Backend Engineer

Outpost is building the AI global trade engine. The accumulated knowledge of every rule you'd need to sell internationally, turned into infrastructure. Tell us what you're selling. We'll tell you how to sell it everywhere.

We operate as Merchant of Record or Tax of Record across 58+ tax jurisdictions. Full liability transfer, or just the tax layer. We do the analysis, we handle the setup, we absorb the liability.

Sell anything, anywhere. Without compromise.

The Role

This is a Backend Engineer role for someone who wants to build complex financial infrastructure from scratch.

You'll work directly with our engineering leadership to implement payment flows, build tax calculation engines, and create the systems that power international commerce. You'll contribute to product and technical discussions, challenge assumptions, and help guide our technical direction.

We're building the infrastructure that lets businesses sell globally without the usual pain. That means payment processing, multi-currency ledgers, real-time tax calculations, merchant onboarding, and AI-powered compliance tools. Hard problems with real scale.

What You'll Get

Yes, the work is intense. But in return, you'll build critical financial infrastructure that handles hundreds of millions in volume.

You'll have significant input into technical direction, work with a small team of experienced engineers, and shape how Outpost scales. If you want to go deep on payments, tax, and fintech infrastructure, this is the role.

What You'll Build

• Payment processing infrastructure handling hundreds of millions in volume
• Robust ledger and reconciliation systems
• Tax calculation engines for multiple jurisdictions
• Real-time transaction monitoring and risk systems
• Merchant onboarding and integration frameworks
• Platform connections with major e-commerce systems
• AI/LLM powered taxation tools
• AI/LLM powered fraud and risk tools

What You'll Do

Technical Development

• Write high-quality, maintainable code
• Implement core payment and financial systems
• Build secure, scalable backend services
• Contribute to system architecture discussions
• Help establish engineering best practices

System Design & Implementation

• Design and build robust payment processing flows
• Implement internal ledger and reconciliation systems
• Create merchant integration frameworks
• Develop automated monitoring and alerting
• Handle secure financial data processing

Cross-functional Collaboration

• Work with product team to refine technical requirements
• Contribute to API design and implementation
• Collaborate with risk and compliance on system requirements

Example Projects

• Implement a multi-currency ledger that handles real-time reconciliation
• Create the tax calculation engine for a new jurisdiction
• Design the merchant onboarding flow and integration framework
• Build AI-powered tools for automated tax classification
• Implement real-time fraud detection and risk scoring
• Create automated reconciliation systems that catch discrepancies before they become problems, * Not maintaining existing systems. You'll build from scratch
• Not a role where you wait to be told what to do
• Not someone who needs heavy process or detailed specs to be effective
• Not pure execution without input into technical direction

Why This Role Is Different

Most backend roles are about maintaining or extending existing systems. This role is about building complex financial infrastructure from the ground up.

You'll tackle challenges like managing multiple currency ledgers, handling card payment flows, building automated reconciliation systems, and creating AI-powered tax tools. You'll have significant input into our technical direction.

If you're excited about building complex payment systems and want to shape the future of international commerce, this is the role.

Outpost Team

Our team were leaders at Revolut, Airwallex, Adyen and Wayflyer, and we're backed by top-tier investors who have built or backed some of the world's leading fintechs.

What We Offer

• Equity and salary in a well-funded startup
• Ability to own your work and move fast
• Direct access to the founding team
• A global mission with real impact
• Low politics, high output
• A culture of builders, not talkers

Working Style

We work together in person in London. We believe the hardest problems are solved in the room.

Do you have experience in Tax experience?, Do you have a Master's degree?, Ideal background:

• Fluency in a JVM-based language, preferably Kotlin
• Track record of implementing complex backend systems
• Strong engineering fundamentals and coding practices
• Bonus: experience building financial, payments, tax, or compliance systems
• Bonus: familiarity with e-commerce platforms

Signals we care about:

• You write high-quality code and care about maintainability
• You can design systems, not just implement them
• You're comfortable with ambiguity and figuring things out
• You contribute to technical discussions and challenge assumptions
• You want to build from scratch, not maintain existing systems
• Bias for action. You ship, you learn, you iterate