Principal Full Stack Engineer (AI Systems)

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:

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 Asia Pacific.

Mission:

At Sleek, we are building the AI-first operating system for SMEs.

Our mission is to eliminate manual work across accounting, compliance, and financial operations by embedding intelligence directly into the systems that power our platform. We believe the next generation of SaaS will be AI-native, where software orchestrates intelligent workflows rather than simply recording transactions.

We are seeking a Principal Full Stack Engineer who will play a pivotal role in architecting and building Sleek’s AI-powered platform and automation capabilities.

As one of Sleek’s most senior individual contributors, you will design and deliver AI-native systems that combine traditional software architecture with modern AI capabilities such as LLMs, embeddings, intelligent automation, and agent-driven workflows.

You will also act as a force multiplier for the engineering organization, championing AI-assisted development practices and helping the entire team build faster and smarter.

This role is ideal for an engineer who enjoys:

• Designing systems, not just features
• Building AI-powered workflows that eliminate operational work
• Using AI to accelerate engineering productivity
• Creating platform capabilities that unlock product velocity

You will partner closely with Product, Design, and Engineering leaders to ensure Sleek’s platform evolves toward an AI-first architecture.

Outcomes:
Build AI-Native Product Capabilities

• Design and implement AI-powered workflows that significantly reduce manual effort in customer and internal operations.
• Build systems that combine LLMs, automation pipelines, and structured software services to solve complex operational problems.
• Deliver production-ready AI capabilities such as:
• document understanding
• intelligent classification
• workflow automation
• AI-assisted decision support
• Identify high-impact opportunities where AI can create step-function improvements in efficiency and customer experience.
  

Architect the Foundation for AI-Driven Systems

• Design scalable services and platform capabilities that support AI-powered features and intelligent automation.
• Introduce patterns for building reliable AI-enabled systems, including:
• evaluation frameworks
• guardrails and fallback strategies
• observability for model behavior
• Establish architectures that support AI orchestration, retrieval systems, and structured automation workflows.
  

Multiply Engineering Velocity with AI

• Champion the use of AI-assisted development tools such as Cursor to accelerate engineering productivity.
• Introduce workflows where AI assists with:
• feature development
• test generation
• refactoring
• documentation
• debugging
• Develop patterns and tooling that allow engineers to ship faster without sacrificing quality or reliability.
  

Improve Platform Reliability and Performance

• Strengthen observability across services, including monitoring of AI-powered workflows and automation pipelines.
• Identify and eliminate bottlenecks in APIs, data pipelines, and backend services.
• Ensure systems are secure, resilient, and scalable as AI capabilities expand.

Elevate the Engineering Organization

• Mentor engineers on system design, architecture, and AI-enabled product development.
• Lead architecture discussions, design reviews, and technical deep dives.
• Create reusable frameworks, components, and patterns that enable the entire engineering team to move faster.

• 8+ years of full stack engineering experience delivering complex software systems.
• Experience building production-grade SaaS platforms in B2B, fintech, or similar environments.
• Proven experience building AI-powered product capabilities, such as:
• LLM-powered workflows
• document processing systems
• classification or extraction pipelines
• intelligent automation systems
• Strong familiarity with modern AI development techniques, including:
• prompt engineering
• embeddings and vector search
• retrieval-augmented generation (RAG)
• evaluation and monitoring of AI systems
• Advanced proficiency with AI-assisted development tools such as Cursor, including:
• codebase-aware development workflows
• AI-assisted debugging and refactoring
• AI-generated testing and documentation
• designing prompt workflows that accelerate engineering productivity
• Strong proficiency with JavaScript and TypeScript.
• Strong backend experience with Node.js (NestJS a plus).
• Strong frontend experience with React or Vue.
• Experience designing scalable APIs and distributed services.
• Strong experience with relational databases (Postgres/MySQL) and NoSQL systems (MongoDB).
• Experience with cloud infrastructure and DevOps practices (AWS preferred).
• Strong communication skills and experience collaborating with product and design teams.
• A track record of mentoring engineers and improving engineering standards across teams.

• Experience designing AI-first product architectures.
• Experience building internal AI tooling for engineering teams.
• Experience with agentic workflows or automation platforms.
• Experience building data pipelines that support AI systems.
• Experience in fintech, accounting, or financial operations platforms.
  

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:

Interview Process:

The successful candidate will participate in the below interview stages.
Screening Interview:

A ~30 minute chat with a member of the HR Team.

Take Home Assessment:

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.

Case Study Interview:

A ~90 minute chat with the Hiring Manager and/or another member of the team to validate the technical aptitude of the candidate.

Soft Skills / Behavioral fit interview:

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

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.

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 will be required to work from the office at least 2–3 days per week if you are based in Singapore or Australia. For all other hiring locations, the role will be fully remote, with work from home five days a 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 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.