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Arun Rajkumar, Co-founder and CTO, Atoa

Arun Rajkumar is co-founder and Chief Technology Officer of Atoa, an FCA-authorised UK payments platform for Pay by Bank and card payments. Based in Bengaluru, he leads Atoa’s engineering team building for the UK market — the open-banking APIs, developer tools, and the Atoa MCP server that lets AI assistants and agents work with Atoa’s payments. Before Atoa, he held roles at Signzy and KlearCard, the fintech acquired by Validus in 2021. He writes about engineering leadership, hiring and building payment products, and speaks about open banking and AI-native payments.

Areas of expertise

  • Open banking APIs and payment initiation (PIS/AIS)
  • Payment infrastructure and platform engineering
  • Agentic / AI-native payments (MCP server, AP2 protocol)
  • Developer tools, SDKs and API design
  • Payments security and compliance (ISO 27001, SOC 2, Strong Customer Authentication)
  • Card and Pay by Bank omni-channel payment systems

Selected work and credentials

  • Co-Founder & CTO, Atoa (FCA-authorised payment institution, FRN 1007647); co-founded with Sid Narayanan (CEO) and Cian O’Dowd
  • Leads Atoa’s Bengaluru engineering team; built the developer platform — public API, Atoa CLI, SDKs (Web, Flutter, React Native) and the hosted MCP server at mcp.atoa.me
  • Previously at Signzy and KlearCard (acquired by Validus, 2021)
  • Studied at IIM Calcutta
  • Writes on engineering & hiring: open-source coding-exam platform (DEV.to, mickyarun)

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