Fondo local dev loop

Fondo Local Dev Loop

Overview

Local development workflow for Fondo startup tax and bookkeeping integration. Provides a fast feedback loop using CSV exports and mock financial data so you can build dashboards, R&D credit calculators, and burn-rate tools without waiting on live Fondo reports. Toggle between mock mode for rapid iteration and real export parsing for production validation.

Environment Setup

cp .env.example .env
# Set your credentials:
# FONDO_API_KEY=fondo_xxxxxxxxxxxx
# FONDO_EXPORT_DIR=./exports
# MOCK_MODE=true
npm install express csv-parse dotenv tsx typescript @types/node
npm install -D vitest supertest
mkdir -p exports

Dev Server

// src/dev/server.ts
import express from "express";
const app = express();
app.use(express.json());
const MOCK = process.env.MOCK_MODE === "true";
if (MOCK) {
  const { mountMockRoutes } = require("./mocks");
  mountMockRoutes(app);
} else {
  const { mountExportRoutes } = require("./export-parser");
  mountExportRoutes(app, process.env.FONDO_EXPORT_DIR!);
}
app.listen(3002, () => console.log(`Fondo dev server on :3002 [mock=${MOCK}]`));

Mock Mode

// src/dev/mocks.ts — realistic startup financial data
export function mountMockRoutes(app: any) {
  app.get("/api/transactions", (_req: any, res: any) => res.json([
    { date: "2025-03-01", description: "AWS Infrastructure", amount: -4200, category: "Cloud Hosting", account: "Operating", isRnD: true },
    { date: "2025-03-05", description: "Engineer Salary", amount: -12500, category: "Payroll", account: "Operating", isRnD: true },
    { date: "2025-03-10", description: "Stripe Revenue", amount: 8750, category: "Revenue", account: "Income", isRnD: false },
  ]));
  app.get("/api/reports/pnl", (_req: any, res: any) => res.json({
    period: "2025-Q1", revenue: 26250, expenses: 50100, netIncome: -23850,
  }));
  app.get("/api/reports/rnd-summary", (_req: any, res: any) => res.json({
    totalQualified: 38500, categories: ["Cloud Hosting", "Payroll", "Software Tools"],
  }));
}

Testing Workflow

npm run dev:mock &                    # Start mock server in background
npm run test                          # Unit tests with vitest
npm run test -- --watch               # Watch mode for rapid iteration
MOCK_MODE=false npm run test:integration  # Test against real Fondo CSV exports

Debug Tips

• Place sample CSVs in exports/ to test parsing without Fondo dashboard access
• Validate CSV column headers match Fondo's export format (Date, Description, Amount, Category, Account, R&D Qualified)
• Use --verbose flag with the parser to log skipped rows and type coercion warnings
• Check for locale-specific number formats ($1,234.56 vs 1234.56) in Amount column

Error Handling

Issue	Cause	Fix
CSV parse error	Malformed export file	Re-export from Fondo with UTF-8 encoding
NaN in amount	Currency symbols in Amount column	Strip $ and , before parseFloat
Missing R&D column	Older export format	Use Fondo's updated report template
ENOENT exports/	Export directory missing	Run mkdir -p exports
Empty dataset	Date range has no transactions	Widen the date range in Fondo dashboard

Resources

• Fondo Dashboard
• csv-parse docs

Next Steps

See fondo-debug-bundle.