Founder Profile
Eric Costello
Last reviewed: October 2026 · By Swet Parvadiya
Who is Eric Costello?
Eric Costello is a founder of Slack Technologies, LLC, which was founded in 2009 with Stewart Butterfield, Cal Henderson and Serguei Mourachov.
- Company founded
- Slack Technologies, LLC
- Founded
- 2009
- Co-founders
- Stewart Butterfield, Cal Henderson and Serguei Mourachov
Background
Software engineer and tech entrepreneur.
Founding Story
Eric Costello co-founded Slack in 2009. Having previously worked with Butterfield and Henderson at Flickr, he helped build the absolutely critical early client-side architecture for the failed video game 'Glitch,' which ultimately pivoted into the massively successful Slack desktop application. (Exact birth year remains publicly undisclosed).
Sources
This profile does not yet cite a source specific to Eric Costello. The sources below document the company company rather than the person, so check them against the claims above.
- Slack Announces Strong Fourth Quarter and Fiscal Year 2021 Results (Slack Technologies, LLC)
- Slack Technologies SEC filings (EDGAR) (Slack Technologies, LLC)