Senior Full-Stack Engineer - New Product Development

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.

Requirements

Mission:

The Senior Full-Stack Engineer is responsible for owning the architecture, development, and scaling of Sleek’s next-generation digital products.

This role’s mission is to combine backend engineering, API integration, and frontend development to deliver secure, performant, and user-centric web applications that integrate seamlessly with Sleek’s CRM and analytics systems.

You’ll work closely with product, design, and growth teams to take products from prototype → launch → global scale, ensuring:

• High engineering quality
• Full security and compliance
• Strong data integrity
• Smooth user experience

Outcomes:

Build and Launch the MTD Product Backend

• Develop the core backend system for the Making Tax Digital (MTD) product — including sandbox and live HMRC integrations.
• Ensure the product meets production-grade reliability, security, and compliance standards.
• Deliver clear API documentation and support multi-environment deployments (sandbox → live).

Integrate Sleek’s CRM and Analytics Systems

• Connect the product’s backend with Sleek’s CRM for customer and transaction data flow.
• Implement event tracking and analytics integrations (e.g. Mixpanel, GA4, PostHog) for real-time product insights.
• Define and deploy conversion and engagement metrics pipelines to enable data-driven growth.

Deploy to Scalable Production Infrastructure

• Lead the end-to-end deployment of the full-stack system using AWS, Railway, or Vercel.
• Set up CI/CD pipelines and monitoring for uptime, error tracking, and security compliance.
• Achieve production reliability and cost-optimized serverless scaling

Deliver a Secure, Compliant Platform

• Implement GDPR-compliant data handling and secure OAuth 2.0 flows for authentication and integrations.
• Establish and document best practices for encryption, API security, and access control.

Enable Long-Term Maintainability

• Produce clean, testable, and documented codebases using FastAPI / Node.js / React / Next.js.
• Set up unit/integration testing frameworks (Pytest, Jest, Postman suite).
• Ensure future engineers can easily extend and scale the system.

Must Have requirements

• 6 - 8 years of experience as a Full Stack Engineer
• 4 - 5 years of experience as a Back End Engineer
• 3 - 4 years of experience as a Front End Engineer
• 2 plus years of experience in building production B2B SaaS or FinTech products
• 6 plus years of experience in Backend: Node.js / Nest.js
• 6 plus years of experience in Frontend: React / Next.js
• APIs: REST, OAuth 2.0, JSON schemas, Postman
• DevOps: AWS, Docker, CI/CD pipelines
• Security: GDPR
• Database: PostgreSQL
• Proven record of delivering live, production-grade systems independently or as lead developer.
• Experience taking prototypes to production (Replit to AWS/Vercel).
• Experience in working in a fast paced environment of a startup
• Strong grasp of scalable architecture and complex API integrations.
• Confident in making technical decisions in fast-paced environments.
• Bonus: experience with accounting, tax, or FinTech APIs

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.

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.

Interview Process:

The successful candidate will participate in the below interview stages.

A ~15 minute chat with a member of the HR Team

Take Home Assessment:

A take-home assessment to demonstrate your knowledge and skills in both frontend and backend development.

Estimated time: 2 hours.

Note: Assessment is unrelated to Sleek's business, and will not be used or distributed beyond the interview process.

Case study interview

A ~90 minute chat with the member of the team to validate the technical aptitude of the candidate.

Career Deep Dive/Behavioral fit interview

A ~30 minute chat with the senior management to assess behavioural and culture fit

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

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:

Your education

Any criminal history

Any political exposure

Any bankruptcy or adverse credit history

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.

Benefits

Some other great things about working at Sleek…

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. 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. You can also work fully remote from anywhere in the world for 1 month each year

Financial benefits: We pay competitive market salaries and provide staff with generous paid time off and holiday schedules.

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 been 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 be Carbon Neutral by 2030.