Personal Finance App Backend

WebsiteBackendServer

Nov 9

Personal Finance App Technical Design Diagram
Backend (boxed in white)

💾 Source Code

* the source code is not a working solution but a reference to help you get started

* Please note that Heroku is no longer free starting 11/28/2022. You can use Google Firebase as a free alternative.

API Server (Node.js)
- Use Node and Express for the backend API framework (JavaScript)
- Run on Google Firebase
- Other Web Framework Options
  - Python: Django/Flask
  - C#: ASP.NET Core
  - Java: Spring
  - PHP: Laravel
  - Ruby on Rails
Plaid (Financial Data Provider)
- Plaid Homepage
- Free for the first 100 financial accounts
- Plaid-Node - The official node.js client library
- Transactions API - expense tracking
- Balance API - net worth tracking
- Quick Start - documentation
Database (MongoDB)
- MongoDB Homepage
- NoSQL Database
  - You can use a relational database, but a NoSQL database is sufficient for small projects
- Mongoose JS - JavaScript-based Object Data Modeling (ODM) Library for MongoDB
- Other NoSQL Database Options
  - DynamoDB - Amazon AWS
  - CosmosDB - Microsoft Azure
- Other Relational Database Options
  - MySQL
  - PostgreSQL
Data Synchronizer (Background Job)
- Run on Google Firebase
- Run periodically on a set schedule (e.g. at least once every day, every 3 hours, etc.)
- Implement it using any programming language.
- Other Options
  - Run on Jenkins

* This guide assumes an intermediate level of JavaScript and coding in general

Use Node with Express for developing the backend.
Implement REST APIs for your expenses and balances.
- GET/POST/PUT/DELETE Expense API
- GET/POST/PUT/DELETE Balance API
Use their official node client Plaid-Node or implement your own.
Use MongooseJS for communicating with MongoDB.
Create at least two tables: transactions and balances.
Design your background job to periodically request financial data from Plaid and store them in your database.
Run the backend server and jobs on Google Firebase.
Bonus
Implement authentication and authorization (aka AuthN & AuthZ).
Design idempotent APIs.
Implement Unit Tests using Jest.

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