Principal Full Stack Engineer

Sleek; Singapore; Hybrid; SGD 100,000 - 140,000; Full time

Job summary

A growing technology company in Singapore seeks a Principal Full Stack Engineer to drive the development of AI-powered solutions. The ideal candidate will have over 8 years of experience in full stack engineering, strong proficiency in JavaScript and Typescript, and a proven ability to design and scale complex systems. This role involves partnering closely with cross-functional teams to deliver impactful solutions and mentor junior engineers. Join a vibrant startup environment focused on innovation and customer experience.

Benefits

Flexible working hours

Employee share ownership plan

Generous paid time off

Qualifications

• 8+ years of full stack engineering experience.
• Experience designing scalable architectures and services.
• Strong proficiency in modern backend and frontend technologies.

Responsibilities

• Architect, build, and scale AI-powered applications.
• Lead end-to-end design and implementation of major features.
• Mentor mid and senior engineers to enhance team skills.

Skills

Javascript

Typescript

Node.js

React

API design

AI integration

Education

Bachelor's degree in Computer Science or related field

Tools

Postgres

MySQL

MongoDB

CI/CD tools

Job description

Through proprietary software and AI, along with a focus on customer delight, Sleek makes the back‑office easy for micro SMEs. We give Entrepreneurs time back to focus on what they love doing – growing their business and being with customers. With a surging number of Entrepreneurs globally, we are innovating in a highly lucrative space. We operate 3 business segments:

1. Corporate Secretary: Automating the company incorporation, secretarial, filing, Nominee Director, mailroom and immigration processes via custom online robots and SleekSign. We are the market leaders in Singapore with ~5% market share of all new business incorporations
2. Accounting & Bookkeeping: Redefining what it means to do Accounting, Bookkeeping, Tax and Payroll thanks to our proprietary SleekBooks ledger, AI tools and exceptional customer service
3. FinTech payments: Overcoming a key challenge for Entrepreneurs by offering digital banking services to new businesses

Sleek launched in 2017 and now has around 15,000 customers across our offices in Singapore, Hong Kong, Australia and the UK. We have around 500 staff with an intact startup mindset.

We have recently raised Series B financing off the back of >70% compound annual growth in Revenue over the last 5 years. Sleek has been recognised by The Financial Times, The Straits Times, Forbes and LinkedIn as one of the fastest growing companies in Asia.

Backed by world‑class investors, we are on track to be one of the few cash flow positive, tech‑enabled unicorns based out of Singapore.

About the Role

Mission

At Sleek, we are on a mission to streamline operations and elevate customer experience through intelligent automation and modern engineering. We are seeking a Principal Full Stack Engineer who will be a key individual contributor responsible for architecting, building, and scaling Sleek’s next generation of AI‑powered capabilities.

As one of Sleek’s most senior individual contributors, you will partner closely with Product, Design, and Engineering Leads to define technical direction, architect robust AI first solutions, and deliver reliable, maintainable software. You will also help integrate AI thoughtfully and pragmatically into Sleek products and internal processes.

You will ensure

• High‑quality, scalable, secure engineering solutions
• Thoughtful and practical application of AI to automate and improve customer workflows
• High‑quality systems capable of supporting advanced AI workloads at scale
• Strong engineering standards, testing, and maintainability
• Clear communication, alignment, and predictable delivery across teams
• Mentorship and technical leadership to elevate the broader engineering team

Outcomes

Deliver High‑Impact Product and Platform Improvements

• Lead end‑to‑end design and implementation of major product features and platform enhancements.
• Deliver solutions that improve performance, reduce operational issues, and enhance scalability.
• Take ownership of a complex technical domain and become the subject‑matter expert for it

Strengthen Architecture and Technical Foundations

• Assess current architecture and propose a 6–12 month roadmap of improvements (performance, reliability, modularity).
• Introduce or refine engineering patterns and frameworks to speed up development while ensuring stability and quality.
• Drive adoption of best practices in API design, modular architecture, and system observability.

Improve Quality, Standards, and Engineering Best Practices

• Establish or refine engineering standards (testing, linting, CI/CD, error handling, code review quality).
• Champion the use of modern engineering tools, including AI‑assisted development and testing tools, to improve team productivity.
• Ensure strong automated test coverage and modern DevOps practices across services.
• Identify recurring technical debt and support requests, and lead systemic fixes rather than one‑off patches

Advance Performance, Security, and Operational Reliability

• Introduce meaningful monitoring, logging, alerting, and resilience patterns for critical services.
• Detect and fix bottlenecks in API performance, data modeling, database queries, or front‑end rendering.
• Strengthen “secure‑by‑default” coding practices and guide teams on potential risks.

Mentor and Elevate the Engineering Team

• Provide hands‑on coaching to mid and senior engineers; uplift the skillset of the entire engineering org.
• Lead architecture reviews, design discussions, and tech deep dives with clarity and influence.
• Act as a force multiplier through clear documentation, reusable components, patterns, and frameworks.

Strengthen Cross‑Functional Collaboration

• Work closely with PM, QA, and Design to refine requirements and ensure stories meet DOR/DOD.
• Communicate proactively about risks, trade‑offs, estimates, and delivery expectations.
• Serve as a trusted partner to business and product stakeholders for complex or ambiguous technical problems

• 8 plus years of full stack engineering experience
• 8 plus years leading delivery of complex systems
• Experience designing scalable architectures, APIs, and services with strong testing and observability.
• Strong proficiency with Javascript and Typescript.
• Strong proficiency in modern backend technologies (Node.js, bonus to have experience with NestJS) and frontend frameworks (React or Vue).
• Strong proficiency with both relational databases (Postgres or MySQL) and no‑SQL databases (MongoDB), along with ORMs like TypeORM and Mongoose.
• Proven track record delivering production‑grade applications in SaaS, B2B, FinTech, or similar environments.
• Hands‑on experience building and integrating AI‑powered features, such as LLM‑based automation, classification, document processing, or workflow enhancement.
• Familiarity with AI development and evaluation tools (e.g., vector search, embeddings, prompt frameworks, or AI‑assisted development tools).
• Solid understanding of cloud platforms (AWS preferred), CI/CD pipelines, and DevOps practices.
• Excellent communication skills and experience partnering with Product, Design, and QA.
• A history of mentoring engineers and raising engineering quality across teams.
• Nice to have: Experience in Fintech (accounting, bookkeeping, etc)

Behavioural fit is also important at Sleek, and we will be looking for candidates that have a proven track record of embodying the below attributes in their recent roles:

Ownership

This shows reliability and helps build trust within the team. We move fast and need to know that everyone will see things through to completion and proactively help to get things back on track when challenges arise. Accountability is really important to us.

Humility

There is so much we don’t know. Humility allows for open‑mindedness to feedback and a willingness to learn from others. It paves the way for collaboration and creates a positive work environment. It is a key ingredient of self awareness and emotional intelligence.

Structured Thinking

Our business is complex with many layers (many services, many countries, many cultures). Regardless of whether you’re more analytical or creative in nature, being able to show sound judgement is important to us. It ensures solutions are pragmatic and balance the needs of the organisation, team and customers.

Attention to detail

You’ll be managing multiple, complex workstreams from numerous stakeholders. It will be important for you to keep track of everything and notice when information is missing or inconsistent.

Excellent listener and clear communicator

We have a variety of nationalities and for many people, English isn’t their first language. For you to excel, you’ll need to be present in your calls and make sure you properly receive and thoughtfully send messages to others in the business.

Analytical Mindset

You have a keen eye for detail and a methodical approach to dissecting problems. You excel at analysing complex systems and processes to identify weaknesses and inefficiencies, and your ability to evaluate multiple scenarios enables you to devise the best testing strategies. You apply data‑driven decisions to enhance testing coverage and performance metrics, ensuring the highest standards of software quality.

Collaboration‑Driven

You thrive in a cross‑functional team environment, working closely with developers, product managers, and operations teams to ensure alignment on requirements and testing goals. You communicate effectively, advocate for quality throughout the development process, and proactively address potential issues before they arise, fostering a culture of shared responsibility for delivering exceptional software.

Data driven

We are a data rich business with ~15,000 small customers. Each decision we make can impact many more people than we realise - so it’s critical that we use sound data to support our strategies and review the success of our initiatives.

Can have tough conversations in a positive way

It’s not a matter of if, but when difficult interpersonal situations arise. Disagreement, conflict and disappointment are a given in a fast moving business where people care about their work. People that proactively have tough conversations with kindness build empathy, trust and great working relationships.

Interview Process

A successful candidate will participate in the below interview stages.

• A ~30 minute chat with a member of the HR Team
• A 2‑3 hour take‑home assessment that covers both backend and frontend, challenging the candidate’s ability to build projects from scratch and adhere to good coding standards.
• A ~90 minute chat with the Hiring Manager and/or another member of the team to validate the technical aptitude of the candidate.
• A ~30‑45 minute chat with the CTO to validate our desired experience.
• Offer + reference calls

We’ll make a non‑binding offer verbally or over email, followed by a couple of short phone or video calls with references that you provide to us.

Requirement for background screening

• Your education
• Any criminal history
• Any political exposure
• Any bankruptcy or adverse credit history

Please be aware that Sleek is a regulated entity and as such is required to perform different levels of background checks on staff depending on their role. This may include using external vendors to verify the below:

We will ask for your consent before conducting these checks. Depending on your role at Sleek, an adverse result on one of these checks may prohibit you from passing probation.

By submitting a job application, you confirm that you have read and agree to our Data Privacy Statement for Candidates, found at sleek.com.

Humility and kindness

Humility is a core attribute we hire for, which means we have a culture of not taking ourselves too seriously and being able to laugh. Kindness is also incredibly important. We are committed to creating and nurturing a diverse and inclusive environment.

Flexibility

You’ll be able to work from home [2-3] days per week. If you need to start early or start late to cater to your family or other needs, we don’t mind, so long as you get your work done and proactively communicate.

Financial benefits

We pay competitive market salaries and provide staff with generous paid time off and holiday schedules. Additionally, you’ll be able to access our flexi benefits scheme for home office equipment or health and fitness expenditure. Certain staff at Sleek are also eligible for our employee share ownership plan and can share in the upside of our stellar growth trajectory as we work toward listing on a prominent stock exchange in the Asia Pacific region.

Personal growth

You’ll get a lot of responsibility and autonomy at Sleek - we move at a fast pace so you’ll be making decisions, making mistakes and learning. There’s also a range of internal and external facing training programmes we run. We’re also at the forefront of utilising AI in our space and are developing a regional centre of AI excellence. It is our intention that if you leave Sleek, you leave as a more well‑rounded person and professional.

Sleek is also a proudly certified B Corp. Since we started our journey in 2017, we’ve committed to building Sleek as a force for good. In just over 5 years, we’ve joined a community of industry leaders like Patagonia, Ben & Jerry's, and P&G who are building an inclusive, equitable, and a regenerative economy. We have planted over 29,271 trees to reforest our ecosystem and saved 7 tons of paper from landfills by processing over 1.4M pages through SleekSign. We aim to Carbon Neutral by 2030.