Index Ventures has led a $13 million seed round for Marker, a London-based startup developing an AI-native word processor designed to support, rather than replace, the writing process. The funding round includes participation from LocalGlobe, Betaworks, Radical Ventures, Tiny VC and Otherwise Fund, along with angel investors such as the founders behind Google Docs, Slack and Hugging Face. Marker positions itself as a “reimagined word processor” built on the idea that AI should write with you, not for you, functioning as a super-thesaurus, built-in fact-checker and conversational editor. Early testers have used Marker for blogs, business papers, memos, Substack posts and novels. The company’s co-founders, Jon Steinback and Ryan Bowman, bring experience from AI and publishing; Steinback previously led brand and creative at DeepMind and held roles at Facebook and Google, while Bowman spent two decades building tools for writers at Nature, the Financial Times and literary and talent agencies. Funding from the seed round is expected to be used to grow Marker’s product development team, enhance its underlying writing model infrastructure and scale early-access programs. The company is emerging from stealth with this round and opening up early access to a larger group of users.