James Westover

Senior Python Engineer — FastAPI, Django, Distributed Systems & Platform Engineering

Profile

Senior Python engineer with 12+ years of production Python experience across high-scale distributed systems at Uber, Postmates, and HERE Technologies. Deep expertise in FastAPI, Django, Flask, and Tornado for building production APIs and platform services. Track record of leading large-scale Python migrations (2→3) across hundreds of services, designing data pipelines processing millions of requests per second, and building developer tooling that accelerates engineering velocity. Currently building production FastAPI services with ONNX inference, PostgreSQL, and modern Python practices through a Berlin-based consultancy. Available for remote contract engagements.

Key Qualifications for This Role:

Python Expertise (12+ years): Production Python from 2.4 through 3.13 — FastAPI, Django (multiple versions including 3 coexisting in one monorepo), Flask, Tornado, Celery, SQLAlchemy, Pydantic, AsyncIO
Database & Data: PostgreSQL (including PostGIS, pgpool, PgBouncer), MySQL, Cassandra (multi-region, 2–10M QPS), Redis, Elasticsearch, Kafka, extensive schema design and query optimization
Modern Development Practices: FastAPI + Pydantic v2, async/await patterns, comprehensive testing (pytest), CI/CD (GitHub Actions, GitLab CI), Docker, Kubernetes, infrastructure-as-code (Ansible)
Scale: Code running on 30M+ devices, services at 10,000 nodes per data center, data pipelines at millions of events per second, Python 2→3 migrations spanning 90%+ of production services
Remote-Ready: Berlin-based, operating through German-registered company (Westover Labs UG), experienced in distributed team collaboration across time zones

Selected Experience

Westover Labs / Neher Data Services — Berlin, Germany

Founder (Westover Labs) & CTO (Neher Data Services) · 2024 – Present

Build and ship production FastAPI services with ONNX Runtime inference, Pydantic v2 validation, structured logging, and comprehensive test suites — deployed via Ansible and GitHub Actions.
Architect and maintain PostgreSQL-backed knowledge graph service with pgvector for semantic search, full migration management via Alembic, and REST + MCP API surfaces.
Deliver production iOS applications with React Native, subscription monetization, and privacy-first API design where user data is never persisted.
Pioneer AI-augmented development methodology — orchestrating specialized AI agents to deliver team-level throughput as a solo engineer.
German-registered company operating remotely across EU and international clients.

URBN — Philadelphia, PA (Remote)

Software Engineer · September 2024 – January 2025

Maintained Django application managing URBN's internal product catalog across multiple retail brands.
Improved build systems and developer tooling for enhanced engineering efficiency.
Contributed to task processing systems using Celery and Kafka for asynchronous workflow orchestration.

Uber — San Francisco, CA / Remote

Staff Software Engineer · February 2021 – October 2022

Senior technical contributor on Uber's navigation platform — one of the company's largest distributed systems (~10,000 nodes per data center), serving all routing and mapping globally.
Led Postmates acquisition technology integration: maintained business continuity for legacy systems while designing compliant data deletion strategies across distributed databases.
Led critical incident response for GPS millisecond offset bug affecting data integrity across millions of devices globally — diagnosed root cause, coordinated cross-team remediation.
Drove developer tooling adoption — championed devpod adoption through large-scale simulation testing, improving developer productivity across engineering.
Developed Python-based simulation tools scaling test capacity from 500 to 10,000 trips per run using multiprocessing parallelization.

Senior Software Engineer — Python Platform (Office of CTO) · January 2019 – June 2020

Answered the Office of CTO's call to form a dedicated platform team for Uber's enterprise-wide Python 2→3 migration — spanning hundreds of teams and 90%+ of production services.
Mapped the entire Python dependency structure across Uber's microservice ecosystem, targeting the top 200 repositories and achieving 93% service conversion through purpose-built automation tooling.
Became de facto Python support for Uber's data science organization — maintained notebook infrastructure, supported their distributed query system, debugged their Airflow fork.
Major contributor to tchannel-python — Tornado-based Thrift RPC transport library (Python 2→3 migration of the core transport layer).

Software Engineering Manager — Location Platform · February 2018 – January 2019

Founded and built Uber's Location Platform team from scratch — designed GDPR-compliant location data pipeline for global fleet.
Drove platform reliability from ~80% to 97%+ global data ingestion success, directly supporting Uber's RideCheck safety initiative.
Directed anti-fraud program identifying GPS location spoofing, delivering $30M+ in annual savings.
Owned architecture strategy for globally distributed Cassandra infrastructure at 2–10M QPS — consistency model tuning (QUORUM, LOCAL_QUORUM), capacity planning, multi-region deployment.

Postmates Inc. — San Francisco, CA

Senior Software Engineer 2 — Core Infrastructure · June 2020 – February 2021

Led monorepo-wide Python 2→3 migration across 1M+ lines of code serving 100 engineers — navigating 3 coexisting Django versions, deep bytes-vs-unicode incompatibilities, and performance-critical code paths.
Delivered 4x CI build time improvement by orchestrating distributed test execution across Kubernetes pods — transforming 40–50 minute feedback loops into 10–15 minutes.
Participated in weekly war room calls during peak-traffic scaling incidents — real-time incident response alongside infrastructure leadership.
Partnered with infrastructure team on Envoy service mesh and OpenTelemetry distributed tracing adoption.

HERE Technologies — Berlin, Germany

Software Engineering Manager → Senior Software Architect · April 2015 – February 2018

Built engineering organization delivering 8+ concurrent programs — fleet management platform, real-time data pipeline, ADAS prototyping, route planning systems, and corporate OEM partnerships.
Designed Tornado-based backend APIs and React frontends for fleet management with real-time GPS, IMU, and camera telemetry.
Architected lambda data architecture using Apache Storm, Kafka, Elasticsearch, and PostgreSQL/PostGIS for vehicle fleet ingestion and real-time analytics.
Built "Weatherman" orchestration system for dynamic map reprocessing workflows and quality assurance.
Managed technology partnerships with Intel, Nvidia, Audi, and Mercedes-Benz for sensor-to-cloud autonomous driving infrastructure.

Sonobi — New York, NY

Software Engineer · December 2013 – January 2015

Built RabbitMQ-based distributed job processing system using Python multiprocessing for analytics across 250M+ daily ad impressions.
Developed ETL data warehousing pipeline with S3, Redshift, and Python.
Designed probabilistic overlap estimation using HyperLogLog and MinHash with Redis and NumPy.

Education

MBA, Business Administration — Quantic School of Business and Technology, 2017