Founding Platform Engineer

Mosaic.tech; United States; On-site; USD 120,000 - 180,000; Full time

Benefits offered by this job

Equity stake

Fully remote team

Twice-yearly offsites

High-growth environment

Job summary

Rivet, a tax prep firm competing to simplify tax season, seeks an engineer to design and ship high-impact tools inside our platform. You will work directly with tax professionals and clients, influence the product roadmap from day one, and automate complex prep tasks using AI and data from various sources.

You will translate PDFs into structured CSVs, build integrations for legacy software, and help define our engineering culture and standards.

Qualifications

• 4+ years of engineering experience with ownership of shipped tools.
• Experience delivering internal tools or automation at speed.
• Ability to work in early-stage environments with evolving roadmaps.

Responsibilities

• Design and ship intuitive, high-impact tools embedded in our platform.
• Influence product roadmap and company strategy from day one.
• Create mods for legacy software and automate tax prep tasks with AI.
• Translate PDFs into structured CSVs with measurable accuracy.
• Help define engineering culture, tooling, testing, and review processes.

Skills

Engineering experience

Internal tools development

Ops automation

Async communication

Tools

Go

Python

React

PostgreSQL

GitHub Actions

Job description

Rivet is a tax prep firm built by technologists, not software salespeople.

Our goal isn’t to build another dashboard that wins design awards—it’s to eliminate the worst parts of tax season for real businesses. We combine corporate tax, personal tax, R&D credits, and bookkeeping into a single experience that just works.

Our software is designed to feel invisible: guide clients through their tax to-dos, automate the drudgery for preparers, and vanish from view when it’s not needed. It’s not about features—it’s about making people faster, safer, and less stressed. We measure success in time saved and dollars retained, not DAUs or engagement metrics.

We support 500+ of the fastest-growing companies in the US — including Cursor, Cognition Labs, and ModRetro. And while we may have just gotten started, this isn’t our first rodeo:

• Nick Abouzeid (cofounder & CEO) ran three growth teams at Ramp and previously led marketing at MainStreet ($3M → $15M ARR in 2 years)

• Kyle Christenson (cofounder & Head of Tax) spent six years auditing at the IRS, then joined MainStreet to handle their most complex claims

We're well capitalized to grow, profitable, and have raised two rounds from XYZ Ventures (first investor in Anduril) and 40+ executives from Ramp, Newfront, Stripe, Deel, & more.

Why this role is different

We’re not a feature factory, and we’re not building make-work. We hold a high bar for product quality, but we care more about what works than what’s trendy. A few principles we care deeply about:

• Ownership from first commit to production. Engineers design, build, ship, and maintain their work—no handoffs, no middle‑management mazes.

• Decisions happen at the edge. Engineers talk to clients and tax preparers directly. We optimize for speed and context, not committee consensus.

• No LARPing. We don’t do “agile” for its own sake. No sprints, no story points, no standups unless they help us ship better.

• Clear is kind. We surface problems early, talk about tradeoffs openly, and don’t sugarcoat. We’re kind by being honest, not by being vague.

• Pragmatic stacks. We pick tools that solve real problems. If it doesn’t help us ship faster, safer, or better, we don’t use it.

• Skin in the game. We ship things we’d be proud to put our name on—and if something breaks, we own it and fix it fast.

Our tech stack: Go (Connect RPC, Go Fx), Python (FastAPI, SQLAlchemy), React (TanStack, Tailwind), PostgreSQL, Railway, OpenTelemetry, Github Actions.

What you’ll do

We’re fully distributed — but if you want an office, we’ll help you find one through our investor network.

• Work with our tax team and clients to design and ship intuitive, high-impact tools, deeply embedded inside our existing client-facing and tax preparer-facing platform

• Influence the product roadmap and company strategy from day one

• Create custom mods for legacy softwares like Drake that don’t have APIs (yes, this will get funky)

• Automate manual tax prep tasks using AI models and data across Slack threads, Zoom transcripts, and messy document uploads

• Translate PDFs into structured CSVs with measurable accuracy — saving our team hundreds of hours

• Help define our engineering culture, tools, testing standards, and review process from scratch

What makes you a fit

• 4+ years of engineering experience (or equivalent — we care more about velocity and ownership than resume lines)

• You’ve built and shipped internal tools or ops automations at speed

• You’ve delivered in early‑stage environments where the roadmap is not clear

• You’ve turned real user feedback into features/products with a tight build‑measure‑learn loop

• You’re excited to work directly with tax professionals and solve ops problems with code

• Strong communicator — async, written, and live

Nice to haves

• You’ve deployed ML or LLM features in production (even basic prompt chaining is great)

• You’ve built for finance, fintech, or accounting workflows (e.g. QuickBooks, payroll, expense management)

• You’re comfortable working without a designer, or can sketch out usable UI yourself

• You enjoy getting creative with APIs, headless browser scripts, or building around systems that were not meant to be automated

Why You Might Like It Here

• Your work ships fast and hits production in days, not quarters.

• You’ll work with sharp peers who care deeply—no passengers.

• You’ll get to own entire features, not just a slice of a ticket.

• Mistakes are fixed, not buried. We learn and move on.

• You’ll never have to pretend to be “collaborating” just to look busy.

What we offer

• A meaningful equity stake in a company built to scale

• A profitable, well‑funded, fast‑moving environment with 0 layers of management

• A world‑class client base that expects — and pays for — premium service

• A fully remote team and twice‑yearly offsites

• The chance to build real, production‑grade software that your teammates use and love every day