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Joan A.
Joan A.

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I built an AI-powered investment portfolio tracker for Spanish investors — here's what I learned

Originally published on finasset.app | Cross-posted to dev.to / Medium


After years of managing my investments with Excel spreadsheets and juggling between multiple broker dashboards, I built Finasset — an AI-powered portfolio tracker designed specifically for Spanish investors.

Here's what I learned building it, and why I think the market needed something different.

The Problem: Spanish investors are underserved

The big portfolio trackers — getquin, Finary, Sharesight — are excellent, but they're built primarily for German, French, or English-speaking markets.

Spanish investors have specific needs that these tools don't address:

1. IRPF (Spanish income tax) complexity

Spain's capital gains tax system has nuances that generic tools miss:

  • Different tax brackets for savings income (19%-28%)
  • Complex withholding tax recovery from foreign dividends
  • Specific rules for compensation of losses vs gains

2. Spanish broker ecosystem

Popular brokers in Spain (Myinvestor, Renta 4, BBVA Broker) don't integrate with most international trackers. Manual entry is the only option.

3. Language barrier

Most Spanish individual investors aren't comfortable with English-only tools. The community around investing in Spain has exploded in recent years, but the tooling hasn't kept up.

The Solution: Finasset

I built Finasset to solve these specific problems:

AI Analysis with Vera

Vera is Finasset's AI analyst. She analyzes your entire portfolio and generates:

  • A Health Score (0-100) that rates your portfolio's overall quality
  • Diversification analysis: sector, geographic, and asset type distribution
  • Risk assessment: volatility, correlation between positions, stress scenarios (2008, COVID, 2022)
  • Fee optimization: identifies positions with high costs and suggests alternatives
  • Concrete recommendations: "Reduce VWCE concentration to max 70%. Adding EMIM could add +17 points to your score"

Dividend Tracking

Beyond basic dividend tracking, Finasset calculates:

  • Yield on Cost (not current yield — what you're actually earning based on your purchase price)
  • DRIP projections: Future Value at 10, 25, and 40 years with and without dividend reinvestment
  • Annual payment calendar: Visual calendar showing when each position pays
  • Projected annual income: Total passive income from your current portfolio

Tax Summary (IRPF)

The feature I'm most proud of: a complete IRPF summary exportable as PDF, covering:

  • Realized capital gains and losses
  • Dividend income with source country
  • Foreign withholding taxes for double taxation treaty recovery
  • Net taxable base estimation

Multi-broker support

Finasset works with any broker via manual entry. We're building CSV import for major Spanish brokers.

Technical Stack (for the curious devs)

  • Frontend: PWA (Progressive Web App) — works on iOS, Android, and desktop browsers
  • Backend: Supabase (PostgreSQL + Auth)
  • Price data: EODHD, Yahoo Finance, TwelveData APIs
  • AI: Claude API for Vera's analysis
  • Hosting: Cloudflare

The PWA approach was a deliberate choice — one codebase for mobile and desktop, no app store friction, and instant updates without review delays.

What's Next

We're working on:

  • CSV import from major Spanish brokers (DEGIRO, Trade Republic)
  • Enhanced tax optimization suggestions
  • Community features (anonymized portfolio sharing, ranking)
  • API for developers

Try it free

Finasset has a generous free plan: unlimited portfolio positions, real-time prices, dividend tracking, and 5 AI analyses per week.

Pro plan (€4.99/month) unlocks unlimited AI, PDF exports, price alerts, and priority support.

Try Finasset free at finasset.app


Have you built something for a specific geographic market? What challenges did you face with localization vs. building for a global audience? I'd love to hear your experience.

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