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CV

# author: matjam # date: 2026-07-28 # plain text # pdf

Nathan Ollerenshaw

Backend and platform engineer who sets technical direction beyond the teams they lead. Track record of framing opportunities the organization had not yet framed for itself — a product data publishing platform that generated over $1M, an organizational shift in CI and infrastructure strategy, an LLM-assisted rewrite that cut primary read latency by 20–100× — and of building the internal infrastructure other engineers build on top of. Deep background in Go, Python, AWS, distributed systems, and developer tooling.

San Francisco Bay Area | Authorized to work in the US (Green Card holder)

matjam@stupendous.net | linkedin.com/in/nathanollerenshaw | github.com/matjam | stupendous.net

Core Strengths

Technical direction at organizational scope · Influence without authority across teams · Distributed systems architecture · Developer tooling and agent infrastructure · Revenue-aligned technical strategy · Multi-year system modernization · Cloud-native infrastructure (AWS) · Event-driven and microservices design · AI-assisted development at production quality · Engineering standards and mentorship

Current Role

Staff Software Engineer, NerdWallet (September 2018 – present)

Nearly eight years across three phases of increasing scope: modernizing a heterogeneous legacy estate onto Go, leading the Product Platform team and its revenue initiatives, and — alongside that charter — building developer and AI infrastructure used well beyond it.

Engineering Leverage and Core Service Modernization

  • Built an MCP server, beyond the team’s own charter, providing semantic search across NerdWallet’s entire source estate — a single interface for cross-repository code discovery, for engineers and AI tooling alike.
  • Designed and built a custom agent harness that closes the loop between a user reporting a problem and a fix reaching review: it triages each report, assesses whether the issue is in scope to fix, opens a pull request when it is, keeps the reporting user informed throughout, and escalates to a human engineer for review.
  • Led the rewrite of NerdWallet’s primary marketplace service in Go, choosing a differential-backtesting approach that used the legacy implementation as a reference oracle so correctness was verified continuously rather than at cutover. Swapped runtime components incrementally over several months with minimal disruption; cutover delivered a 20–100× latency reduction on primary read APIs.
  • Established the verification standard the migration depended on, deriving test cases from the legacy implementation’s observed behavior and covering previously untested paths — taking the codebase to over 80% coverage, approaching 90%.
  • Changed the delivery economics of user-facing work, cutting the cycle for interface improvements from months to weeks by owning architecture and interface design while directing AI-assisted implementation in Svelte and Tailwind.
  • One of the technical leaders who moved NerdWallet’s engineering organization onto AI-assisted development, establishing the practical patterns for using Cursor and Claude in production work and holding the quality bar as output increased.

Product Platform Leadership

  • Engineering Team Lead for the Product Platform team, owning the product data APIs behind every NerdWallet user experience across Python, Go, and React/Node.js/TypeScript applications.
  • Identified a revenue opportunity in internal stakeholder discussions, aligned the organization behind it, and led design and implementation of an automated product data publishing platform — delivered ahead of holiday code freeze, generating over $1M in initial revenue with recurring income established.
  • Owned capacity planning for NerdWallet’s Superbowl ad campaign. The plan held through the traffic surge with no incidents or performance degradation, and did so while I was on a planned sabbatical.
  • Set technical direction for re-aligning the technology stack to NerdWallet’s adoption of the Single-Threaded Team operating model.
  • Took on the WunderGraph Cosmo and GraphQL platforms after other teams relinquished them, integrated them into support processes, then built a reusable Go subgraph framework designed for adoption beyond the owning team as federation expands.
  • Drove Core Web Vitals performance analysis and shipped fixes across applications as part of a cross-functional team.
  • Sustained high availability across team-owned systems with a focus on maintainability and long-term platform durability.

Platform Modernization and Technical Standards

  • Inherited a heterogeneous estate of Python, JavaScript, and Java applications and drove the migration of most critical infrastructure to Go — a multi-year direction change delivering substantial stability and performance gains.
  • Authored the technical white paper that set organizational direction on GitHub Actions and an AWS account-per-team model, then prototyped the migration path from proprietary deployment tooling to GitHub Actions with Terraform and AWS CDK.
  • Built and maintained the core Go frameworks that integrate Go services into the NerdWallet stack on AWS ECS and Kubernetes, and supported multiple teams with Go performance optimization and fixes to shared packages.
  • Rewrote the Data Ingestion Service from Python to Go, replacing hard-coded rules with a declarative YAML configuration system, cutting debugging complexity and enabling rule iteration without code changes.
  • Raised the standard for Python practice across the organization, adopting uv, ruff, and FastAPI and refactoring legacy applications to reduce complexity and external dependencies — substantially improving build and deploy times.
  • Early adopter of the standardized EKS platform, assisting teams with migrations, shaping Helm configuration, and helping refine an AI-based review agent for Helm changes.

Technical Skills

Programming Languages

  • Go: Using Go since its 1.0 release in 2012. Extensive production experience building microservices integrated with AWS (ECS, EKS, DynamoDB, S3), PostgreSQL, Redis, and OpenSearch.
  • Python: Production experience across web services (Flask, FastAPI), async programming (gevent, asyncio), data layers (SQLAlchemy, Pydantic), and complex data processing.
  • C/C++/Java: Production C systems spanning databases, SOAP/REST APIs, sockets, and threading. Professional C++ and Java experience; follows modern C++ and uses it for personal projects.
  • SQL: Oracle, MySQL and PostgreSQL, with a strong grounding in optimization, indexing, and query planning.
  • Full Stack Web Development: Delivers complex user-facing features end to end, owning the frontend architecture and interface design while directing AI-assisted implementation in JavaScript and TypeScript across React, Svelte, SvelteKit, and Tailwind.
  • Bare metal experience with x86_64, 68k, and 6502 assembly. Some FPGA programming. Interest in Rust.

AI Tooling & Developer Experience

  • Agent Infrastructure: MCP server design and implementation; custom agent harnesses for automated issue triage, fix assessment, and pull request generation with human review gates.
  • AI-Assisted Development: Cursor and Claude in production workflows; LLM-driven code generation validated by differential testing against reference implementations.
  • Developer Experience: Python toolchain modernization (uv, ruff); internal frameworks and shared libraries built for other teams to adopt.

Infrastructure & Cloud

  • AWS: ECS, EKS, DynamoDB, CDK, and core AWS services.
  • CI/CD: GitHub Actions, Buildkite, Jenkins — pipeline design, optimization, and standardization. Infrastructure deployment with Terraform and AWS CDK.
  • Containers & Platforms: Docker, Kubernetes (EKS), Helm; GraphQL federation (WunderGraph Cosmo).
  • Systems & Configuration: Linux (Ubuntu, RHEL/CentOS), FreeBSD, Solaris; Puppet, Ansible; NGINX, Apache, HAProxy.

Data & Networking

  • Data: Oracle, MySQL, PostgreSQL (clustering, optimization, administration); Redis, OpenSearch; RabbitMQ, OpenMQ, ZeroMQ.
  • Networking & Security: Expert-level DNS; IPv6 deployment; routing, switching, and load balancing (Cisco); PCI-DSS 3.0 compliance audit experience.

Earlier Career

Two decades of infrastructure at national and carrier scale, moving from running other people’s systems to designing the ones other people depend on.

Senior Solutions Engineer, Cloudmark / Proofpoint (2015 – 2018) — Deployed the Cloudmark Security Platform at Videotron, Verizon and Sprint, then drove the initial design of SMC 2.0 and led the team’s Go REST API development after moving into Solutions Engineering DevOps.

SVP Engineering, BNC Holdings (2013 – 2014) — Ran engineering for a Japan-based mobile payments startup. Delivered a fully PCI-DSS compliant payments platform and shaped the application architecture for compliance by design.

Senior Technical Specialist, Telstra BigPond (2007 – 2013) — Mail and DNS platforms for Australia’s largest ISP. Core authentication and accounting systems in C/C++, the Nominum DNS platforms, and an early-OpenStack mail archival system.

Systems Engineer, ValueCommerce (2002 – 2005) — Designed and built a shared hosting platform for hundreds of thousands of domains, later sold to C-Side and still in production more than twenty years on.

Systems Specialist, LineOne / Tiscali UK (2000 – 2002) — Ran AAA, mail, storage, web, DNS and databases for a top-5 UK ISP (600,000+ customers) through the Tiscali acquisition and the dot-com crash.

Systems Administrator, Modem Media Poppe Tyson (1997 – 2000) — First serious role in the industry. Owned all IT and hosting for the London office through growth from 40 to over 100 staff.