Senior Software Developer

Kultakiertue Oy; Helsinki; On-site; EUR 72,000 - 90,000; Full time

Benefits offered by this job

Unlimited AI tokens

Competitive salary

Career growth

Ownership of security

Supportive team

Job summary

Kultakiertue Oy, a Helsinki-based scale-up, seeks a hands-on Senior Developer to join our in-house engineering team. You will build secure, mobile-first web apps using SvelteKit, Node.js, TypeScript and PostgreSQL, shaping architecture and data flows across our platform.

You will own security in day-to-day development, implement access controls, handle personal and financial data safely, and collaborate on compliance reporting as we expand into new markets.

Qualifications

• Proven track record building complex, mobile-first web apps (Svelte/SvelteKit or similar).
• Strong experience in backend and/or frontend development (Node.js, TypeScript, React, Vue or similar).
• Solid database and integration skills (PostgreSQL, REST APIs, row-level security a plus).
• A security-first mindset: you think about authentication, authorization, PII handling and the OWASP Top 10 as part of normal development.

Responsibilities

• Develop new features and integrations across our internal apps (routes, bookings, payments, etc.).
• Help with planning and managing country-specific compliance and reporting requirements.
• Own security in day-to-day development: access control, secure handling of personal and financial data, and safe integration patterns.
• Contribute to secure architecture and technology decisions, including threat modeling, testing, code review, and dependency and secrets hygiene.
• Build and maintain integrations.
• Monitor and optimize workflows, data quality and system reliability.
• Support broader IT and software needs across the company.

Skills

SvelteKit

Node.js

TypeScript

PostgreSQL

REST APIs

Security mindset

Data protection

Startup experience

English fluent

Tools

Vercel

Supabase

Job description

Are you looking for a responsible role in a fast-growing Helsinki-based scale-up with strong multinational business and rocketing growth? Do you have solid experience in software development, and do you take security just as seriously?

How does a key role in a rapidly growing success story sound? At Kultakiertue, we are the market leader and pioneer in the purchasing and evaluation of precious metals. We already operate in the Nordics, Europe and the USA, and we keep expanding into new markets. More than 100 professionals work within our unique service concept, and our growth is only accelerating. Now is the perfect time to join.

We're looking for a hands-on Senior Developers to join in-house engineering team, using modern frameworks and tools like SvelteKit, Vercel, Supabase and PostgreSQL.

Our internal software runs the whole business end to end: routes, bookings, field ops, payments, controlling, compliance and more. Because we handle customer data, banking and regulatory reporting to authorities in multiple countries, security and data protection are not an afterthought for us. They are a core feature of the product, and you'll help keep it that way as we expand into new markets.

Key responsibilities

• Develop new features and integrations across our internal apps
• Help with planning and managing country-specific compliance and reporting requirements
• Own security in day-to-day development: access control, secure handling of personal and financial data, and safe integration patterns
• Contribute to secure architecture and technology decisions, including threat modeling, testing, code review, and dependency and secrets hygiene
• Build and maintain integrations
• Monitor and optimize workflows, data quality and system reliability
• Support broader IT and software needs across the company

What you bring

• Proven track record building complex, mobile-first web apps (Svelte/SvelteKit or similar)
• Strong experience in backend and/or frontend development (Node.js, TypeScript, React, Vue or similar)
• Solid database and integration skills (PostgreSQL, REST APIs, row-level security a plus)
• A security-first mindset: you think about authentication, authorization, PII handling and the OWASP Top 10 as part of normal development, not as a separate phase
• Experience working with sensitive data (personal data, payments, or regulated/compliance-heavy domains) is a strong plus
• Familiarity with GDPR and practical data-protection engineering is appreciated
• Experience in fast-paced startup environments
• Fluent English (Finnish or other Nordic languages are a plus)

What we offer

• A truly agile, tight team environment where your ideas matter
• Responsibility and freedom to influence architecture, technologies, security practices and ways of working
• Unlimited AI tokens and the modern tools and resources you need
• Real ownership of security in a domain where it genuinely matters: precious metals, payments and regulatory reporting
• A supportive, skilled and growing team
• Competitive salary and company bonus scheme
• Career growth opportunities in a rapidly scaling company

More information

The salary for this position ranges from 6000-7500 € per month, depending on the selected candidate’s skills and experience.