments.

Boland Hill Media, LLC
Mar 27th, 2026
Square signs Steak Escape and other digital transactions news briefs from 3/27/26.

Square signs Steak Escape and other digital transactions news briefs from 3/27/26. * Block Inc.'s Square point-of-sale payments unit will provide terminals, kiosks, and kitchen-display systems and process payments for Steak Escape, a 23-location fast-food chain. * Visa Inc. said it has worked with Pinwheel, a platform for in-app bill management, to launch its Enhanced Subscription Manager service, aimed at helping consumers track and manage recurring charges. The number of subscriptions globally is expected to reach 12 billion by 2030, Visa says. * Finix Payments Inc. said it has integrated authentication and identity APIs from open-banking platform Plaid Inc. to enable fast bank-account verification throughout merchant onboarding, payouts, and routine payment management. * AccelPay, a payments platform specializing in the alcohol industry, has merged with ReserveBar, a technology marketplace serving the same business. Terms of the merger were not announced. * Collectly Inc., a billing and payments platform for health-care providers, has closed on its acquisition of Pledge Health, a provider of AI technology for the same market. Terms were not announced. * Christine Katziff is joining the board of directors at payments-sofware provider Flywire Corp. following a nearly four-decade career at Bank of America Corp. * Cents Technologies Inc., a payments-technology provider for the laundry industry, said it has closed on a $140-million Series C funding round led by Sumeru Equity Partners.

AstroMVP
Mar 26th, 2026
5 founder-built MVPs that turned into real businesses.

5 founder-built MVPs that turned into real businesses. March 26, 2026 Alireza Bashiri There's a persistent myth that founders need to either be technical or hire a technical co-founder to build a software product. I bought into that myth for years. I ran an agency partly because I believed founders couldn't do this themselves. I was wrong. And these five products prove it. Each one was built by a founder - most with limited or no coding background - using AI skills and Claude Code. They're not side projects or abandoned experiments. They're live products with paying users. Here's what they built, how they did it, and where they are now. 1. Finix - personal finance dashboard. What it is: A personal finance dashboard that connects to bank accounts, categorizes transactions, and gives users a clear picture of where their money goes each month. Think Mint, but actually maintained and with a functional UI. How it was built: The founder used the SaaS Builder skill to set up the full-stack architecture - auth, database, API routes, and the dashboard layout. The Plaid integration for bank connections was described in plain English and the agent implemented it. Total build time was about 10 days because financial data handling required extra attention to error cases and data validation. Where it is now: Finix has a growing user base and recently introduced a premium tier with budgeting features and financial goal tracking. The founder hired one part-time developer to handle the Plaid edge cases and recurring data sync jobs. The core codebase from the original skill-powered build is still running. Cost to build: Under $100 in skills and API usage. The agency quote the founder received before trying skills? $35,000. 2. Tradezo - marketplace for secondhand goods. What it is: A niche marketplace for buying and selling used professional equipment. Think Craigslist meets eBay, but focused on a specific vertical with verified sellers and escrow payments. How it was built: The founder combined the SaaS Builder skill with a custom description of the marketplace features - listings, search, seller profiles, messaging between buyers and sellers, and Stripe Connect for split payments. The build took about two weeks because marketplace logic (two-sided transactions, escrow, disputes) is inherently more complex than a single-user SaaS. Where it is now: Tradezo processes real transactions every week. The founder bootstrapped it entirely. No investors, no co-founder, no agency. The marketplace model means revenue grows with transaction volume, and the escrow feature built trust early, which is the hardest part of any marketplace. Key insight: The founder told me the SaaS Builder skill saved him from the biggest marketplace trap - overbuilding the buyer experience and ignoring the seller experience. The skill's patterns forced him to think about both sides equally. 3. ReplyQ - customer reply management tool. What it is: A tool for e-commerce sellers to manage customer messages across multiple platforms (Amazon, eBay, Shopify) from a single inbox. Prioritizes messages by urgency, suggests replies, and tracks response times. How it was built: SaaS Builder skill for the core architecture plus detailed descriptions of the platform integrations. The founder was an Amazon seller who was personally drowning in customer messages. He built the tool for himself first, then realized every seller he knew had the same problem. Where it is now: ReplyQ has paying customers across three platforms. The suggested reply feature - powered by AI with context from the customer's order history - is the feature that drives conversions. People sign up for the unified inbox and stay for the smart replies. Build time: About a week for the core product. The platform API integrations took another week of iteration because each platform's API has different quirks. Total cost under $80. 4. Rentee - rental property management. What it is: A property management tool for small landlords. Tracks rent payments, manages maintenance requests, stores lease documents, and sends automated reminders. Built specifically for landlords with 1 to 20 units who can't justify enterprise property management software. How it was built: The founder is a landlord with five rental units and zero coding experience. She grabbed the SaaS Builder skill and described every feature based on her own workflow. "I need a place to see which tenants have paid this month. I need tenants to submit maintenance requests. I need to store lease PDFs." The agent built exactly what she described. Auth, a landlord dashboard, tenant portal, payment tracking, document storage, and automated email reminders for upcoming rent due dates. The whole thing was live in 5 days. Where it is now: Rentee has landlords across three states using it. The founder charges $12/month per unit, which means a 10-unit landlord pays $120/month. It's not a venture-scale business, and she doesn't want it to be. It covers her mortgage and solves a problem she had personally. Why it worked: She didn't try to compete with Buildium or AppFolio. She built exactly what a small landlord needs and nothing more. The skill made it possible to match that tight scope in days instead of months. 5. adworthy.ai - ai-powered ad creation platform. What it is: An ad creation platform that generates ad copy, images, and campaign variations for small businesses. Users pick a template, describe their product, and get ready-to-post ads for Facebook, Instagram, and Google. How it was built: This is probably the most documented build in its portfolio. The founder used the SaaS Builder skill and described an ad creation workflow with 300+ templates, Stripe billing, and a generation pipeline. Three days from idea to live product. Where it is now: adworthy.ai has paying customers and processes thousands of ad generations per month. The founder has expanded the template library and added team collaboration features - all using the same skill-powered workflow that built the original product. Build time: 3 days. This is the fastest zero-to-revenue timeline I've seen from a skill-powered build. The founder had a clear vision, described it precisely, and the agent executed. What these five have in common. Every one of these founders had three things going for them: They solved their own problem. Finix's founder wanted to track his spending. Tradezo's founder was buying used equipment and hated the existing options. ReplyQ's founder was drowning in customer messages. Rentee's founder managed her own properties. adworthy.ai's founder needed ads for his own business. None of them built on speculation. They kept the scope tight. Nobody tried to build a platform on day one. They built one thing well, launched it, and expanded based on what users actually wanted. The skill files made this possible by removing the architecture overhead. When your foundation is solid from day one, you can add features incrementally without rewriting anything. They moved fast. The longest build on this list took two weeks. The shortest took three days. Speed matters for MVPs. Not because of competition - because of momentum. The longer it takes to ship, the more likely you are to talk yourself out of it. If you've got an idea and you've been waiting for a technical co-founder or saving up for an agency, stop waiting. Grab the SaaS Builder skill and start this weekend. Frequently asked questions. Can a non-technical founder really build an MVP with AI skills? Yes. Three of the five founders in this article had no coding background before they started. They used AI skills with Claude Code, describing features in plain English. The skill handles architecture decisions, file structure, and production patterns. The AI agent writes the code. Your job is to describe what you want clearly. How much does it typically cost to build an MVP with skills? Skill files cost $29 to $59 each. Most founders spend $29 to $100 on skills plus $20 to $50 on AI agent API usage during the build. Total cost is typically under $150. For context, agency quotes for similar MVPs range from $10k to $40k. How long does it take to go from idea to live product? The five examples in this article ranged from 3 days to 2 weeks. The speed depends on scope and how clearly you can describe what you want. Most founders with a focused idea and the right skill ship a working MVP within one week. Can the code from an AI skill scale as the business grows? Yes. Skills generate real production code with proper architecture - not prototype-quality throwaway code. Several of these companies later hired developers who built new features on top of the existing codebase without needing to rewrite it. The architecture holds because it's based on patterns from apps that are already running at scale.

Boland Hill Media, LLC
Mar 13th, 2026
Eye on POS: Restolabs Conversions Are a Bump for Restaurants; Finix Launches a Checkout App and Reader

Eye on POS: Restolabs conversions are a bump for restaurants; Finix launches a Checkout app and reader. Restaurateurs generally will seek any edge to persuade consumers to spend their dining dollars with them. Online-ordering platform Restolabs says it now offers independent restaurants similar services to those used by enterprise-level restaurants, which could potentially increase their online conversion rates. Meanwhile, Finix Payments Inc. released its mobile point-of-sale app and companion card reader that can untether a sale from a countertop. New York City-based Restolabs said the updated service is designed around the conversion rate, something it says smaller restaurants rarely get a chance to optimize for. Among the features are wallet payment acceptance from Apple Pay and Google Pay users, prompts that encourage add-on items, and menus designed for clarity and navigation. Restolabs says these services may have required multiple vendors in the past, but are available in one bundle from it. Pricing ranges from $55 to $159 monthly on an annual basis. Month-to-month, Restolabs charges from $69 to $199. "Digital ordering should feel intentional, branded, and designed to convert because every direct order is an opportunity for the restaurant to build its own customer base," Sruthi Sekar, Restolabs cofounder, says in a statement. In related news, San Francisco-based Finix says its new Checkout app, for iOS devices, and companion card reader, are meant to enable merchants to accept payments wherever they may be, such as at events, in aisles, or elsewhere. In addition to payment acceptance, the app also enables customer profile management and the ability to send digital receipts via email or text. Finix, which launched in 2019, says all app transactions are available on its platform, where merchants can also manage reporting, reconciliation, customer data, and related financial workflows.

FinTech Magazine
Oct 23rd, 2025
Finix integrates with Interac to expand its payment options in Canada

Finix integrates with Interac to expand its payment options in Canada. The integration of Interac(R) Debit into the Finix platform gives Canadian merchants and consumers more ways to pay in-store SAN FRANCISCO, Oct. 23, 2025 (GLOBE NEWSWIRE) - Finix, the full-stack payment processor enabling businesses to accept and send payments online and in-store, today announced a new integration with Interac Corp. (Interac), a leading Canadian payments provider. The integration with Interac Debit brings in-store payments to Canadian merchants on the Finix platform, a significant milestone in the company's rapid expansion of its payment offerings in Canada. In-store payments are essential for many small and medium-sized businesses in Canada. With Interac Debit now available through Finix, merchants can offer customers more flexibility in how they pay. Together, Finix and Interac are empowering Canadian businesses to modernize their payment infrastructure while providing customers with secure, convenient options to pay how they choose. "Payments should be simple, not stitched together," said Richie Serna, CEO of Finix. "Our work with Interac makes it easier for merchants in Canada to accept in-store payments the way customers actually want to pay. Finix is building the infrastructure that lets businesses focus on growth, not payment complexity." "This integration with Finix reflects our commitment to providing secure and convenient payment solutions for Canadians and merchants," said Glenn Wolff, Group Head & Chief Client Officer at Interac Corp. "By expanding access to Interac Debit through the Finix platform, we're helping merchants meet the evolving payment preferences of their customers and helping support the modernization of payments across Canada." Finix continues to grow its presence in Canada through local hiring, new partnerships, and long-term investment to help more businesses modernize their payment infrastructure. For more information, visit its blog. About Finix Finix is a full-stack payment processor enabling businesses to accept and send payments online and in-store. From startups to multinationals and publicly traded companies, Finix offers everything needed to deliver a world-class payments experience across the US and Canada. Leading software platforms, marketplaces, retail, and e-commerce businesses use Finix's universal payments API and dashboard to accept payments, automate workflows, enhance customer experiences, and quickly grow revenue. To learn more, contact its sales team.