MEAN Stack Developer

Senior Full Stack Developer

Level: Senior

Experience: 8–10 years

Function: Full Stack Engineering (Frontend + Backend)

Role Overview

As Senior Full Stack Developer, you will own both the frontend and backend of the platform —

building the agent-builder experience users interact with, and the services behind it. You will

turn a complex agent platform into an intuitive product where users can build, deploy, and run

agents with ease

.

Key Responsibilities

• Build the agent-builder interface — visual composition, configuration, testing, and

monitoring of agents.

• Develop responsive, high-performance frontend applications with a clean, reusable

component architecture.

• Design and build the backend APIs and services that power agent creation, deployment,

and runtime.

• Implement real-time features — streaming agent outputs, live execution logs, and run

traces.

• Integrate the frontend and backend with the AI / ML layer, third-party tools, connectors,

and authentication providers.

• Own data models, API contracts, and end-to-end feature delivery from design through to

production.

• Maintain quality through testing, code review, performance tuning, and sound engineering

practices.

Required Skills & Experience

• 8–10 years of full-stack development experience, ideally on SaaS or developer / platform

products.

• Hands-on experience with agent-builder / Agent OS platforms — products where users

build, deploy, and run AI agents — and an understanding of the user-facing workflows

these platforms require.

• Strong frontend expertise: React (or Next.js), TypeScript, modern state management, and

component design.

• Solid backend experience: Node.js and / or Python, with REST and / or GraphQL API

design.

• Experience with real-time technologies — WebSockets, SSE, and streaming UIs.

• Strong database skills across SQL and NoSQL (PostgreSQL, MongoDB, Redis, or

similar).

Experience with cloud deployment, CI/CD, containers (Docker), and Git-based workflows.

• Track record building complex, interactive UIs — workflow builders, dashboards, or no-

code / low-code tools.

Nice to Have

• Familiarity with visual workflow / node-based editor libraries (e.g. React Flow).

• Experience integrating LLM APIs and streaming responses into a user interface.

• Exposure to multi-tenant SaaS frontends and design systems

Remote position

Full-stack developer | .NET Core + Angular

Are you...

• Interested in working at a successful, well-funded scale-up where every team member can make a huge contribution?
• Keen to make software that people will use every single day to make their lives easier?
• Excited to work on greenfield projects with responsibility and independence?
• Ready to develop and use your skills across our frontend, backend and mobile offerings?
• Meticulous about quality, and gifted with a strong desire to write beautiful code?

About the company

KeyNest solves the key exchange problem for Airbnb users. Our worldwide network of over 4,000 shops store keys so that Airbnb guests / cleaners / contractors can pick them up whenever is convenient for them. As a global partner of Airbnb we’ve checked-in over 2 million guests.

Why we need you

As the entire Airbnb ecosystem increasingly relies on KeyNest, our customers expect us to integrate additional features without reducing the ease of use that our customers love. This is why we continue to invest in beautiful, intuitive user interfaces that integrate with every tool and are used by our customers, their guests and staff, as well as our own staff.

A product manager, a team lead, two full-stack developers, one mobile developer, and a UX designer make up our product team. Who will serve as your mentor. We are looking for a developer who cares about how their code affects users so that we can work together.

With a genuine passion for high quality work, attention to detail and readiness to own your own projects, you will be looking for a new and exciting challenge which allows you to use your experience to drive change and maintain the high standards of our organisation.

Our Tech Stack

• C# MVC modern tech stack
• .Net Core
• Front end web in TypeScript & Angular
• Test Driven Development (TDD) and follow SOLID design principles.
• EF 6.0
• SQL Server 2017
• Agile experience (Scrum, Kanban)
• TFS
• Cloud hosted in Azure with micro-services architecture

Your qualities

• 5+ years experience in C#
• Experience with .NET core
• Front-end web experience in Angular and CSS
• Track record of building great products
• You’ll love the idea of being a big part of a small team. Current team size is 5.
• Motivation and ambition to succeed in a fast-paced environment
• Not afraid to take on responsibilities

What we offer

• Crucial role in a funded, dynamic & fast-growing scale-up shaking up the sharing economy
• Competitive salary based on relevant experience
• Flexible working for our most committed staff
• Unparalleled opportunities to develop your career as the company develops rapidly

If you want to join the KeyNest team, please get in touch – we look forward to meeting you.

We are an equal opportunity employer and value diversity at our company. We do not discriminate on the basis of race, religion, colour, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.

Job Description:

At Helios Tech Labs we are looking for a Full Stack Developer with <2 - 5 yr Exp> to build and maintain functional websites and applications with highly skilled computer programmer who is comfortable with both front and back end programming.

To be successful in this role, you should have extensive experience building web-apps from scratch and in-depth knowledge of at least one of the following programming languages:

• JavaScript
• Java
• HTML
• CSS
• React
• Angular
• Objective C
• Scala
• Python
• C#
• C++
• PHP
• Perl
• Node JS
• Ruby (RoR)
  
  

Responsibilities:

• Identify user and system requirements for new websites and applications
• Designing user interactions on web pages.
• Developing back-end website applications.
• Creating servers and databases for functionality.
• Ensuring cross-platform optimization for mobile phones.
• Ensuring responsiveness of applications.
• Seeing through a project from conception to finished product.
• Meeting both technical and consumer needs.
• Staying abreast of developments in web applications and programming languages.
• Prioritize software development projects, set timelines, and assign tasks to team members.
• Write or review code for various applications.
• Run functionality testings and debug code.
• Oversee junior web developers and evaluate their performance.
• Liaise with designers to decide on UI/UX elements (like graphics and navigation buttons).

• Build the front-end of applications through appealing visual design
• Good understanding of REACT application, Native Android, System architecture, and workflows
• Experience with function and class components, hooks and material UI, CSS, styled-components preferred
• Understanding of RESTful APIS, HTML/CSS, ES6 (variables and scoping, array methods), GIT, popular frontend development tools, CI/CD tools, DevOps
• Understanding in JavaScript, object model, DOM manipulation and event handlers, DataStructures, Algorithms, JSX
• Must have knowledge in Script frameworks ReactJS, Redux, jQuery and Android Language: Typescript/ JavaScript/ JAVA / XML
• Build reusable code and libraries for future use
• Good problem-solving, Open-minded team player, troubleshooting skills

• 6-13 years’ experience designing for high performing digital products across various domains
• Degree in design-related field or equivalent experience.
• Good understanding of design patterns, industry trends, and great approaches to solve problems
• Expertise in core UX disciplines including information architecture, interaction design, application of design systems, and UI design.
• Creative problem-solver with a strong eye for detail
• Experience and understanding of Responsive Web Design
• Experience with iOS and Android Mobile App Design
• Must have Software Proficiency with Figma, Sketch, Miro
• Proficient in wire-framing and comfortable producing concept sketches and user flows
• A passion for UX and User Research
• A strong portfolio which demonstrates work across a range of clients
• Strong experience of user research and usability testing
• Passionate about Design Thinking.
• Excellent verbal and written communications skills.
• Experience with accessibility, localization, and internationalization.
• Experience working directly with developers to ensure the successful implementation of a design specifications
• Familiarity with content strategy, content management, taxonomy and large scale digital publishing.
• Knowledge of HTML, CSS, and JavaScript.
• Knowledge with QA and testing methods is a plus.
• All candidates will be required to submit a portfolio of work samples and/or links to their work.

• Bachelor’s degree in Computer Science, Software Engineering, or a related discipline
• 4+ years experience working in an IT environment
• 4+ years of Object-oriented design, functional programming
• Node JS API Development (Firebase API development is a plus)
• Angular or VUE or React JS Front end Development (VUE Js Experience is a plus)
• HTML / CSS responsive development
• Experience using any database
• Experience developing in an Agile / SCRUM Environment
• Experience developing mission-critical applications
• Strong business and technical acumen
• Excellent verbal and written communication skills