Solving User Authorization Issues for Deposits in a Fintech Project
Published: 2024-06-28 15:27:24

The fintech world is constantly changing and securing financial transactions is of utmost importance. Recently, I faced a particularly challenging problem in a fintech project I was working on. The task was to ensure that only authorized users could make deposits into their accounts. Despite using JSON Web Tokens (JWT) for authentication and authorization, I ran into some significant roadblocks. Here's a personal account of how I tackled this issue and finally found a solution.

Imagine this: You’ve done a decent job building a fintech application using Node.js, Express, MongoDB, and JWT. You’re feeling pretty good about it, but then you realize that your user authorization isn't working as expected. Valid tokens aren’t being recognized, and worse, invalid tokens are slipping through the cracks. This isn’t just a bug; it’s a security nightmare waiting to happen. Frustration sets in as you try to figure out what went wrong.

**These Are The Steps I Followed To Resolve The Issue**
**Step 1: Identifying the Root Cause**
First, I needed to relax my mind and carefully identify why the JWT authorization was failing. This meant digging deep into the potential issues and these where the questions I asked myself:

- Was the token generation process flawed?

- Were tokens being stored and retrieved correctly?

- Was the middleware for token verification functioning as intended?

- Were the authorization checks in the deposit route properly configured?

**Step 2: Correcting JWT Generation**

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/98g54hsm35ji8ipe5dap.png)

Making sure to use a strong secret key and including necessary user information in the token payload was the first step toward regaining control.

**Step 3: Storing and Retrieving Tokens**
Next, I ensured that tokens were correctly sent to the client and stored securely. Tokens should typically be stored in HTTP-only cookies or local storage on the client side. Here's an example of how to set an HTTP-only cookie in Express:

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/i6i2xbj9lf07vpkho0mu.png)

**Step 4: Implementing Token Verification Middleware**
The next step was to verify tokens for protected routes. I implemented middleware to check if the token provided in the request header was valid. Here's how I did it:

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/xz5e55mcdwrplo8pf52a.png)

**Step 5: Implementing Authorization in the Deposit Route**
With the token verification in place, I added the authorization check in the deposit route. This ensured that only authenticated users could make deposits. Here’s the implementation:


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/3obr61rsbdxyyd5k2n98.png)

**Step 6: Testing the Implementation**
Finally, after implementing these steps, I tested the authorization flow rigorously:

- Verified that valid tokens allowed access to the deposit route.

- Ensured that invalid or expired tokens were correctly rejected.

- Checked that unauthorized users couldn't make deposits.

When I saw everything working perfectly, it was a moment of great relief. The frustration and uncertainty I felt earlier were replaced with satisfaction and fulfilment. It was a reminder that persistence pays off and that every problem, no matter how daunting, has a solution if approached methodically.

Reflecting on this challenging yet rewarding experience, I eagerly anticipate the journey ahead with the HNG Internship. Known for pushing interns to their limits and fostering growth, this program offers invaluable real-world experience. My aim in joining HNG Internship is to refine my skills, engage in impactful projects, and learn from industry leaders.

Beyond coding, HNG promotes collaboration, innovation, and pushing boundaries. It's a chance to contribute to meaningful projects that drive change. Whether you're seeking talented developers or aiming to enhance your skills, explore HNG's hiring platform https://hng.tech/hire. Discover top talent ready to tackle complex challenges at https://hng.tech/internship, or Premium opportunities https://hng.tech/premium. Join us in shaping the future of tech!