About Us

Our Mission: Make GTM Simple

Powerful technology is not enough. GTM leaders are promised transformation, then left with disconnected workflows, inconsistent execution and teams that spend more time researching than selling.

OneSales makes the work simpler.

We help you cut through noise and deliver tools that drive real impact on revenue and execution.

Our focus is on adoption that works in the real world, delivering revenue, not generic AI hype.

We turn manual workflows into a consistent, automated revenue engine.

Our approach

25+ Years of GTM Sales Experience

We’re product builders, operators, and founders who know how hard it is to drive real change in GTM.


At OneSales, we turn that experience into solutions that create focus, improve execution, and deliver consistent, measurable results.

2000+ GTM Leaders

We’ve worked with over 2,000 go-to-market leaders, including CROs, RevOps teams and frontline managers across fast-growth and enterprise organisations.

We understand the real state of sales because we’ve lived it, not viewed it from the outside.

Built for Real GTM Teams, Not AI Labs

We understand the pace, pressure, and complexity of sales organisations.


OneSales is built to bring clarity, consistency, and measurable impact to GTM execution, helping teams move faster, make better decisions, and operate at a higher standard.

Our team

We have built companies, led sales teams and shipped software. OneSales comes from problems we have dealt with ourselves.

Seamus Devine

Seamus Devine

Founder & CEO

Seamus is the founder and CEO of OneSales. He has spent more than 20 years in enterprise sales and has helped grow companies including TIBCO, BEA Systems and Software AG. He co-founded ClosePlan, which was acquired by People.ai, and later led several GTM teams there. He also founded FilesConnect and other SaaS businesses. At OneSales, he brings that experience to a problem he knows well: helping sales teams use AI in a practical way.

Seamus is originally from San Francisco and lives in Prague. Outside work, he enjoys travel, running and time with his family.

Seamus Devine

Jiri Zajpt

Founder & CTO

Jiří is the co-founder and CTO of OneSales. He co-founded Blueberry.io and helped grow it from two people to a team of more than 100 before its acquisition in 2019. He later held technical leadership roles at Keyrock and BOOTIQ, working on complex systems and engineering teams.

At OneSales, Jiří leads product architecture and engineering. He lives in Prague and spends time mentoring engineers and working through difficult technical problems.