Dmytro Soboliev

Dmytro Soboliev (also spelled Dmytro Sobolyev; handle 'sdya') is a Ukrainian software engineer and co-founder of River AI. As a student in Kharkiv he won a silver medal for Ukraine at the International Mathematical Olympiad 2008 and built a top-tier competitive-programming record (Codeforces international grandmaster; TopCoder and Google Code Jam finalist). He studied Applied Mathematics at V. N. Karazin Kharkiv National University, then worked as a software engineer at Joom, Jump Trading Group in London (2016-2017), and Laserlike, a web-search startup acquired by Apple in 2018. At Apple he spent six years as a principal software engineer/engineering manager building search. He was later a Member of Technical Staff at OpenAI and then xAI before co-founding River AI in 2026 with his twin brother Ievgen Soboliev and xAI co-founder Igor Babuschkin. River AI, which builds user-owned personal AI agents, raised $1.1B in August 2026.

Notes10

• Quant employment verification: CONFIRMED. The LinkedIn profile record lists a Software Engineer role at Jump Trading Group, London, 2016-2017 - an actual engineering role (not a student program or insight day). Jump Trading is independently described as a proprietary trading firm focused on algorithmic and high-frequency trading, so the employer operates in quantitative/proprietary trading. Identity is supported by one coherent profile (same name, Kharkiv applied-mathematics education, IMO/competitive-programming background, continuous career) reached from the supplied LinkedIn URL. Caveat: the specific role and dates come from the LinkedIn profile record (index-derived), not an independent primary-source confirmation; treat as index-only.Jan 2017
• River AI raised $1.1 billion led by General Catalyst and AMP PBC, announced 2026-08-11, for the company he co-founded.Aug 11, 2026
• Co-founded River AI (Palo Alto, CA) with twin brother Ievgen Soboliev and xAI co-founder Igor Babuschkin; the founding team is described as former xAI employees building user-owned personal AI agents.Jun 11, 2026
• Identity is the IMO 2008 Ukraine contestant: official spelling 'Dmytro Sobolyev', silver medal, 23 points; his career profile uses the variant spelling 'Soboliev' - two spellings of one person, not two people.Jul 2008
• Career arc is research/engineering at search-and-AI companies: Jump Trading software engineering -> Laserlike (web search/recommendation startup) -> Apple search (Laserlike was acquired by Apple in 2018) -> OpenAI -> xAI -> co-founding River AI.Sep 3, 2026
• Reported as one of 'two new top engineers' at X (twin Dima alongside Ievgen), given a mandate to use xAI's Grok to replace work done by X staff - press describes the Soboliev twins as central to X/xAI engineering.Nov 24, 2025
• Competitive-programming record ('sdya'): Codeforces international grandmaster (max 2797), TopCoder / Google Code Jam / Facebook Hacker Cup finalist across 2010-2018 - a long top-tier algorithm record consistent with the IMO background and with later search/ML engineering.Nov 2018
• X account @dsoboliev (verified) is used for River AI launches; an Aug 2026 post announced the $1.1B raise and the River API, tying the profile to the current venture.Aug 11, 2026
• Publicly discusses agent/recommendation engineering: a LinkedIn post frames applying xAI compute and Grok pretraining to 'supercharge the X Algorithm', indicating algorithmic/recommendation-systems work at X.2025
• No personal blog, portfolio, or personal website is linked from his career profile; personal web presence is the X account and LinkedIn. (A same-name frontend developer in Slovakia is a different person.)Sep 2026