Cliff Crosland, Developer in San Francisco, CA, United States
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Cliff Crosland

Verified Expert  in Engineering

Software Developer

San Francisco, CA, United States
Toptal Member Since
October 18, 2017

Cliff is a full-stack software engineer who has had the opportunity to work on some remarkable technology, including systems to crawl the web and process hundreds of millions of extracted profiles from web-pages. He's passionate about building elegant APIs and processing systems as well as beautiful front-end web experiences.


ClojureScript, Amazon DynamoDB, PostgreSQL, C++, Ruby on Rails (RoR), Ruby
Seed Equity
Microsoft SQL Server, PostgreSQL, C#, Angular, Node.js
MySQL, Scala, Java




Preferred Environment

Git, Vim Text Editor, Linux, Unix, MacOS

The most amazing...

...thing I've built is an infrastructure to download millions of web pages and extract hundreds of millions of person and company profiles from raw HTML documents.

Work Experience

Software Engineer

2015 - PRESENT
  • Scaled the throughput of the main data ingestion pipeline from a rate of a few hundred thousand profile objects per week to over a hundred million profile objects per week by introducing an internal framework to parallelize tasks running in Ruby on Rails and Resque.
  • Optimized data access patterns at scale, moving data as needed from PostgreSQL to DynamoDB for better write performance.
  • Built a C++ extraction system to analyze raw HTML documents and intelligently extract structured person profiles, using consensus signals from our data to detect high-quality matches.
  • Designed and built a search back-end using Algolia for fuzzy text search and advanced facet search and built web front-end components using Reagent (a ClojureScript React wrapper) to highlight notable search results.
  • Designed and implemented AWS server topology for the data processing pipeline, using AWS components like EC2, RDS, DynamoDB, and ELB and integrated monitoring services like New Relic, Grafana, Pingdom, and PagerDuty.
  • Built an email system for sending personalized news and event notifications to users and integrated analytics systems like Mandrill and Amplitude to optimize open rates.
Technologies: ClojureScript, Amazon DynamoDB, PostgreSQL, C++, Ruby on Rails (RoR), Ruby

CTO | Co-Founder

2013 - 2015
Seed Equity
  • Led the technology team for the seed equity crowd-funding platform, implementing the majority of the functionality, and led a team of two other engineers.
  • Designed and implemented dynamically scaling micro-services written in Node.js and C#.
  • Built the front-end web user-experience using Angular.
  • Designed and implemented our AWS server topology, using EC2, RDS, Elastic Beanstalk, Elasticache, S3, and CloudFront.
  • Built the data layer powering the web experience using PostgreSQL, SQL Server, as well as integration with third-party secure document storage to comply with financial regulations.
Technologies: Microsoft SQL Server, PostgreSQL, C#, Angular, Node.js

Software Engineer

2012 - 2013
  • Built and shipped Addepar's financial platform to beta customers in the venture capital industry.
  • Designed graph-based models and financial algorithms for venture capital financial structures.
  • Created native desktop UI in Java Swing to allow venture capital customers to build interactive reports.
  • Built backend financial data processing engine in Java and Scala to rapidly compute financial ownership positions.
  • Designed efficient data access patterns in MySQL to store financial graph data.
Technologies: MySQL, Scala, Java

Accompany Data Pipeline
Built an infrastructure to download millions of web pages and extract hundreds of millions of person and company profiles from raw HTML documents.

Wrote task processors in Ruby and C++.

Managed hundreds of millions of objects in our storage system—consisting of PostgreSQL, DynamoDB, and S3.

Designed and implemented Accompany's typeahead and advanced facet search system using a hybrid of Algolia and PostgreSQL.

Black-Hole.js | Render Gravitational Lensing in a Browser
A JavaScript library that renders black hole gravitational lensing effects in an image canvas using WebGL, glfx.js, and Numeric.js.

The library uses a numerical ordinary differential equation solver from Numeric.js, and some nice WebGL utilities from glfx.js, to render the gravitational lensing of a black hole.

You can read more about the project and the fun challenges it posed in my write-up here at the link.


JavaScript, Ruby, Python 3, C++, Clojure, Java, Scala, C#


Ruby on Rails (RoR), Pyramid, Django, Angular, ClojureScript


React, Node.js


Vim Text Editor, Git


PostgreSQL, MySQL, Redis, Microsoft SQL Server, Amazon DynamoDB


Software Development


Functional Programming


Linux, MacOS, Unix

2006 - 2012

Bachelor of Science in Computer Science

Stanford University - Palo Alto, CA, USA

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