Upstream

Upstream runs Start at Upstream, a 12-month paid graduate program based at its R&D center in Gerakas, Athens, with separate tracks for full-stack, back-end Java, DevOps, and performance marketing. The program opens with roughly two months of structured technical training before trainees join a team for the remaining ten months, each paired with a mentor for the full year. Upstream runs the program from this single site and expects participants in the office daily, so it fits a candidate already targeting Greece rather than one running a multi-city graduate search in parallel.

Upstream reaches 1.2 billion consumers directly through billing relationships with mobile network operators across more than 40 countries in Latin America, Africa, the Middle East, and Southeast Asia, a scale corroborated independently by former investor Actis. In July 2025, Intersel acquired Upstream from Actis Capital, ending Actis's decade as primary investor and installing Intersel chairman Salim Khoury as Upstream's Executive Chairman. The company was founded in Athens in 2001: a new hire is joining a 24-year-old firm under new ownership, not an early-stage startup, which puts the relevant diligence on the new owner's plans rather than on runway.

Not right now. Upstream has no internship or graduate roles listed today; new postings appear here as the firm opens them.

Applications to Upstream go through the firm's own careers site, one application per posting, each expecting a CV and cover letter written for that role.