CommerceBlock is a blockchain infrastructure company that provides a highly flexible and scalable open-source environment for companies to tokenize their real-world assets and securities across public and permissioned networks. Utilizing the CommerceBlock toolkit, developers can deploy highly customizable sidechains, enabling novel contexts in which businesses can manage their process flows and fulfill contractual obligations with the reliability and support they have come to expect from modern SaaS providers. CommerceBlock‘s public blockchain based infrastructure enables the distribution, exchange and storage of tokenized assets and securities through the execution of smart contracts. We have created an open-source ecosystem utilizing sidechains together with an attestation service (MainStay) to combine the immutability and security of public blockchains with the flexibility of private blockchains. To achieve this, we have extended the sidechain protocol Elements with easy-to-use libraries for issuing assets, constructing complex trade flows, enforcing multiparty escrow and producing trusted regulatory audit trails.