Senior Frontend Developer Jobs in Haslet, TX (NOW HIRING)

Position Summary

Multi-Bank Securities, Inc. has a direct hire opportunity for a Senior .NET Web Developer to join our team in Southfield, Michigan. This role supports and enhances a large, mission-critical financial web platform built over many years using a mix of technologies, including ASP.NET Web Forms, C#/.NET, ASP.NET Web API, SQL Server, AngularJS, jQuery, jQuery UI, Bootstrap, Highcharts, and selected modern front-end patterns.

The right candidate is comfortable working in a mature enterprise application where different areas of the site use different frameworks and patterns. You will spend much of your time supporting, debugging, improving, and incrementally modernizing existing application areas, while also applying strong UI/UX judgment to make workflows clearer, more consistent, and easier to use. This role is best suited for a senior developer who enjoys owning work end to end, researching unfamiliar areas independently, and collaborating with business and technical teams to deliver safe, practical improvements.

We are looking for someone who can work effectively in legacy code, understand existing business behavior, ask the right questions when requirements are vague, and make safe improvements without pushing unnecessary rewrites. This role is ideal for a developer who respects the value of an existing production platform while helping move it toward a cleaner, more maintainable future.

Responsibilities

• Support, enhance, and modernize a large ASP.NET-based financial web platform with a mix of ASP.NET Web Forms, AngularJS, jQuery, C#/.NET, ASP.NET Web API, and SQL Server.

• Work primarily within existing application areas while identifying safe opportunities to improve maintainability, usability, performance, and reliability.

• Debug issues across ASP.NET Web Forms, view state, postbacks, user controls, master pages, code-behind, session state, JavaScript, AJAX, browser behavior, SQL, IIS, and deployment environments.

• Reproduce and troubleshoot issues locally using Visual Studio, browser developer tools, SQL tools, logs, Azure DevOps work items, and source control history.

• Use Azure DevOps with Team Foundation Version Control (TFVC) for the main website codebase and Git where used by supporting applications and services.

• Translate incomplete or vague user stories into clear questions, expected behavior, edge cases, and implementation plans.

• Research unfamiliar areas of the application independently by tracing code, reviewing existing behavior, validating assumptions, and asking informed questions.

• Improve UI/UX within existing screens and workflows, especially data-heavy financial areas involving forms, grids, search, filtering, sorting, paging, exports, charts, account workflows, and order-related interactions.

• Create wireframes, mockups, or prototypes when useful to clarify user flows, screen layout, or stakeholder expectations.

• Implement user interface changes directly in legacy and mixed front-end technologies, including Web Forms markup, JavaScript, jQuery, AngularJS, Bootstrap, CSS, and existing component patterns.

• Collaborate with business users, product owners, QA, support, and other developers to deliver reliable incremental changes.

• Document complex, fragile, or business-critical areas so future support and development work is easier.

• Participate in code reviews, release planning, defect resolution, and modernization discussions.

Required Qualifications

• Bachelor's degree in Computer Science, Software Engineering, a related field, or equivalent practical experience.

• Five or more years of professional experience building, maintaining, or enhancing production web applications.

• Strong hands-on experience with C#, .NET, and ASP.NET web applications.

• Practical experience maintaining or enhancing ASP.NET Web Forms applications.

• Understanding of Web Forms concepts such as view state, postbacks, user controls, master pages, page life cycle, server controls, code-behind, and session state.

• Strong JavaScript debugging skills, including legacy JavaScript, jQuery, DOM behavior, event handling, AJAX calls, browser developer tools, and asynchronous behavior.

• Experience with AngularJS 1.x or demonstrated ability to support and debug AngularJS legacy code.

• Ability to debug locally in Visual Studio and browser developer tools without relying entirely on other developers.

• Experience with enterprise source control and work tracking systems, preferably Azure DevOps with Team Foundation Version Control (TFVC).

• Solid SQL Server skills, including reading stored procedures, troubleshooting queries, understanding joins, and validating data-driven issues.

• Ability to work safely in a large, mixed-technology application where small changes can have broad side effects.

• Ability to clarify vague requirements by asking good questions, researching existing behavior, and identifying practical options.

• Strong written and verbal communication skills.

• Strong attention to detail, especially when working on business-critical financial workflows.

Required UI/UX Strengths

• Ability to improve existing user interfaces without requiring a full redesign.

• Strong judgment around usability, workflow efficiency, validation, error states, consistency, accessibility, and screen layout.

• Ability to balance technical constraints with user experience improvements.

• Comfort working directly with stakeholders to understand what users are trying to accomplish.

• Ability to create wireframes, mockups, or prototypes when needed, while also being comfortable implementing UI changes directly in the application.

• Practical understanding of responsive design, cross-browser behavior, and accessibility considerations.

Preferred Qualifications

• Experience with Azure DevOps TFVC, including changesets, shelvesets, branching, merging, and work item linking.

• Experience with Git in supporting applications, services, or newer repositories.

• Experience with ASP.NET Web API, REST services, authentication/authorization, caching, middleware, and service integrations.

• Experience with IIS, application pools, cookies, session behavior, browser compatibility, and deployment troubleshooting.

• Experience with Octopus Deploy or similar deployment tooling.

• Experience with Highcharts, Bootstrap, jQuery UI, Webpack, TypeScript, or modern Angular.

• Experience modernizing legacy applications incrementally with minimal production risk.

• Experience improving logging, diagnostics, testability, and local development setup.

• Experience with Figma, Adobe XD, Sketch, or similar design/prototyping tools.

• Financial services, brokerage, trading, banking, fixed income, or other regulated-industry experience is helpful but not required.

• Experience using modern AI-assisted development tools responsibly to improve productivity, code understanding, testing, or documentation.

Current Technical Environment

• ASP.NET Web Forms, C#/.NET, ASP.NET Web API

• SQL Server and stored procedures

• AngularJS 1.x and selected Angular areas

• jQuery, jQuery UI, Bootstrap, Highcharts

• Legacy JavaScript, ES5, CommonJS-style modules, IIFEs

• Visual Studio

• Azure DevOps with TFVC for the main website

• Git for selected applications and services

• IIS-hosted applications

• Webpack v3 legacy bundles

• Octopus Deploy

How Success Will Be Measured

• Ability to independently reproduce, debug, and resolve issues across ASP.NET Web Forms, JavaScript, C#, SQL, and browser behavior.

• Safe improvements to existing application areas without destabilizing unrelated functionality.

• Clearer and more usable workflows on key financial screens.

• Better handling of vague user stories through research, thoughtful questions, and practical implementation plans.

• Reduced fragility in legacy areas through incremental refactoring, documentation, and clearer boundaries.

• Successful modernization steps delivered with minimal disruption to business users.

• Faster onboarding and support through improved documentation and knowledge sharing.

Candidate Profile

The ideal candidate is a senior developer who has worked in real-world enterprise systems and is not discouraged by older technology, mixed patterns, or imperfect code. This person can support today's application, debug difficult issues, improve user experience, and help the team modernize gradually.

This role is best for someone who enjoys solving practical business problems, learning existing systems deeply, asking good questions, and making careful improvements that reduce risk over time.

Company Overview:
Multi-Bank Securities, Inc. (MBS) is an independent investment firm that specializes in the sales, trading and underwriting of institutional, fixed-income securities. As an independent broker-dealer, MBS has been serving institutional investors across the U.S. since 1988. MBS is a veteran-owned business and an approved underwriter of Fannie Mae Securities through their ACCESS® program. Multi-Bank Securities, Inc. is registered with the SEC and MSRB and Member of FINRA and SIPC. MBS has an impeccable FINRA customer compliance record. In keeping with our commitment to hire veterans, we encourage veterans to apply for employment opportunities.