[Freelens] Add a feature for real-time tax calculation updates

Hey r/SaaS, I'm a solo dev who's been freelancing in France for a few years. The French tax system for independents is absurdly complex — 7 legal statuses, each with different social contribution rates, income tax brackets, corporate tax thresholds, VAT rules, and retirement implications. Most freelancers have no idea what they actually keep after taxes. I got frustrated with spreadsheets and built a tool to figure it out. It turned into a full product: **Freelens** — a financial copilot for French freelancers. **What it does:** * Simulates net income across all 7 French legal statuses side by side * Projects revenue month by month with seasonality, vacation days, and client portfolio * Fiscal calendar with every tax deadline and estimated amounts to provision * Holding company optimizer (parent/subsidiary tax structures) * Invoice & quote generation with PDF export * Client pipeline (lead → quote → invoice → paid lifecycle) **Tech stack:** * Next.js 15 (App Router) + TypeScript + Tailwind v4 * The entire tax engine runs client-side — \~400 lines of pure math, no API calls for calculations * Zustand for state, Prisma + Supabase for persistence * Stripe for subscriptions (9€/mo or 79€/yr) **What's working:** * The "aha moment" is instant — users plug in their daily rate and see what they actually keep. Most are shocked. * Comparison between statuses drives conversions — freelancers about to incorporate use it to pick between SASU and EURL * The fiscal calendar is sticky — people come back monthly to check their upcoming tax deadlines **What I'm struggling with:** * Acquisition. The product is niche (French freelancers only, \~1M addressable market). SEO is slow, LinkedIn organic is my best channel so far. * Churn on the free tier — people simulate once and leave. Working on a cash flow forecast feature to create daily engagement. * Pricing — 9€/mo feels right for the value but hard to justify vs a free spreadsheet. Considering making the simulator fully free and gating only invoicing + holding optimizer. **Metrics (honest):** * Solo dev, launched 3 months ago * MRR: still early, mostly trial users converting * Stack cost: \~30€/mo (Supabase free tier + Vercel Pro) Would love feedback from other SaaS founders: 1. For a niche vertical tool like this, did you find a channel that worked beyond content/SEO? 2. Anyone else building for the French/European market? The regulatory complexity is a moat but also limits TAM. 3. Free tier strategy — should I give away more to build habit, or gate early to filter serious users? Happy to share the tax engine logic or discuss the technical architecture if anyone's curious. Site: [freelens.io](http://freelens.io)