Senior Backend Engineer

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Location: Auckland, New Zealand (Hybrid, 3 Days in Office - Britomart/Viaduct Area)

Duration: 6 Month Full-Time Contract (But we are hopeful this will evolve into a permanent position)

About Abby:

Abby's a high-growth B2B SaaS startup literally reimagining the life of accountants all across New Zealand—Australia's next in line (and hundreds of practices are already hyped).

What we do:

We're slashing compliance reporting (the bread and butter for accounting practices globally) from 12 soul-crushing hours to 1 with Automation and AI (in our pipeline), through integration to tools like Xero.

The hundreds of accountants on our waitlist are calling it a game-changer to their work and their life they've waited decades for. Some are even telling us they haven't felt this happy at work in years. That's not an exaggeration Every decision we make is guided by the core principle of making accountants' lives better.

The Role:

As a Senior Backend Engineer at Abby, you'll architect and scale the cloud infrastructure that keeps our platform humming—delivering secure, fast, and reliable systems for accountants across New Zealand, Australia, and beyond. You'll wield AWS like a pro, from Terraform-driven deployments to event-driven workflows, while collaborating with a tight-knit team and tapping into part-time guidance from our Principal Backend Engineer (5 hours/week).

You'll also be heavily involved in transforming accounting logic into the hundreds/thousands of intricate computations behind compliance reports (the year-end lifeline every business gets from their accountant) into clean, blazing-fast, and scalable Python code with the support of an Intermediate Computational Engineer.

If you've got exposure to financial systems, thrive on math-heavy challenges, and obsess over making data scream with speed—especially with async magic—this is your chance to redefine how accountants work, starting in New Zealand, then Australia, and beyond.

Here's what you'll dive into:

1. Writing hundreds—probably thousands—of computations for compliance reports (year-end essentials) and monthly interim reports, weaving market-specific logic (NZ and AUS differ) into intricate, cascading calculations with financial precision.
2. Optimising massive datasets—like workpapers and ledgers with tens of thousands of rows—using Polars and async methods to deliver blazing-fast results for frontend use (and soon, dynamic graphs and charts to support accountants).
3. Pulling data with async speed from APIs (Xero, QuickBooks, and future IRD/ATO integrations), frontend inputs, and user-uploaded files (e.g., CSV, XLSX, PDFs via AWS Textract) to power your computational engine.
4. Crafting unit tests to lock in financial-grade accuracy—because precision is non-negotiable.
5. Architecting bulletproof AWS infrastructure with Terraform, scaling seamlessly from New Zealand to Australia and beyond.
6. Building real-time GraphQL APIs with AWS AppSync, delivering snappy data to power sleek frontend dashboards—and soon, dynamic charts accountants will rave about.
7. Crafting event-driven systems with AWS EventBridge, automating workflows to keep us agile and connected.
8. Managing Amazon RDS (PostgreSQL) and DynamoDB, optimizing databases for speed, scale, and multi-tenant reliability.
9. Deploying multi-region AWS setups, ensuring high availability and low-latency access as we expand globally.
10. Locking down security with Amazon Cognito, delivering robust authentication and authorisation.
11. Automating CI/CD pipelines with GitHub Actions, shipping code fast and flawlessly—no downtime allowed.

Responsibilities

1. Help Build our Computational Engine's Future: scalable, sleek, and primed for a system that'll carry us to Australia and beyond.
2. Ship Phase 2: Launching new features for New Zealand, solidifying NZ, and building out our Australian Product.
3. Expand: Tackle new integrations—QuickBooks & another market is next after this 6-month gig (stick around, we're actually fun)—to make Abby the beating heart of accounting practices.
4. Design and deploy AWS infrastructure for scalability, security, and performance across multiple regions.
5. Develop and optimise GraphQL APIs and event-driven architectures to support real-time operations.
6. Automate testing, builds, and deployments through CI/CD pipelines.
7. Integrate third-party APIs and user-uploaded data into our systems.
8. Collaborate with the team to ensure seamless backend functionality and growth readiness.

Career Growth: We're planning on hiring a lot more to this team over the next few months and years, so there is ample room for career growth.

Our Stack

Infrastructure as Code: Terraform for provisioning and management

Compute: AWS Lambda for serverless scalability

Databases: Amazon RDS (PostgreSQL) for relational data; Amazon DynamoDB for NoSQL performance

APIs: AWS AppSync for real-time GraphQL APIs

Authentication: Amazon Cognito for secure, multi-tenant access

Storage: Amazon S3 for scalable object storage

CI/CD: GitHub Actions for automated pipelines

Testing: LocalStack for local AWS simulation

Languages & Tools:

Python: Core language for backend logic and integrations

Note: We are interested in introducing Go in the near future.

Frontend:

Your computations —feed our frontend via GraphQL APIs. While the UI transitions from Elm to Svelte and TypeScript (handled by others), you'll ensure the data flows fast and clean, powering accountant-friendly displays and, soon, dynamic graphs and charts.

Core Technical Qualifications

Advanced Python & Math Expertise:

Relevant experience crafting high-performance Python applications, with a knack for computational logic and financial-grade precision being preferred.

Proven ability to write modular, maintainable code with Pydantic, solving math-heavy problems—like cascading financial calculations—with elegance and speed.

Experience with asynchronous programming (e.g., asyncio) to handle concurrent data tasks efficiently.

Experience in financial domains (e.g., fintech, accounting, or banking) is a major plus—show us you've tamed numbers that matter.

Data Processing & Storage:

Demonstrated expertise in retrieving and processing large datasets efficiently, with hands-on experience using Polars for high-performance data manipulation.

Ability to work with Amazon S3 for storing and retrieving large JSON files, optimizing data handling for downstream frontend presentation.

Familiarity with querying and managing relational data in databases like PostgreSQL (via Amazon RDS).

AWS Expertise:

Expert Experience with the AWS services mentioned above.

Testing & Quality Assurance:

Strong experience writing and maintaining unit tests in Python using frameworks like Pytest, ensuring computational accuracy and reliability.

Ability to establish high standards for code quality, test coverage, and validation of complex, market-specific calculations —because in finance, close enough isn't enough.

Exposure to AWS Textract or similar OCR tools for extracting data from documents is highly beneficial.

Preferred Technical Competencies

Experience working with the Xero API & Python SDK is a highly desirable skill so that you can hit the ground running from day 1. However, our CTPO and Senior Backend Engineer are experienced with Xero, ready to support you while you get up to speed.

Experience with the Quickbooks API would be the cherry on top to align with where we are heading.

Modular Computational Design:

Background in building modular, reusable Python libraries (e.g., akin to our AccountingMath library), with a focus on clean architecture for computational engines.

Ability to design code that supports a waterfall of interdependent calculations with clarity and scalability.

Experience adapting computational logic to varying requirements across regions (e.g., differing accounting standards between NZ and AUS).

Track record of building reliable, adaptable systems that scale efficiently across multiple markets.

Familiarity with structuring data pipelines for dynamic frontend outputs (e.g., graphs, charts)—a sneak peek at where we're headed next.

Personal Qualities

Problem Solving: Exceptional ability to navigate complex technical challenges with pragmatic, creative solutions and a proactive mindset for continuous improvement.

Great communication skills: Clearly articulate technical concepts and collaborate with cross-functional teams. And also, just be able to get on with the team

Are on the train with us: As our CEO often says, we want people that want to get on the train on this journey.

Take pride in your work: We aren't hiring cubicle-coders, we're hiring people who want to build something rad.

A Lifelong Learner: You are someone who takes a missing skill as a personal challenge to become skilled in that area.

If you don't meet all these qualifications, we still encourage you to apply. We know the best engineers are fast learners. We are most concerned about finding the right person

Culture

We're hiring our first 5 full-time engineers to join this ride. You'll report directly to our Chief Technology & Product Officer (CTPO), giving you the freedom to tackle big and challenging problems and ship work that hits users fast. We're smaller than the giants, sure—but that's why your work will matter more here, and why our culture's built to keep you sane and stoked.

Here's what you're stepping into:

"Bugger Off" Deep Work Policy
Locked into a tricky problem or simply just in the zone? Tell anyone—even the founders—to "bugger off" (with a grin). Slack "focus," pop on headphones, or light up a desk flag; we'll guard your deep work like it's our religion. You're here to do your thing.

WSWM: We Ship Wednesday Mornings (When It's Ready)
No Friday afternoon deploy disasters. We ship Wednesday mornings—fortnightly or whenever the magic's ripe—tested, polished, and proud. Then we celebrate: team lunches at that hole-in-the-wall spot we love, or maybe just cracking a cold one together (non-alcoholic options on deck). It's a win for the code and a win for the crew.

Own Your Hours & Meeting-Free Zones
Remote (Optionally) Tuesdays and Fridays are your canvas—code at 3 a.m., 6 a.m., 10 p.m., or whenever you're unstoppable, as long as your team can Slack you a quick "hey, quick question." No meetings those days—zero. The rest of the week, we keep it light so you're building, not Zooming.

Tools that allow you to GSD.

Learn, Hack, Share – Including Hack Days

Code Review That's Actually Fun

Career That Grows With You

Problems That Matter, Solutions That Stick

Your Birthday Off

Learn more at www.cheersabby.com/careers/why-abby

How to Apply

Apply with the following:

Your CV.

A cover letter that shows who you are and why you are interested in getting involved. Start with your favourite culture item to filter out the other candidates that didn't read this job description ;)

A link to a couple of projects you've been involved with and your involvement (GitHub preferred if possible)

How do your skills match this job?How do your skills match this job?

Your application will include the following questions:

• Which of the following statements best describes your right to work in New Zealand?
• How many years' experience do you have as a Python Engineer?

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