Founding Product Engineer

About the role

Cranston is building the AI back office for accounting firms, combining the judgment of experienced operators with the leverage of AI agents and reliable software.

We automate the most complex manual workflows inside CPA firms: tax preparation, bookkeeping, document collection, cleanup, review, close, and client operations.

Cranston is already deployed with accounting firms across the country, helping them serve more clients, reduce bottlenecks, and give their best people time back for higher-value work.

You will work across product, design, engineering, and implementation. Some days that means mapping how tax packages move through a firm. Other days it means building a review workflow, designing an agent loop, tightening data models, or debugging why a customer workflow failed in production.

This is a product engineering role for someone who wants to build the system, not just spec it. You will turn what we learn from firms into durable product: interfaces, automations, review loops, workflow primitives, data models, and agent behavior that work across customers.

Cranston is vertically integrated across software, AI agents, and managed back‑office operations. That makes the problems unusually concrete: if the product is wrong, the work breaks. If the product is right, firms can take on more clients without adding headcount.

Why Cranston

• Cranston was founded by Sean O'Bannon and Max Minsker to rebuild the accounting firm back office from the ground up.

• Sean previously built ERP and ML systems at ReMatter and Databricks, seeing how much labor still sits on top of even the best systems of record. Max ran an accounting firm that filed 10,000+ tax returns and saw the same problem from inside the work itself: firms losing their best hours to document chasing, data entry, reconciliations, cleanup, and handoffs.

• Our view is that the next generation of accounting firms will not run on bigger offshore teams or more disconnected point solutions. They will run on AI agents that can understand firm context, do the repetitive prep work, and leave the judgment calls to experienced accounting professionals.

• We are rebuilding the back office for one of the most important professional services industries in the country.

• Accounting firms are under structural pressure: talent shortages, rising client expectations, and more work than their teams can absorb.

• AI agents can finally change the operating model of the firm, not just make another dashboard or point solution.

• 5M raised from top tier investors.

• Dozens of customers, with revenue growing quickly.

• A small team where one strong engineer can own major product surfaces end to end.

What you will do

• Own core product workflows for tax prep, tax review, bookkeeping, client requests, and practice‑management operations.

• Design and build product abstractions that turn messy accounting work into repeatable, reviewable systems.

• Use Cranston's internal agent platform to move from product context to working software quickly, then inspect the result until it is right.

• Build interfaces, workflow states, data models, and agent behavior that hold up in live customer usage.

• Codify repeatable patterns from customer deployments back into the main product.

• Use the product yourself, inspect logs and data when needed, notice what is wrong, and push until the details are right.

Your first 30 days

• Learn how CPA firms move work from source documents to reviewed tax packages, books, and client follow‑ups.

• Shadow existing Cranston workflows and identify places where better product behavior would remove real manual work.

• Pick workflows and turn them into a concrete product plan: inputs, user‑facing states, edge cases, success criteria, and verification steps.

• Drive an AI‑agent implementation loop from product plan to working feature.

• Test the workflow yourself against real or realistic data, fix the rough edges, and help ship it into a live customer or internal operator workflow.

Who we are looking for

• You have strong programming skills and have shipped production applications, serious internal tools, or customer‑facing automation.

• You have high agency and can navigate ambiguity in messy customer environments where the problem is not handed to you cleanly.

• You have an ownership mentality and are willing to do whatever it takes to make something work.

• You have good communication skills to explain technical tradeoffs and earn trust with non‑technical stakeholders.

• You are comfortable using AI coding agents as your main implementation tool and holding their output to a high bar.

Skills

AI Agents · React · Swift · TypeScript · Docker · PostgreSQL

Bonus points

• Experience in accounting, finance, tax, audit, professional services, or another workflow‑heavy enterprise vertical.

• Previous founder experience or meaningful ownership at an early‑stage startup.