Senior Software Engineer | C#/.NET + React | Sydney CBD | $180K–$200K Package

Big Wave Digital; Sydney; On-site; AUD 180,000 - 200,000; Full time

Job summary

Big Wave Digital in Sydney CBD is seeking a Senior Software Engineer to own full-stack development with C#/.NET on the backend and React/TypeScript on the frontend. You will contribute to architecture, ship customer-facing features end-to-end, and help shape engineering standards for high-performance, reliable digital products.

The role offers a $180K–$200K package, five days onsite in Sydney CBD, and real product ownership in a fast-moving fintech environment.

Qualifications

• Strong commercial C# / .NET backend engineering experience.
• Solid hands-on React.js / TypeScript development capability.
• Experience building and shipping customer-facing digital products.
• Strong API and service development experience.
• Experience with multi-region / multi-lingual products.
• Knowledge of i18n and l10n.
• Strong understanding of technical SEO including crawlability and Core Web Vitals.

Responsibilities

• Build and maintain customer-facing features across the product.
• Develop backend APIs and services using C# / .NET.
• Build modern frontend experiences using React.js and TypeScript.
• Take ownership of features from design through development, release and production support.
• Contribute to architectural decisions and technical direction.
• Write clean, readable, testable and maintainable code.
• Improve frontend performance and accessibility.
• Build and maintain multi-region and multi-language product experiences.
• Collaborate with product, marketing and commercial teams on technology that impacts growth.

Skills

C# / .NET

React.js

TypeScript

APIs & Services

i18n / l10n

Frontend performance

Tools

Headless CMS

SEO tooling

Job description

Senior Software Engineer | C#/.NET + React | Sydney CBD | $180K–$200K Package

This Senior Software Engineer role in Sydney CBD is a full-stack C#/.NET and React opportunity paying a $180K–$200K package. Spring is almost here, so maybe it’s time to warm up your career too.

We’re working with a fast-growing fintech exchange operating across crypto and FX, building high-performance digital products used by customers across multiple markets.

They’re after a Senior Software Engineer who can genuinely work across the stack: strong C#/.NET engineering on the backend, coupled with hands-on React and TypeScript capability on the frontend. This isn’t a backend role where you occasionally tweak a React component. You’ll own customer-facing features end-to-end, contribute to architecture, and help shape the engineering standards behind a platform where speed, reliability, conversion and user experience genuinely matter.

This Senior Software Engineer role in Sydney CBD is a full-stack C#/.NET and React opportunity paying a $180K–$200K package. Spring is almost here, so maybe it’s time to warm up your career too.

We’re working with a fast-growing fintech exchange operating across crypto and FX, building high-performance digital products used by customers across multiple markets.

They’re after a Senior Software Engineer who can genuinely work across the stack: strong C#/.NET engineering on the backend, coupled with hands-on React and TypeScript capability on the frontend. This isn’t a backend role where you occasionally tweak a React component. You’ll own customer-facing features end-to-end, contribute to architecture, and help shape the engineering standards behind a platform where speed, reliability, conversion and user experience genuinely matter.

What you’ll be doing as a Senior Software Engineer

• Build and maintain features across the customer-facing product including the website, onboarding, account creation, promotions and authentication journeys
• Develop backend APIs and services using C# / .NET
• Build modern frontend experiences using React.js and TypeScript
• Take ownership of features from solution design through development, release and production support
• Contribute to architectural decisions and technical direction within the engineering squad
• Write clean, readable, testable and maintainable code
• Set a high standard through thoughtful code reviews and engineering best practice
• Improve frontend performance, accessibility, SEO and overall customer experience
• Build and maintain multi-region and multi-language product experiences
• Work with internationalisation and localisation including i18n, l10n and routing strategies
• Identify and resolve performance, reliability and quality issues before they become problems
• Work closely with product, marketing and commercial teams on technology that directly influences customer acquisition and growth

What we look for in a Senior Software Engineer

You’re likely an experienced Senior Full Stack Engineer who is comfortable taking responsibility rather than waiting for perfectly defined tickets. You’ll bring:

• Strong commercial C# / .NET backend engineering experience
• Solid hands-on React.js / TypeScript development capability
• Experience building and shipping customer-facing digital products
• Strong API and service development experience
• Experience with headless CMS and content-driven architectures
• Understanding of scalable, maintainable frontend architecture
• Experience building multi-region / multi-lingual products
• Knowledge of i18n and l10n
• Strong understanding of technical SEO including crawlability, structured data and Core Web Vitals
• Good engineering instincts around edge cases, failure modes, testing and maintainability
• An eye for frontend quality, usability and conversion, not simply whether something technically works
• A genuine ownership mentality: you care what happens after the code reaches production
• Confidence working in an environment where priorities can move quickly

Nice to have

• Fintech, crypto, FX, trading or exchange experience
• Experience with high-conversion consumer or e-commerce products
• Customer onboarding or identity verification flows, including KYC
• SSO and authentication technologies including OAuth 2.0, OIDC or SAML
• Strong frontend performance knowledge including Lighthouse, accessibility and cross-device optimisation

Why this Senior Software Engineer role

This is a senior engineering role with real product ownership. You’ll be working on technology sitting directly between the business and its customers, rather than disappearing into an internal platform team three layers removed from the product. You’ll have the opportunity to influence architecture, engineering quality and technical direction while remaining hands-on. The business is growing, the product is evolving quickly, and there’s plenty left to build.

The offer

• $180,000 base plus superannuation plus bonus
• Package up to approximately $200,000
• Sydney CBD, five days per week onsite
• Permanent position with real product ownership
• Fast-moving fintech environment

Please note: this position is Sydney-based and requires full Australian working rights. Sponsorship is not available.

If you’re a strong C#/.NET and React engineer who enjoys building products people actually use, this could be a very good way to head into spring.

About this Senior Software Engineer role

Big Wave Digital has placed engineers into product teams across Sydney for well over a decade, so we can tell you what the team is actually like before you interview. If you are weighing up a move, we will be honest about the tech, the people and the trade-offs rather than selling you a job description.

You can also browse our other technology jobs in Sydney, and if you want to sharpen up before interviewing, the official Microsoft .NET documentation is a solid refresher.