Senior Python Engineer (Hiring Globally)

About the role: We run a distributed, camera-based video monitoring and AI alerting platform. The estate spans an AWS-hosted fleet of services and workers, a GPU-backed computer-vision inference pipeline, a real-time streaming and presence layer, and thousands of on-premise edge "media boxes" that ingest camera feeds, serve video, and stream events back to the cloud. Today the bulk of our backend is ~140 Java 8 services and libraries that have grown over many years. We are building their successor: a clean, modern Python monorepo (trella), and we are migrating capabilities over to it service by service. We are looking for a Senior Python Engineer: a strong programmer first, with real depth in both Python and Java to lead and execute that migration. You will design and build the new Python services, port existing Java functionality across with its behaviour intact, and occasionally maintain and fix the existing Java stack while it remains in production. This is a builder's role at the centre of a major platform modernization. What you'll work on: The new Python platform (primary) A greenfield, strongly-opinionated monorepo built for the long term: • Python 3.14, managed with uv workspaces (libs/, packages/, svcs/, apps/, scripts/), scaffolded from Copier templates. • FastAPI services with Strawberry GraphQL as the primary data API; REST where it's the right fit; Uvicorn ASGI. • psycopg3 straight against PostgreSQL / TimescaleDB using the repository pattern - deliberately no ORM - with yoyo migrations. • Pydantic / pydantic-settings for models, validation, and config; httpx for outbound HTTP; pendulum for datetimes; structlog + OpenTelemetry for observability. • Strict engineering standards, enforced in CI: full type annotations under a strict mypy config, ruff lint + format, and a curated, opinionated set of approved libraries (alternatives are banned at the linter level, on purpose). • A strong testing culture: pytest, TestClient, async tests, real test databases. The legacy Java stack (occasional, ongoing) • ~140 Java 8 services and libraries: REST APIs, SQS/SNS workers, Lambda functions built with Gradle and Bazel, running on Jetty 9.4, deployed to Elastic Beanstalk, ECS, and Lambda. • Domains include alerts, analytics, API, auth, clips, media, presence, notifications, and partner integrations. • You'll read this code to understand behaviour before porting it, keep it healthy with bug fixes and small changes while it's still live, and decommission pieces as their Python replacements land. The platform around it • AWS (us-west-2): EC2/ECS, Lambda, S3, RDS (PostgreSQL/TimescaleDB), ElastiCache (Redis), MSK (Kafka), Kinesis & Kinesis Video Streams, IoT Core, Cognito, SQS/SNS/SES. • A GPU-backed computer-vision inference tier producing the alerts that reach parents' phones. • Edge appliances (Linux + Docker) in the field, reachable over AWS IoT. What you'll do: • Design and build new Python services in the monorepo (schema, data access, business logic, APIs, and tests) to a high, consistent standard. • Migrate functionality from Java to Python: study an existing Java service, capture its real behaviour and edge cases, and re-implement it idiomatically in Python without regressions. • Maintain the Java stack as needed: diagnose and fix production issues, make targeted changes, and keep services healthy until they're retired. • Set and uphold engineering standards in the new codebase: typing, structure, the libs/svcs separation, the repository pattern, testing, and review quality. • Work with data: model schemas in PostgreSQL/TimescaleDB, write correct and efficient SQL, and design migrations. • Own your work end to end: from design through deploy, observability, and on-call follow-through, and drive it to a durable resolution. Responsibilities How we work, and what we expect: • Prefer the right fix to a quick patch. Solve the root cause; don't paper over it. • Follow-through over activity. We measure outcomes, not hours. Work is driven to a correct, durable resolution on a reasonable timeline, not left half-done. • Standards are not optional. The new codebase is opinionated by design; we keep it clean, typed, and tested so it stays fast to work in. • Respect what exists before you replace it. Understand the Java behaviour you're porting; migrate deliberately, with tests, and decommission cleanly. Requirements • Strong software engineer first. Excellent fundamentals: data structures, concurrency, API and data modelling, testing, and writing code others can maintain. • Senior-level Python in production: idiomatic, fully typed, well-tested. Comfort with async, packaging, and a modern toolchain (type checkers, linters, virtual envs). • Solid Java in production: able to confidently read, debug, and modify a large existing Java codebase, and reason about its behaviour well enough to port it. • Strong with relational databases (PostgreSQL preferred) writing SQL directly rather tha...