Building a novel, groundbreaking visual devops / infrastructure management platform with an amazing team.

Primary open source maintainer (with Daniel Lemire) of simdjson, world’s fastest C++ JSON parser, with real-world usage in fundamental places like node.js and algorithms used in Rust, Java.* Designed and implemented novel “on demand” API, allowing high-performance streaming parsing without sacrificing usability (paper: https://arxiv.org/abs/2312.17149).* Created world’s fastest UTF-8 validation algorithm in SIMD (paper: https://arxiv.org/abs/2010.03090).* Numerous speedups of JSON parsing algorithm, totaling more than 25% speedup of a project that was already 4x faster than any other JSON parser when it started.* Built user-friendly C++ DOM interface, making simdjson accessible to many more people.* Planned and executed release roadmaps for major versions of simdjson, starting with 1.0.

[Lynxtool purchased by Figma in mid 2022.]Responsible for improving company-wide C++ practice and infrastructure, and design and implementation of features focused on making UI design more accessible to developers.* Built interactive preview feature for Figma component updates.* Designed and implemented expressive typescript-like iterator processing for Figma C++ code, improving performance by reducing repeated allocations of large lists and maps, especially in loops. * Significantly increased type safety of Typescript <-> C++ bindings, detecting and preventing a number of bugs.* Updated C++ to c++20, increasing expressiveness and type safety / reliability on the C++ side, detecting and preventing bugs.* Primary mentor on writing and debugging safe, effective C++ code, encompassing a significant portion of Figma’s codebase.* Tracked down and fixed many Figma bugs and performance issues as part of primary on-call role.

Responsible for most aspects of visual programming language, including compiler, graphical language editing, execution and debugging UI/UX, and deployment infrastructure:* Built multiple language features into compiler, improving compiler to support complex flow such as loops.* Built intuitive, debuggable visual loop feature end to end, including compiler, language representation, and visual loop creation and debugging UI. * Designed and built multi-user functionality, including identity verification, project security and user management.* Wrote new typechecking engine designed to allow subtyping and type-flexible operations to be compiled to concrete types.* Built multi-environment deployment infrastructure on AWS and Terraform with separately deployable test and production environments using common deployment templates.* Designed and implemented testing strategy, including unit, component and end to end tests allowing an agile full-environment testing pipeline.* Assisted in UX/UI design of all graphical language components including loops, conditionals, general look and feel.

Responsible for Azure’s global datacenter growth speed and stability of Azure-wide monitoring data collection and alerting, including:* Identified and solved multiple-month delays in datacenter buildout by introducing systemic dependency management and automatic workflow across more than 30 services core to the Azure stack. Savings* Built deployment and orchestration for Azure’s primary internal metrics systems, deploying hundreds of clusters weekly with low risk and high reliability.* Identified and filled gaps in automation with high impact on the toolchain, moving critical buildout steps from human intervention to fast-response automated workflow.* Created visualization tools spanning multiple organizations to give a management- and engineering-level view of the status and problems in the pipeline, allowing low-touch day by day control.* Led 10-person team to identify and correct systemic issues in buildout and deployment times with custom data analysis and problem management tools.* Diagnosed multiple-level root causes of pipeline issues and drove resolution of systemic issues in change management.* Mentored many individual SRE engineers on effective engineering, diagnosis, and data analysis.Spread effective engineering, distributed systems design, and diagnosis practices across multiple SRE teams through organized talks, group facilitation and individual mentoring.

Responsible for creation of multiple revenue-generating products, as well as improvements to the scalability of existing product lines. Managed and optimized shipping pipelines, production systems, and incident response, as well as focusing on the enablement of developers to build and operate code at scale.* Created Chef Provisioning, enabling provisioning parallelism at scale, driving millions of dollars of revenue. Used it to speed and strengthen the deployment, operation and development cycles for Chef's server products.* Created the Chef Zero server, removing major barriers to product entry and taking first-experience time-to-value down from hours to minutes, forming the backbone for the popular Learn Chef tutorials.* Scaled flagship Chef Server capacity by >100x with a full rewrite from Ruby->Erlang and CouchDB->PostgreSQL. Live-migrated Hosted Chef with near zero impact to active customers. Guided Facebook through migration of mega-scaled infrastructure.* Reformed on call response for Hosted Chef, slashing false positive alerts by 90% and adding important diagnostics, decreasing response time.* Created "custom resources" feature, dramatically improving operation's ability to develop reusable components for developers.* Improved automation, testing and dogfooding in shipping pipelines, reducing time-to-ship from 2 weeks to 3 days, and increasing ship frequency from 3-4 months to 1 month, while increasing quality.* Through public and private lectures, community “town halls,” and direct engagement, guided customer operations and development groups to scale the size and speed of their production deployment and ship cycle, while reducing risk.* Instituted alerting and “chatops” interaction on shipping pipelines and spearheaded stability reform, decreasing response time and eliminating 90% of release emergencies.* Led 5 engineers to create Push Jobs, a job system in Erlang and Zeromq that coordinates tens of thousands of parallel jobs.

Member of a team which designed and developed compiler for a new functional language for textual DSLs and data mashup, query, processing and manipulation. Specific contributions:* Led team to develop the SQL schema and expression compiler for the new language.* Created HTML and CSV data extraction and expression query for new language.* Wrote Visual Studio language services including completions, outlining and parameter help.* Contributed key insights to textual DSL parser generator, with patents on key elements of the language.* Designed and developed compiler for a new functional language for textual DSLs and data mashup, query, processing and manipulation.Patents:- parser: http://www.google.com.na/patents/US20100088674- compiler: http://www.google.com.na/patents/US20100088685

Member of a team that developed, tested and ran a large-scale distributed storage and processing service used initially to store and analyze logs for Bing.* Co-wrote widely-distributed white paper on test strategies for large-scale distributed services, used across Microsoft.* Wrote and operated environment dashboard and crash dump categorization for test and production services.* Wrote and operated data integrity monitoring system across thousands of machines.* Created full-system tests run during the acceptance pipeline.* Designed and implemented hybrid model-based test framework applicable to both stress and normal tests.

Key member of team which tested and ran Microsoft's large-scale search service. Designed integration test strategy and C# testing framework, managing multiple people to get the core important tools and infrastructure running.* Wrote earliest integration tests, finding critical cross-component issues early in the development cycle.* Wrote and operated widely-used dashboard used to monitor the product’s many test and preproduction environments.* Wrote and operated service to mine crash dumps on thousands of machines, categorize and display the most frequent stacks, helping developers prioritize work.* Designed and wrote scalable distributed build system for the product with .NET remoting.* Wrote test plans, designed and implemented automated tests for the downloading, parsing and indexing of web pages, conversion, and internationalization.* Wrote widely-used tools to aid the running of the system, running programs in parallel on many machines and performing important administrative tasks.

Key developer (see bug list) and owner of HTML forms on Netscape (Firefox) browser, a massive open source project written in C++. Participated in the W3C XForms Working Group. Streamlined the development and shipping process, including writing automated code review tools and the tinderbox3 CI system.

Lead engineer at a 2-person startup, with full end-to-end responsibility for a ticket sales system and shopping cart in Mason, Perl, and PostgreSQL.

As a consultant, John designed and implemented a variety of database-driven network applications, embedding and mentoring teams to ensure long-term maintainability. Companies such as Swiss Bank, MCI-Worldcom, Lycos, the Chicago Tribune, Land's End, and Follett book publishing used John’s deep expertise in Java, C++, Perl, Oracle and Postgres, among others.

Administered Novell network, SysV Unix Server, Progress database, 70-80 client computers with Win3.1/95. Wrote database programs in MS Access and Progress (Symix) to improve efficiency of company’s advertising mailing systems.

Lead software developer for WWW-based educational quizzing system for NCSU chemistry department using C++, Perl, CGI, Linux web server. Deployed in Chemistry lab in a token ring running Netscape on Windows 3.1.

Graph theory research (including the four-color theorem) using C++, T.A.+tutor for Discrete Mathematics; tutor for C++, Advanced Data Structures courses.