Building Secure Financial Dashboards Using Blazor WebAssembly

“The cost of failing at data security isn’t just in dollars, it’s in lost trust, business, and sometimes, lawsuits.”

If you spend time with folks in finance, you’ll hear one worry come up over and over: “Can we trust our data to stay private?” 

As more financial tools and dashboards move online, security isn’t just a checkbox—it's at the center of every conversation.

Just to give you a picture, global spending on information security is forecast to reach over $211 billion in 2025. Most of this budget is going into strategies to keep sensitive data safe, protect business reputations, and prevent the financial chaos that comes with data breaches. For financial dashboards, which often display very private data, this means one misstep could lead to severe consequences.

And here’s another number that really makes you sit up: the dashboard software market is expected to grow from $6 billion in 2024 to $6.88 billion in 2025. That’s a lot of dashboards—many holding sensitive account balances, performance metrics, and audit trails.

All these numbers highlight something clear: if you’re going to build a financial dashboard today, you’ve got to care about security from the first sketch on your whiteboard.

What is Blazor WebAssembly?

Before diving into the how-to, let’s get on the same page about Blazor WebAssembly (Wasm). I’ve noticed a lot of confusion here, especially if you come from a background in JavaScript frameworks.

Blazor WebAssembly is a tool from Microsoft for building the part of websites that users see and interact with.

It's built on C# and .NET but runs right in your browser—no plugins, just pure web standards. Here’s the trick: Blazor compiles C# code into a format (WebAssembly) that browsers can understand. So, you get rich, interactive apps in the browser with the safety and features of .NET.

• Why pick Blazor WebAssembly?

Blazor is catching attention. As of March 2025, over 34,000 active websites use Blazor, and it consistently ranks among the top choices for WASM-powered web apps. Even with its “niche” tag, it’s growing steadily because teams want tools that balance convenience and safety.

Why Security is a Big Deal for Financial Dashboards

You might wonder if people are just being paranoid. But let’s look at the facts:

• Global Data Security market size is expected to reach $7.79 billion by 2025.

• Over $211 billion will be spent worldwide this year on defending information.

• One breach in a financial dashboard isn’t just embarrassing—it can turn into fines, lawsuits, and loss of business.

• Regulatory compliance (think GDPR, PCI DSS, SOX) is strict, so falling short isn’t an option.

The main threats are:

• Unauthorized access to confidential numbers.

• Manipulation of financial reports.

• Leaking customer identity or payment details.

• Service outages triggered by attacks.

If you, like me, have had to explain a data breach to a board or a client, you know the sinking feeling well. So, let’s explore how to prevent it.

Security Risks Unique to Blazor WebAssembly

You may hear some people ask, “If Blazor runs in the browser, isn’t everything exposed?” It’s a fair question.

Blazor WebAssembly faces unique risks:

• All client-side code can be viewed and tinkered with (just like JavaScript).

• Sensitive logic (like encryption) shouldn’t run only on the client—it’s easy to reverse-engineer.

• If you don’t use HTTPS, data between client and server can be snooped.

• Bad session management can leave financial data open to hijacking.

So, when building dashboards with Blazor WebAssembly, the rule is simple: treat every client-side action as public. Never trust the browser with secrets. Always validate on the server.

Layered Approach to Security: How I’d Do It

Think of security in layers. If one falls, others should catch the problem. Here’s how I guide friends and clients:

1. Only Show What Users Should See

Role-based access control (RBAC) is step one. It means you check who’s logged in, and only show data they’re allowed to view. In Blazor, this is usually hooked up to authentication tools like ASP.NET Identity or Azure AD.

• Never trust the browser alone to hide fields.

• Place these checks in both your client and your server APIs.

2. Always Use HTTPS

If you skip HTTPS, anyone on the network can spy on your data. Always, always require HTTPS for dashboards. Use security headers and HSTS (HTTP Strict Transport Security) as backup.

3. Validate All Inputs on the Server

Don’t trust any number, string, or query the browser sends over. Malicious users can easily fake or tamper with data in transit. Always check, filter, and sanitize inputs on the server before writing anything to your database or showing it in a report.

4. Store Secrets Server-Side

API keys, database passwords, bank credentials—none of these should ever touch the browser. Use environment variables and secure vaults on the server side.

5. Protect Against Cross-Site Scripting (XSS)

If you echo back text submitted by users, use sanitization libraries. Always escape output in Blazor components.

6. Watch Out for Cross-Site Request Forgery (CSRF)

Finance apps often use anti-forgery tokens in requests. Double-check that your APIs check for these tokens—especially for money transfers or data changes.

7. Strong Session and Token Management

Keep tokens short-lived, use refresh tokens carefully, and never let sensitive data leak into URLs or local storage.

Best Practices: Secure Dashboard Design

If you’re building a dashboard, you might love to jump into charts and tables. But here are the core ideas for keeping things safe:

Keep UI Clean, But Don’t Over-Simplify

Show only the info users need. Don’t display financial details in lists or exports unless required.

Carefully Design Data Exports

The option to export financial data to Excel or PDF can be risky. Make sure:

• You track who processes what export.

• Exports are encrypted and permissions-checked.

Granular Audit Trails

Every dashboard should keep logs that answer:

• Who saw or downloaded what?

• Who edited or approved which numbers?

• When did these actions happen?

This isn’t just helpful for tracking down issues. It’s also vital for compliance.

Use Modern Identity Providers

Blazor works well with standards like OAuth2, OpenID Connect, Azure Active Directory, or Okta. This means users can log in safely, with multi-factor authentication options.

Frequent Security Testing

Run automatic scans with tools like OWASP ZAP, and ask for periodic “penetration testing” by security experts. Set reminders to update dependencies—one old library can open the door to hackers.

Step-by-Step: Building a Secure Financial Dashboard in Blazor WebAssembly

Here’s how I’d guide a friend through a new dashboard project, one step at a time:

1. Set Up the Project

• Install the latest .NET SDK.

• Create a new Blazor WebAssembly project with the “ASP.NET Core Hosted” option (so you get a back-end too).

2. Secure Authentication First

• Use ASP.NET Core Identity or connect to a third-party provider.

• Make sure registration, sign-in, and password reset all require strong passwords and multi-factor authentication (MFA).

3. Build the Dashboard UI

• Design components for charts, tables, filters, and summaries.

• Avoid exposing raw data in the client—fetch only what’s needed.

4. Protect Your APIs

• Mark all API endpoints [Authorize].

• Validate permissions on every call.

• Sanitize all user input.

5. Encrypt Sensitive Data

• Use encryption both for stored data (at rest) and when sending over the network (in transit).

• Never store confidential info in Blazor's client-side state.

6. Implement Logging and Monitoring

• Use Application Insights or a similar logging system to track access and errors.

• Send alerts for suspicious activity, like failed logins or massive data exports.

7. Test for Vulnerabilities

• Run static code analysis.

• Check for common issues

• Schedule regular audits.

Real-World Scenarios and Solutions

Let’s walk through a few everyday issues I’ve seen pop up in financial dashboard projects, and how you can solve them.

1. Problem: Sensitive Data in the Browser

A team once built a dashboard where monthly salary payouts were embedded in the client-side code (whoops). Anyone with Chrome dev tools could see pay rates for every employee.

Solution:

• Fetch sensitive data from the server only as needed.

• Consider returning “summary” data for graphs, and expose details only to admins.

• Scramble or hash IDs—never expose actual bank or account numbers.

2. Problem: Open APIs with No Authentication

An old finance portal’s API served statement PDFs with no login required. Attackers found account numbers and downloaded thousands of confidential docs.

Solution:

• Put all APIs behind authentication and authorization.

• Rate-limit access and log every download.

3. Problem: Data Export Gone Wild

A dashboard let users export “all company transactions ever.” One disgruntled employee downloaded years of history before leaving.

Solution:

• Limit exports to role-based access.

• Alert managers for unusual export activity.

Usability vs. Security: Finding the Balance

I hear it a lot: “Don’t make it so secure that no one can use it.” Fair point. Good security should never make users feel punished.

Some tips:

• Use single sign-on (SSO) to avoid password fatigue.

• Offer role-based dashboards: give execs the broad view, staff the details.

• Allow users to report errors or ask for access when needed, through a clear support channel.

If your dashboard feels too locked down, you risk people bypassing rules or copying sensitive data into personal spreadsheets.

Keeping Up with Compliance

Data rules aren’t the same everywhere. Financial dashboards often need to obey strict laws like:

• GDPR: For users in the EU. Data collecting and storage rules are tough.

• SOX: U.S. regulation to ensure financial transparency.

• PCI DSS: If you handle payment data.

Blazor WebAssembly apps can fit into these rules, but only if you:

• Let users see (and control) their stored data.

• Encrypt records at rest and in transit.

• Store logs for required periods.

If you work with a Blazor Development Company, make sure they’re well-versed in these standards—mistakes can be expensive.

Advanced Tips: Going Beyond the Basics

Use Content Security Policy (CSP) Headers

CSP headers help block XSS attacks by telling browsers which scripts are allowed. Set them up in your server.

Track Data Flows

Use data flow diagrams to map out what data moves where—especially when you bring together different APIs and vendors.

Minimal Data Storage on the Client

Stick to storing only things like JWT access tokens, and clear them out on sign-off. Never persist financial data in local storage.

Secure Real-Time Updates

Financial dashboards often use “push” updates, like SignalR or WebSockets. Always authenticate every connection and never send confidential info over insecure channels.

Plan for Questions

Financial auditors will often ask: “Who accessed what, when, and why?” Design your dashboards to answer these questions with detailed logs and permission tracking.

The Future of Financial Dashboard Security

I like to keep an eye out for the next changes in the field. Industry analysts expect:

• More dashboards will use AI for risk detection and prediction.

• Quantum computing may soon change encryption standards for finance.

• Real-time compliance checks will get baked into dashboards.

As hackers get smarter, so do defenders. The dashboard of tomorrow will have to adapt quickly, with layers of controls monitored by both humans and AI.

Closing Thoughts

If you’re starting a project in Blazor WebAssembly, don’t worry if security feels intimidating. Pay attention to roles, permissions, and how your app processes data. Keep things simple where you can, and always ask: “If I were a hacker, could I get anything valuable here?”

From what I’ve seen, the most secure dashboards are the ones that keep asking this question—not just at project kickoff, but every time a line of code changes. 

Your users and your business are counting on it, whether you realize it or not. And hey, if you ever feel lost, reach out to Zenesys Solutions Inc for assistance.