FullStack Developer

About HighLevel

HighLevel is an AI powered, all-in-one white-label sales & marketing platform that empowers agencies, entrepreneurs, and businesses to elevate their digital presence and drive growth. We are proud to support a global and growing community of over 2 million businesses, comprised of agencies, consultants, and businesses of all sizes and industries. HighLevel empowers users with all the tools needed to capture, nurture, and close new leads into repeat customers. As of mid 2025, HighLevel processes over 4 billion API hits and handles more than 2.5 billion message events every day. Our platform manages over 470 terabytes of data distributed across five databases, operates with a network of over 250 microservices, and supports over 1 million hostnames.

Our People

With over 1,500 team members across 15+ countries, we operate in a global, remote-first environment. We are building more than software; we are building a global community rooted in creativity, collaboration, and impact. We take pride in cultivating a culture where innovation thrives, ideas are celebrated, and people come first, no matter where they call home.

Our Impact

As of mid 2025, our platform powers over 1.5 billion messages, helps generate over 200 million leads, and facilitates over 20 million conversations for the more than 2 million businesses we serve each month. Behind those numbers are real people growing their companies, connecting with customers, and making their mark - and we get to help make that happen. Learn more about us on our YouTube Channel or Blog Posts

About the Role

We’re looking for a Senior Software Engineer to join our Agency Module and Billing Team, which powers the foundation of our Agency Ecosystem — enabling seamless onboarding, management, and monetisation experiences for HighLevel’s agencies and their clients.

Today, over 100K agencies run their businesses with HighLevel, collectively serving 2M+ businesses of all scales — primarily SMBs. The Company Module and Agency Billing systems are at the heart of this growth, helping agencies onboard faster, manage finances effortlessly, and scale their operations with reliability and transparency.

This team builds and scales key components like Agency Signup, Agency Billing, and the HighLevel Affiliate Program, all integrated into our whitelabeled platform that empowers businesses to deliver customised experiences under their own brand. These systems are critical to the growth and sustainability of HighLevel’s ecosystem — supporting thousands of agencies and their downstream customers with robust, scalable, and secure infrastructure.

As a Senior Software Engineer, you’ll play a pivotal role in designing and evolving these core systems. You’ll work on challenges across frontend and backend architecture, distributed systems, payment integrations, and multi-tenant SaaS design — ensuring reliability, scalability, and a seamless experience for agencies across web and mobile platforms.

You’ll collaborate closely with Product Managers, Designers, and other Engineers to deliver powerful and intuitive solutions that help agencies scale faster and manage their businesses effortlessly.

Responsibilities

• Own and contribute to architecture and development across Agency Module, Billing, and Affiliate systems, driving technical excellence across frontend and backend services.
• Design and implement robust backend APIs for subscription management, payments, invoicing, and affiliate tracking, using test-driven development and scalable distributed patterns (caching, messaging, queuing).
• Deliver performant frontend experiences for agency onboarding, billing dashboards, and affiliate management using modern frameworks and component-driven architecture with strong state management principles.
• Architect secure integrations with third-party payment gateways (e.g., Stripe) and internal microservices, ensuring accuracy, reliability, and compliance in all financial transactions.
• Implement and maintain observability, logging, and monitoring to ensure high availability and rapid incident resolution across critical billing and agency workflows.
• Champion platform security and compliance by enforcing best practices across authentication, authorization, data protection, and rate-limiting — ensuring the integrity of sensitive financial and user data.
• Leverage LLMs and AI-assisted tools to accelerate development, automate testing, refactoring, and documentation, while maintaining strong reliability guardrails.
• Collaborate cross-functionally with Product Managers, Designers, and other Engineering teams to ensure alignment between business goals and technical architecture.
• Participate in technical reviews, deep dives, and on-call rotations, fostering a culture of accountability, operational excellence, and continuous improvement.

Requirements

• 4+ years of hands-on software engineering experience building and scaling robust backend systems and high-performance frontend applications.
• Strong backend engineering and distributed system design skills, with hands-on experience in API development, data modeling, and systems architecture using Node.js (NestJS preferred), TypeScript, PostgreSQL, MongoDB, and Redis.
• Expertise in backend performance optimization, caching strategies, and event-driven architectures (e.g., Redis, Kafka, Pub/Sub).
• Familiar with modern frontend frameworks (React, Vue, Angular), advanced UI engineering patterns, and CSS libraries like Bootstrap or Tailwind CSS.
• Advanced experience with complex state management libraries (e.g., Redux, Vuex, MobX) and architectural design of large-scale application state.
• Proven track record of optimizing frontend performance and web vitals at scale, including experience with server-side rendering (SSR), edge, or hybrid rendering architectures.
• Familiarity with frontend and backend observability - including monitoring, tracing, error tracking, and performance profiling in production (e.g., Grafana, Prometheus, Sentry, PostHog).
• Strong understanding of security best practices across the full stack—including authentication, authorization, access control, secure data flow, and privacy compliance.
• Excellent communication and cross-functional collaboration skills, able to drive complex initiatives, lead technical discussions, and mentor junior engineers.

EEO Statement:

At HighLevel, we value diversity. In fact, we understand it makes our organisation stronger. We are committed to inclusive hiring/promotion practices that evaluate skill sets, abilities, and qualifications without regard to any characteristic unrelated to performing the job at the highest level. Our objective is to foster an environment where really talented employees from all walks of life can be their true and whole selves, cherished and welcomed for their differences while providing excellent service to our clients and learning from one another along the way! Reasonable accommodations may be made to enable individuals with disabilities to perform essential functions.

Role Overview

We are seeking a proficient Full Stack Developer with expertise in Java and React.js / Angular to join our dynamic team. The ideal candidate will be responsible for developing and maintaining scalable web applications, ensuring seamless integration between front-end and back-end systems.

Key Responsibilities

• Develop and maintain web applications using Java (Spring Boot) and React.js/ Angular.
• Design and implement RESTful APIs and microservices.
• Collaborate with cross-functional teams to define and deliver new features.
• Ensure application performance, scalability, and security.
• Participate in code reviews and maintain code quality standards.

Required Skills

• Strong proficiency in Java, Spring Boot, and React.js / Angular.
• Experience with RESTful APIs and microservices architecture.
• Familiarity with HTML, CSS, JavaScript, and modern front-end frameworks.
• Knowledge of version control systems like Git.
• Understanding of Agile development methodologies.

Position Overview:

We are seeking a highly skilled and experienced Senior Software Developer with a strong background in front end development to join our team. The ideal candidate will have over 6 years of experience in developing web and mobile applications using React JS, React Native, Angular, and other modern technologies. You will be responsible for leading complex projects, interacting with clients, and working in a team-oriented environment.

Key Responsibilities:

• Develop and maintain mobile and web applications using React JS and React Native. • Handle DevOps tasks using tools such as Filezilla and PuTTY. • Collaborate with clients to understand their requirements and translate them into technical solutions. • Lead the design, development, testing, and deployment of applications. • Integrate third-party services such as Google Maps, Firebase, and payment gateways. • Ensure responsive UI design and integration of RESTful APIs. • Work on hybrid mobile application development for both Android and iOS platforms. • Manage system design and development, including error handling, exception management, and logging. • Perform code reviews, testing, and release management. • Utilize tools like Git, Azure DevOps, and various IDEs for development and project management.

Required Qualifications:

• Primary Skills: React JS, React Native, Angular (4+ years of experience). • Experience with iOS (Xcode) and Android (Android Studio). • Programming Languages: JavaScript, TypeScript, HTML, CSS, PHP. • Frameworks and Libraries: Redux, jQuery, Ionic (3/4), AJAX. • Databases: MS SQL Server, MySQL. • Development Tools: Sublime, Dreamweaver, Visual Studio, Xcode. • Experience with design patterns, code reviews, and testing. • Domain booking, hosting, domain migration, cPanel, PhpMyAdmin. • Familiarity with Git and Azure DevOps. • Proven track record of working on complex projects and delivering high-quality solutions. • Experience in integrating third-party APIs and handling DevOps tasks. • Strong understanding of responsive UI design and lifecycle management.

Must have skills :

6+ Years Java, Spring - 4+ years, Node JS / React JS - 4+ years

Responsibilities:

Code, test and debug programs according to specifications.

Build new and modifying existing applications.

Develop software prototypes.

Write unit tests and functional tests (automation).

Perform manual tests.

Use tools to access data in datastore, version control systems, etc.

Practice Agile methodologies.

Frequently interface with other functional teams on all aspects of a feature or sub-system 

Full Stack Developers at The Seenit Co. are passionate about using technology to create an impact on the world they live in. At Seenit, you will get to collaborate with an accomplished team that loves solving real-world problems. You will get to work on cutting edge projects that will shape the next phase of growth for the global luxury industry.

Seenit’s suite of products enables the leading luxury retailers around the world to transform their customer experience and build loyal relationships with their customers. The apps allow retailers to make use of their existing infrastructure and resources to deliver a truly omnichannel experience in today's rapidly changing world of shopping.

We would welcome someone to the team who:

• Loves to write “clean”, well designed code to solve complex problems
• Can design, develop and test the core product software and databases to ensure strong optimization and functionality
• Is inclined to contribute in all phases of the development lifecycle and takes end to end ownership of the project
• Follows best industry practices
• Is excited to support others to succeed and shine in a collaborative team culture

• 1+ years of experience in developing web based applications
• Good knowledge of NoSQL databases, and query optimisations
• Experience with MongoDB, Express JS, React JS, Node JS
• Ability to pay attention to UI detail and develop amazing, non-standard user experiences
• Exposure to TypeScript will be plus

Your Day-to-Day Tasks Include: 

Ship product, independently and/or as part of a small team 

Collaborate with other engineers to build new features 

Debugging using dev consoles, firebug, firecookie, or any of your favorite tools. 

Help troubleshoot production issues and resolve critical customer facing issues Provide top-notch support to our customers 

You Should Have: 

A strong body of prior front end work, including significant projects written in JavaScript. Mastery of JavaScript; expertise in most of the following technologies, and proficiency in all of them: jQuery, CSS, HTML5, AJAX. 

Deep understanding of closures, prototypal inheritance, DOM manipulation, HTTP, web security, cross browser compatibility challenges. 

Strong Experience with NodeJS and Express JS. 

Hands-on with a code management system like GIT, SVN. 

Experience with NoSQL databases, preferably CouchDB or CouchBase. 

Good to have: Experience with ReactJS and Typescript.