Stanford University

Software Engineer at Snowflake

San Carlos, California, United States

Snowflake

Software Engineer

Joined as co-founder and helped build the company from nothing through several major releases to an award-winning set of high-quality mail clients (MacOS, iOS, Android) and skills (Alexa, Slack) for interacting with major mail services (Gmail, Office365). All Astro clients pulled their data from the AWS-hosted Astro service, which maintained state, handled two-way sync and communication with outside mailboxes, normalized notifications and data, and ran all proprietary value-add logic (e.g. chatbots and AI). The service’s architecture and code was very clean and extensible, it handled pretty much any message you could throw at it, and I’m proud of what we built.

-  Designed the service’s microservice architecture
-  Designed the external-service sync framework and wrote Gmail, Office365, IMAP, and CardDAV synchronizers
-  Implemented the message analysis, threading, and content extraction pipeline
-  Built a dynamic message store and implemented a full suite of standard mail functionality
-  Created the protocol for Astro clients and the change tracking data model and server-to-client notification framework to support it
-  Consistently maintained a large set of unit and integration tests

Served as the main point of contact with Microsoft and Google engineering. Contributed bug reports/fixes to several open-source projects: biweekly [iCal], sardine [WebDAV], and JavaMail [IMAP]. Kept Astro's external sync services independent so that server could switch to being a full-fledged local mail store (which didn’t end up happening, but was a cool pivot opportunity). Had some not-so-terrible ideas for naming the company.

Astro received two rounds of funding, primarily from Redpoint Ventures, and was acquired by Slack in 2018.

Interesting technologies I used included functional Java 8 with extensive use of immutable objects, SQL, Amazon Aurora MySQL, Jdbi, (somewhat) FriendFeed-style DB schema, gRPC/protobuf3 interfaces, Maven, TeamCity, Amazon S3, AWS.

Astro Technology, Inc.

Co-Founder / Principal Engineer

Joined with the spinoff of the Zimbra division from Yahoo!. Continued development through 2 major product releases, including a complete rewrite of the tagging system, expanded search capabilities, cross-server data migration and recovery, greatly expanded unit test code coverage, and marked improvements in code quality and defect rate.

Continued participation in the IETF standards process. Wrote, shepherded, and published RFC 5957, “Display-Based Address Sorting for the IMAP4 SORT Extension”. Not kidding, that was pretty cool.

Transitioned off the Zimbra product, cleanly handing off responsibilities and managing knowledge transfer to the remaining engineering team. Joined the new Horizon Files (a.k.a. “Project Octopus”) project, an on-premises corporate file sharing solution for enterprises wary of having their data escape via Dropbox. Wrote much of the central file store logic, helped integrate with the Mozy synchronization engine, developed a robust HATEOAS REST interface to the product, and produced a full complement of unit and integration tests. Worked with the team through product release and helped resolve urgent customer issues once the software was in the wild.

Tech stacks included Java 7, SQL (MySQL), Jetty, ant, Linux, SOAP, JSON, IMAP, Unicode, REST (including HATEOAS), LDAP.

VMware

Staff Engineer

Joined with the Zimbra acquisition. Continued development of the core ZCS application through 3 on-time major releases, including on-the-fly data migration, a complete rewrite of the core MIME parser, significantly enhanced message threading, per-item annotations, greater stability, and major performance improvements.

Worked closely with the core Yahoo! Mail team to create a proof-of-concept of the Zimbra service running on top of Yahoo! Mail data, including adding an additional database port to SQLite for the Y! Mail team’s experimental “bigbox” metadata store. (This SQLite port was then used in production for the Zimbra Desktop offline client.)

Served as main engineering contact with an external vendor preferred by a high-profile customer. Successfully abstracted and reworked the system’s file store model to support the vendor’s HTTP-based blob storage product.

Actively participated in IMAP standards development. Attended several IETF meetings and helped craft and provide early implementations of several suites of major protocol extensions.

Tech stack included Java 6, SQL (MySQL and SQLite), Jetty, ant, Linux, XML and JSON SOAP variants, IMAP, POP, SMTP, RFC822 (etc.), Unicode, iCal, vCard, Atom/RSS, Sieve, REST, LDAP.

Yahoo

Senior Principal Engineer

Joined as the second engineer before company funding and proceeded to grow Zimbra from nothing through 6 major releases to more than 6 million paid seats plus tens of millions of installed open-source users.

Designed and wrote a significant portion of the core Zimbra Collaboration Server backend service, including the database schema, object model for central messaging concepts, robust sharing model, rationalization of support for both tag and folder organization, server-to-client notification system, inter-server request proxying, quota enforcement, mailbox synchronization logic, end-to-end message analysis pipeline (including parsing, threading, charset handling, text extraction, and snippet generation), full client-server sync protocol, XML and JSON SOAP APIs, and POP and IMAP services.

Created the core of the Zimbra Desktop offline client using a client-server model similar to the one used by Lotus Notes. Extended the server codebase to support offline activity and full delta sync, and added a database abstraction layer to support Apache Derby.

Helped onboard, orient, and mentor new engineers. Constructively reviewed a large fraction of server checkins. Had a bunch of truly terrible ideas for naming the company.

Zimbra provided a dual open-source/commercially-supported collaboration suite – tightly integrated email, calendar, contacts, tasks, files, instant messaging, and wiki – targeted at universities, small businesses, and ISPs. It received three rounds of funding primarily from Redpoint Ventures, Benchmark, and Accel Partners and was acquired by Yahoo! in 2007 for $350M.

Tech stack included Java 6, SQL (MySQL and Derby), Tomcat, ant, Linux, XML and JSON SOAP variants, IMAP, POP, SMTP, RFC822 (etc.), Unicode, iCal, Atom/RSS, REST, LDAP.

Zimbra

Founding Engineer

Joined along with the 70-person Onebox acquisition. Wrote the full-stack implementation of Sprint PCS ShortMail, the threaded SMS substitute provided on all Sprint’s browser-equipped phones. Moved back to the core Onebox product and became the expert on and chief liaison with the Openwave Email Mx email store upon which the Onebox stack was built. Took over as technical lead for the Onebox email service, leading a group of 8 engineers and handling code reviews, employee development, annual reviews, and one team member’s severe health issue. Switched to an advanced products role developing the database layer of an experimental next-generation Openwave Messaging mail store, involving extensive coordination between our team and the core messaging team in Santa Barbara.

Openwave provided both a wide range of software infrastructure to wireless providers as well as a carrier-grade white-label email system.

Tech stack included C, SQL (Oracle DB), PHP.

Openwave Systems

Software Architect

Joined when Onebox was approximately 60 employees. Quickly completed an integration with Oracle Calendar Server, picking up PHP and its C extensions along the way.

Onebox provided a unified messaging (email/voicemail/fax) platform to wireless operators, and also self-hosted the software as a free service for the public. It was acquired by Openwave Systems (then <a href="http://Phone.com">Phone.com</a>) in 2000 for $850M.

Onebox.com

Joined as the second engineer and took responsibility for Leverage for Planning, one of the company’s two major products. Met with customers to determine their product needs while also serving as the lead developer on the product. Led a team of 7, including QA and documentation, and managed multiple product releases and deployments on time with good quality.

Interval Logic produced a planning and scheduling software suite directed at the semiconductor manufacturing industry. It was acquired by PRI Automation in 1997.

Dan Karp