Atum has emerged from stealth with a $13.5 million seed round led by Variant to develop the Open Payments Network, a coordination layer that connects payment initiators with settlement providers that move funds. PayPal Ventures, Abstract Ventures, Road Capital, Mirana Ventures, First Commit and Credibly Neutral also participated. The San Francisco-based company says it does not issue currency, operate a blockchain, take custody of funds or act as a transaction counterparty. Payment requests specify the asset a sender uses and the asset a recipient receives, while settlement providers submit real-time quotes and the selected provider completes settlement across the required rails. Smart contracts hold funds until delivery is verified. Atum also supports AI-agent payments through x402 and MPP. Founder and CEO Pete Cooling previously led Visa's crypto product team and was involved with the Linux OpenWallet Foundation.