Peter Goldstein, Developer in Raleigh, NC, United States
Peter is available for hire
Hire Peter

Peter Goldstein

Verified Expert  in Engineering

Open Source Developer

Raleigh, NC, United States
Toptal Member Since
March 11, 2022

Peter is a hands-on developer, architect, CTO, and technical founder passionate about using best practices to quickly build high-quality products. He has over 20 years of experience building full-stack applications. Peter specializes in Ruby on Rails and Go but is a software generalist who is comfortable working in many languages. He is a committed open-source enthusiast who leverages open source to reduce both the cost and time needed to build the products and features he creates.


Open Source
Ruby, JavaScript, Python, Java, Open Source...
Ruby on Rails (RoR), Go, Python, PostgreSQL, Terraform, Ansible, JavaScript...
Email, Mobile, Open Source, DNS




Preferred Environment

Ruby on Rails (RoR), Go, Amazon Web Services (AWS)

The most amazing...

...thing I've built is a system for automating email authentication for companies that became the foundational technology for Valimail, a company I co-founded.

Work Experience

Maintainer and Contributor

2002 - PRESENT
Open Source
  • Contributed to a wide variety of open-source projects over the course of 20+ years, including projects written in Ruby, Java, Go, and JavaScript and used by millions of developers worldwide.
  • Served as the sole maintainer of Dalli, the preeminent Memcached client library used in the Ruby community, with over 60 million downloads. Rewrote the code to meet modern coding standards and needs. Managed community contributions and questions.
  • Created and published open-source libraries in areas of personal expertise, including email authentication (SPF) and DNS.
Technologies: Ruby, JavaScript, Python, Java, Open Source, Generative Pre-trained Transformers (GPT), Artificial Intelligence (AI)

Co-founder and Chief Technology Officer

2014 - 2021
  • Designed and wrote the first version of Valimail's web application and worker processes (Ruby and JavaScript), proprietary DNS server (Go), and deployment system (Ansible and AWS).
  • Set technical standards for a growing engineering team, including system architecture design, continuous integration at a high level of code coverage, SOLID principles, and component deployment and monitoring standards.
  • Served as the primary database expert on the team, managing database maintenance and evolving the Postgres setup to use logical replication and table partitioning.
  • Continued to develop, extend, and maintain features, including SAML authentication, resource authorization, and support for new email standards to be included in the core web application.
  • Wrote a custom DNS infrastructure in Go to serve DNS requests to support DMARC, SPF, DKIM, and other DNS-based protocols. Individual servers scaled to one million requests per second.
  • Built a DNS scanner to analyze the DMARC, SPF, MX, and related records of tens of thousands of domains on a daily basis.
  • Implemented multiple data processing pipelines in Go that used a combination of Postgres, Kafka, and map-reduce structure to support highly scalable data processing with complex requirements.
  • Rewrote and simplified a React and Ruby on Rails-based reporting system by defining architectural standards, eliminating unneeded layers, and simplifying and unifying components.
  • Developed multiple patented technologies that transformed email authentication and drove the wider industry.
  • Served as a core member of the executive and management teams. Analyzed the market, developed GTM strategy, hired teams, and defined and honed messaging.
Technologies: Ruby on Rails (RoR), Go, Python, PostgreSQL, Terraform, Ansible, JavaScript, Architecture, Open Source, DMARC, SPF, DomainKeys Identified Mail (DKIM), DNS, DevOps, Apache Kafka, Email Authentication, Authorization, Authentication, SAML, React, CircleCI, Agile Software Development, Functional Programming, Devise, HTML, CSS, Bootstrap, REST APIs, APIs, API Integration, AWS Lambda, Back-end, Amazon Web Services (AWS), Full-stack Development, Databases, Documentation, SaaS, SQL, RSpec, Artificial Intelligence (AI)

Technical Committee Co-chair

2016 - 2020
  • Co-chaired the technical working group, helping to educate the messaging, email, and ISP community on security and abuse issues.
  • Presented on several topics of interest to the group, both individually and as part of panels with other industry leaders.
  • Solicited proposals for technical presentations from group members, filtered and edited proposals, and worked with presenters to prepare for conferences.
  • Collaborated with industry experts to propose new internet email and security standards and changes to existing standards.
Technologies: Email, Mobile, Open Source, DNS


2009 - 2015
Goldstein Tech Partners
  • Worked with multiple clients in a "CTO for hire" role, hired by the CEO, and focused on product engineering issues, including system architecture, design and development practices, and team management and composition.
  • Assumed responsibility for site operations and development for a large (10+ million registered users) but recently neglected Facebook game implemented in Rails. Repaired various issues, addressed user and moderator concerns, and updated the app.
  • Reinvigorated a struggling project to build an eCommerce platform for a luxury consignment company. Addressed major project management and technical issues, allowing the team to deliver a functional application in a few months.
  • Served as the sole developer for a behind-the-scenes video startup. Integrated with service providers to support video delivery across platforms. Managed all site operations functions and implemented a wide range of features in Ruby on Rails.
  • Worked with a large (around $100 million) webchat company to improve several aspects of their operations, including video encoding, video delivery, systems monitoring, systems resilience, reporting, and advertising.
Technologies: Ruby on Rails (RoR), Spree Commerce, JavaScript, Apache Solr, MySQL, PostgreSQL, Redis, Memcached, Networking, Agile Software Development, Jenkins, Facebook SDK, Functional Programming, eCommerce, APIs, API Integration, Back-end, Amazon Web Services (AWS), Full-stack Development, Databases, Documentation, SQL, RSpec

Chief Technology Officer

2013 - 2014
  • Took over the development of an existing web application, fixing around 50 outstanding serious bugs and adding continuous integration.
  • Improved XML pipeline processing dramatically, achieving a throughput increase of over 100x by system architecture and code changes and enabling near-real-time updates to inventory.
  • Enhanced web user experience with features like faceted search and filtering (using Elasticsearch), photo carousels (JavaScript and jQuery), and favorite lists.
Technologies: Ruby on Rails (RoR), XML, JavaScript, jQuery, Devise, Agile Software Development, Elasticsearch, Back-end, Full-stack Development, Databases, Documentation, SQL, RSpec

Chief Technology Officer

2012 - 2013
  • Rewrote the company’s initial prototype API in less than one month for vastly improved functionality, robustness, latency, and scalability.
  • Collaborated with the VP of product, external contractors, and a small internal team to define and deliver the company’s v2 mobile products based on the API.
  • Contributed to defining and executing a data ingestion strategy that collected and processed information on 10,000+ sports teams and venues and 1,000,000+ games and results worldwide.
Technologies: Ruby on Rails (RoR), JavaScript, Heroku, HTML, CSS, jQuery, APIs, API Integration, Elasticsearch, Back-end, Full-stack Development, Databases, SQL, RSpec

VP of Engineering

2011 - 2012
  • Provided architect-level guidance to the team, with special emphasis on video processing and delivery, performance tuning, and systems. Designed and built the video transcoding and delivery pipeline.
  • Grew the engineering organization by a factor of four in a challenging recruiting environment with limited resources.
  • Managed feature delivery across a number of different platforms like web and iPhone, using the Agile process in tight partnership with product management.
  • Authored code for several platform components, including the Ruby on Rails web application and Android and iPhone apps. Served as the company‘s technical expert in a number of areas, including OAuth 2.0 and Facebook timeline integration.
  • Promoted internationalization (i18n) strongly and pushed the process to localize all parts of the application in a variety of European and Asian languages, enabling the company to pursue and sign deals with international companies.
Technologies: Ruby, Ruby on Rails (RoR), JavaScript, Heroku, MongoDB, Redis, Video.js, Video Streaming, Facebook SDK, Architecture, Android, Mobile, iPhone, Authentication, OAuth 2, Back-end, Amazon Web Services (AWS), Full-stack Development, Databases, SQL

VP of Engineering

2006 - 2009
Meta Interfaces
  • Served as an integral member of the executive team for a profitable company with revenues in the tens of millions during a period of rapid growth. Had an active voice in defining strategy, setting policy, and responding to high-level challenges.
  • Managed the technical infrastructure required to support the operations of a high volume, 3+ million page views per day video website serving up multiple Gbps of video 24/7, at an average per-user rate of more than 3Mbps.
  • Grew the department from two people to around 15 engineers by recruiting a talented team of software developers, system administrators, and UI specialists.
  • Owned various budgets, including the budget for hardware and software supporting system operations, the personnel budget for the department, and the collocation and ISP budgets.
  • Managed a number of software development and system enhancement projects to add features to the system, address scalability concerns, and improve the overall user experience.
Technologies: Java, JavaScript, jQuery, Video Streaming, Architecture, MySQL, Apache Struts 2, Back-end, Full-stack Development, SQL, Artificial Intelligence (AI)

System Implementing Patented Approach to Automated Email Authentication
Developed a system that implements a novel and eventually patented approach to automating email authentication; the definition of DMARC, SPF, and DKIM records makes it easy to identify and configure all email-sending services for authentication and systems in use by a company or nonprofit, blocking all other systems. It allows organizations to ensure that only those services and systems they explicitly allow can deliver email from their domain to recipients' inboxes. This improves both security and deliverability.

To implement this idea, I built a DNS system consisting of a set of highly scalable DNS servers written in Go and a Ruby on Rails web application that handled configuration and reporting. The whole system was deployed in AWS. I wrote the entirety of the first version myself.

This first version of the system was used by a large number of multi-billion dollar companies, securing an enormous number of emails per day. It became the basis for the Valimail business, which went on to raise tens of millions of dollars in VC funding and remains a going concern today.

Dalli is the preeminent Memcached client in the Ruby ecosystem. It has been downloaded 60+ million times and is used by hundreds of thousands of applications worldwide.

I took over as a maintainer of Dalli from the original developer over six years ago. During that time, I managed contributions from the community, triaged support issues, and answered questions directly and via documentation.

About three months ago, I completed a rewrite of the core Dalli functionality to bring it up to modern Ruby standards and address open issues and new Memcached capabilities. Most notably, I added support for using Memcached's new meta protocol with the gem.

I also significantly revised the gem's documentation, rewriting it for clarity and leveraging GitHub's built-in wiki for better organization.

eCommerce Application for a Luxury Consignment Company

A Ruby on Rails / Spree eCommerce application to support a luxury consignment company and replace their current externally hosted application solution.

I came in as a 'CTO for Hire' and took over the project, which had been in process for one year and a half. I addressed major technical and project management issues, designing technical solutions and refocusing the team on necessary steps to meet the business's requirements. I also worked with a DevOps contractor to ensure the application's production environment would scale.

In addition to these architectural and management responsibilities, I did a lot of "hands-on" coding - implementing a number of key features personally and ensuring they worked as expected. This included the product's continuous integration pipeline (using Jenkins), JSON APIs for intercomponent communication, social login using the Facebook SDK, and implementing text-based search using Lucene / Solr.

The application was delivered to production in four months, and the business was able to successfully transition to the new application, growing on that platform for the next several years.
1995 - 1999

Master's Degree in Computer Science

Stanford University - Palo Alto, CA

1992 - 1995

Bachelor's Degree in Physics

Massachusetts Institute of Technology - Cambridge, MA


REST APIs, Devise, jQuery, Facebook SDK, React, Apache Lucene


RSpec, Terraform, Ansible, GitHub, CircleCI, Apache Solr, Jenkins


Ruby on Rails (RoR), SPF, OAuth 2, Bootstrap, Video.js, Apache Struts 2


Go, Ruby, HTML, SQL, JavaScript, XML, SAML, Python, Java, CSS


Agile Software Development, Functional Programming, Continuous Integration (CI), DevOps


Amazon Web Services (AWS), Mobile, Heroku, Apache Kafka, Android, AWS Lambda


PostgreSQL, Memcached, Databases, Redis, MySQL, MongoDB, Elasticsearch


Open Source, Architecture, Email, DNS, DMARC, DomainKeys Identified Mail (DKIM), Authentication, Email Authentication, Authorization, APIs, API Integration, Back-end, Full-stack Development, Documentation, SaaS, Spree Commerce, eCommerce, Video Streaming, Generative Pre-trained Transformers (GPT), Artificial Intelligence (AI), Networking, iPhone

Collaboration That Works

How to Work with Toptal

Toptal matches you directly with global industry experts from our network in hours—not weeks or months.


Share your needs

Discuss your requirements and refine your scope in a call with a Toptal domain expert.

Choose your talent

Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.

Start your risk-free talent trial

Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.

Top talent is in high demand.

Start hiring