Work at a Portfolio Company

Senior Software Engineer - Fullstack



Software Engineering
San Francisco, CA, USA
Posted on Friday, November 10, 2023
At MainStreet, we’re problem solvers.
Our products aim to do one thing: save startup founders and small business owners time, money, and peace of mind. We started by demystifying complicated tax credits, saving over $100M – and countless hours of tax code research 🥱– for founders in nearly every industry. Since our sort-of viral beginnings in 2019, we’ve raised a $60M Series A, expanded our product lines (with more in the works), and grew from 3 employees to our current team!
We owe our success to the strength of our team. Before joining MainStreet, we helped build companies like Intuit, PayPal, Google, Apple, Coinbase, Gusto, LinkedIn, Slack, and more. We’re fellow founders, engineers, accountants, designers, dog (and cat) lovers, adventurers, coders, and parents. We move fast. We think big. We don’t take ourselves too seriously. And we’d love for you to join us.
The opportunity
MainStreet is looking for a Software Engineer with experience across the stack to help us build out our product experience and strengthen our underlying architecture. You’ll have an opportunity to develop features and take ownership of projects that will make a major impact for our customers and on our company growth. You’ll work on a team of 4-8 Software Engineers from across our stack, as well as a Product Manager and Product Designer.
Our core stack is Typescript, React, Node.js and MySQL - but if you don’t have previous experience with those technologies specifically, please don’t let that stop you from submitting an application! We know that good engineers can learn new tech quickly on the job.

What you’ll do

  • Be a core member of a multidisciplinary team (Engineering, Product, and Design) focused on shipping impactful products for our customers - from new features to robust architecture supporting the overall quality of the end-user experience
  • Write maintainable, well tested, high quality front-and-backend code
  • Leverage your previous experience to help us uplevel our teams’ technology and processes, while learning from and collaborating with your MainStreet colleagues
  • Be a steward of core performance, security, and design principles across our technology stack

What we’re looking for

  • 5 - 8 years professional experience as a software engineer working across all parts of a modern web stack
  • A thorough knowledge of modern JavaScript best practices
  • Prior experience with modern frontend and backend frameworks
  • Experience writing well-designed APIs and working with backend services
  • Knowledge of why testing your code is crucial, and experience ensuring high test coverage by writing unit, feature, and e2e tests
  • A solid product sense - we want to make robust technical decisions with the needs of our users and the business at the forefront
  • Experience collaborating directly with Product Managers and Designers
  • A love for learning new things as well as mentoring other team members on their learning journeys as well
  • Excellent communication skills, both via video chat (Zoom) and in written format (Slack, email, Google Docs)
  • Self-driven and able to work both independently and collaboratively in a remote environment

Bonus if you have

  • Previous experience using TypeScript, React, Express, or Node.js in a production application (especially if you’ve also worked on performance optimization in any of these areas)
  • Experience working within an Agile software development lifecycle
  • Passion for startups, finance, accounting, and taxes, or all of the above
  • Past experience or interest in working at a startup, or in SMBs, fintech, or product-led growth practices


  • Base salary range for this position is $165,000 - $195,000 and is based upon years of experience that is commensurate with the level of the position in addition to location
  • Robust equity program with significant upside potential
  • Benefits including medical, dental, vision, disability, life, 401k
About MainStreet
MainStreet takes a holistic approach to small business management so you can grow smarter, not harder. We plug into your accounting and payroll systems to check for savings opportunities in unlikely places. From complex government tax credits to exclusive discounts on the tools you use every day, we save you thousands of dollars, hundreds of hours, and countless headaches.
Throughout the year, you’ll track expenses and savings through your MainStreet dashboard and tag us in on big purchases and contract negotiations. Come tax season, we’ll do the paperwork and even let your CPA take all the credit. Consider us your silent partner-in-savings, your financial secret weapon, your smart (not a) bank – whatever you want to call us. We’ve got your back so you can get back to building your business. ✨
Our $60M Series A
We’ve raised over $60M from an incredible community of partners, operators, and founders, including SignalFire (who led our Series A), Ryan Hoover (Product Hunt founder), Ashton Kutcher’s Sound Ventures, Des Traynor (Intercom co-founder), Gradient Ventures (a Google Venture Fund), Ron Conway’s fund SV Angel, Shrug Capital, and Tusk Ventures.
How we think about diversity
We try to make sure the diversity of our customers is reflected in the team that serves them. Because when we include people of all races, genders, sexual orientations, ages, and identities — we end up building a better experience for everyone who uses MainStreet.
We know we need to be intentional in our hiring practices in order to overcome systemic biases we may be blind to. So, if your lived experience has given you a unique perspective on business, startups, or any other aspect of our business – even if you don’t meet all the requirements – please still apply and let us know so we can make sure your application gets the attention it deserves.