Senior Engineer (Python / AWS / On-Premise)

Caddie; Toronto; On-site; CAD 100,000 - 180,000; Full time

Job summary

Caddie builds software for analytical testing laboratories and regulated industries. You will own server-side components, from cloud to on‑prem deployments, and ensure accurate data handling from instruments to the lab software.

You will design scalable data processing, work with FastAPI, NumPy, and SQL, and contribute to an architecture that runs in customers' environments with strong data integrity and audit trails.

Qualifications

• Strong Python and SQL skills, with NumPy experience.
• Experience shipping software on customers' servers and in cloud/on-prem environments.
• Ability to design systems with both cloud and local twins and avoid dual codebases.

Responsibilities

• Build end-to-end product features for cloud and on-prem deployments.
• Work on the engine that runs at scale with containerised Python workers.
• Read and write binary instrument files and maintain data integrity.

Skills

Critical thinking

Proactivity

Ownership

Fast and careful work

Adversity handling

Tools

Python

NumPy

SQL

AWS

FastAPI

Terraform

CDK

PostgreSQL

Job description

Caddie Intelligence builds software for analytical testing laboratories and other regulated industries.

WHAT WE'RE BUILDING

Something meaningful, in an industry that quietly touches billions of lives and almost nobody thinks about. The work inside it is slow, manual and consequential and the decisions being made every day deserve to be faster, more consistent, and easier to stand behind.

THE ROLE: YOU WILL BUILD IT END TO END

One product, two homes: our cloud, and inside our customers' own buildings. You own everything that runs on a server, wherever that server is.

• The engine at scale: containerised Python workers (FastAPI, NumPy, SciPy) that make the same decision on every machine, byte for byte
• Instrument files: read the binary files laboratory instruments produce, and write Caddie's decisions back into them so the lab's own software still opens them and does the maths
• New test methods: turn a new laboratory test into a working module with the founders, following our written playbook
• The cloud: S3, SQS, ECS Fargate, KMS
• The on-premise edition: the same engine and the same app running inside a customer's network with no internet. Containers, local Postgres and file storage, signed offline updates, Windows and Linux servers
• The record: immutable storage, hash-chained audit events, ten-year retention, in both homes
• The self-serve layer: schema design, immutable versioning, approval workflows
• The plumbing: Terraform or CDK, CI that blocks regressions, monitoring

WHAT YOU'LL NEED

• Strong Python, including NumPy, and SQL well past CRUD
• You care about exact numbers. You know why the same calculation can give different answers on two machines, and how to stop it
• Comfortable taking apart a binary file format nobody documented
• AWS deep enough to design it, not follow a tutorial
• You have shipped software that runs on someone else's servers, not just your own cloud
• You can design one system with two homes, where every cloud piece has a local twin and nobody maintains two codebases
• Enough front-end ability to ship a screen yourself when it is faster than asking
• You use AI tooling hard, and you are ruthless about reviewing what it writes (Cursor, Claude Code, Codex, etc.)

NICE TO HAVE

• Signal processing, chromatography or other scientific data
• Regulated software: audit trails, data integrity, validated systems
• Docker, air-gapped installs, Windows Server

WHO YOU ARE

• Critical thinker who pushes back
• proactive, nobody is going to hand you a ticket
• wants ownership of the schema, the server and the alarm that wakes you up
• fast without being sloppy
• ability to handle adversity

NOT REQUIRED

• A specific number of years. We care whether you can do the work, not how long you have been doing it
• Any degree or higher education

WORKING HERE

• A direct line to the founders. No waiting a week for a decision
• Fast paced environment, team retreats, ability for your voice and ideas to be heard
• You see the whole company, not a slice of it: commercial, technical and strategic
• Access to the network behind us: investors, operators and advisors who have built and sold companies in this space
• You grow as the company grows, and you will be able to point at the parts that are yours

Caddie is backed by ERA, the New York accelerator.