Senior Security Engineer in Sydney

Immutable is the world's fastest-growing game platform, built to power the next generation of games. Immutable's full-stack product suite powers every stage of game creation and growth from infrastructure to player engagement. Founded in 2018, we're one of the fastest Australian companies to reach unicorn status, raising more than AUD $400M+ at a valuation of AUD $3.5B. Today more than 700 games build on Immutable, and industry leaders like Ubisoft have chosen us as their partner for the future of gaming. Immutable Audience, our newest product line, is the fastest-growing SaaS in our history. We're growing faster than we ever have, and we're hiring the talent who'll take it further.

Immutable builds products for game studios. One side of the business is a marketing data platform that helps studios find and keep players. The other is blockchain infrastructure, including our own Ethereum layer-2 network and Passport, a wallet players use to hold real digital assets. For a security engineer, this means a wide spread of work across web apps and APIs, AWS and GCP, and smart contracts where a bug has a dollar value attached. You’ll join a security team of five and report to our Head of Security. Most of your time will be spent with the product engineering teams, reviewing new services, building threat models with them and fixing issues in their code. Our target is to fix 80% of vulnerabilities before they reach production, and this role is central to hitting it.

You’ll Be Empowered To:

• Own our vulnerability management program, including the Bugcrowd and Immunefi bug bounties and findings from our scanning tools, with a goal of 90%+ SLA compliance on critical and high issues.
• Own the AI agents that review pull requests for security issues and triage incoming bugs.
• A security context layer (threat models, asset inventory, past findings) that lets those agents triage and propose fixes with less human input.
• Keep our threat models and attack graphs current as the product changes.

We'd Love You To Bring:

• Application security depth. You can find a broken auth flow or an injection bug in code, explain why it happened and fix it properly. You’re also a capable software engineer who ships production code, whether that’s a fix in someone else’s service or a tool you built from scratch.
• You’ve built AI tooling yourself. It might be an agent, an automation or an internal tool, and you can tell us what worked, what didn’t and how you knew.
• Solid AWS security experience will help a lot (IAM, network controls, secrets, misconfigurations). GCP, detection and response experience, and web3 knowledge are all useful, though none are deal-breakers.
• Side projects and open source work tell us a lot, so please include them.
• You’ll enjoy this if you like autonomy, work well beside engineers and are happy to help out in other parts of security when a small team needs it. It’s probably not a fit if you’d rather report findings than fix them.

Bonus Points For:

• Web3 experience, such as wallet, smart contract or dApp security. You can learn it here, but it’ll help from day one.
• Deeper detection and response experience, or a real interest in growing into it.
• Experience running a bug bounty program or findings pipeline end to end.

We are proud of the benefits that we offer for all of our employees globally. Here is a snapshot:

• We commit to paying globally competitive base salaries and contributions to a long-term fund.
• Sharing our products' success through Employee Stock Options (ESOP).
• Our flexible working model blends the best of both worlds: Sydney-based employees enjoy hybrid 3 days a week in our vibrant head office, while remote team members can work from home or utilise access to global office hubs via a WeWork All-Access pass.
• Lunch is ordered fresh every day in our friendly office in Sydney CBD.
• Quarterly End of Cycle Celebration Awards.
• USD $500 WFH allowance to set up your home office.
• USD $600 per annum to put toward your internet and phone usage.
• USD $75 per quarter for remote employees to celebrate with local team members.
• We also support our US Employees with Medical and 401K Insurance.
• Our Australian Employees can access Novated Leasing and save money by paying for their car using pre & post-tax dollars.
• We offer up to USD $1,350 per annum for classes, courses, AI tooling or events to support your growth and development.
• Enjoy access to free online courses via Udemy.
• Enjoy USD $800 per year to put toward your health and wellbeing.
• Get 24/7 access to unlimited counselling for you and your family when you need it through our EAP Service.
• Monthly subsidy and discounted rate with ClassPass, including a 1-year free membership to Breethe.
• Paid parental leave.
• Enjoy 2 additional paid annual leave days at the end of the year.
• Enjoy a paid day off on your birthday.

Immutable is committed to building and fostering an inclusive, diverse workplace. We believe in incorporating everyone's perspectives and experiences as this has been a significant driver of our success so far. We are a 2026 Circle Back Initiative Employer. This means a human reviews every application and we commit to responding to every applicant.