Due: AI Due Diligence Platform
Frontend work on Due, an AI-powered SaaS that helps legal, tax and financial advisors run M&A due diligence, including Stripe billing and interactive relationship diagrams built with React Flow.
Overview
Due is a SaaS platform for due diligence. Advisors and companies share documents in a secure data room, track requests for information, and use AI to review legal and tax documents with no-code templates. The platform also covers supply chain due diligence, with compliance questionnaires and a shared knowledge base between organizations. I was first brought in to finish an in-progress integration between the product's website and its Stripe billing. The team then brought me back for frontend work on the web app and the marketing landing page, building from their Figma design system alongside their backend engineer and designer.
The business idea
Due diligence runs on unstructured documents: contracts, board minutes, shareholder deeds, supplier questionnaires. Reviewing them by hand is slow, and the important part is often the relationships between them: who owns what, which company controls which, which document binds whom. Due puts the documents, the team and the AI review in one place, so advisors spend their time on findings instead of paperwork.
Goals
- Finish the website's integration with the SaaS app and its Stripe billing, so customers can sign up and pay securely
- Turn complex due diligence findings into something a client can understand at a glance
- Build UI the team could reuse across the app and the landing page, faithful to the Figma design system
Tech stack
Key features
- Stripe payment integration connecting the marketing website to the SaaS app
- Interactive relationship diagrams that map the documents, people and organizations in a deal
- Custom React Flow node components for four entity types: document, person, group organization and standalone organization
- Click any entity to open a detail panel with its information
- Diagrams generated from each project's data in the app, plus a static showcase version on the landing page
- Landing page updates built to the refreshed brand palette in the DueTwo design system
Challenges & solutions
I joined mid-project to finish a Stripe integration another developer had started, in a codebase I hadn't seen.
Before writing code, I synced with the backend engineer on what was done and what was left, then finished the integration against the existing structure rather than reworking it, keeping the payment flow secure and tested end to end.
The design showed a diagram users could hover and click, but it turned out to be a static image. And every due diligence report has a different shape, so no fixed layout would work.
I scoped it as a generated system instead of a one-off page: a reusable set of React Flow node components, one per entity type, that the app arranges from each project's data. The landing page uses a separate static version of the same diagram, so marketing never depends on live data.
The client wanted a time estimate for a feature whose full range of cases nobody knew yet.
Rather than guess, I proposed building the foundation first and re-estimating once the real variety of report structures was visible, about a third of the way in. It gave the client a commitment I could stand behind instead of a number that would slip.
Lessons learned
- Check what a design actually is before estimating it. A mockup that looks interactive can hide most of the real work.
- When requirements are still forming, an honest phased estimate builds more trust than a confident wrong one.
- On a team codebase, finishing someone else's work cleanly matters more than rewriting it your way.
Want something like this built?
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