The Cosmos SDK is a secure, open-source framework for building application-specific blockchains and decentralized ledgers. It is well suited for permissioned and Proof-of-Authority (PoA) blockchain networks, as well as public Proof-of-Stake (PoS) systems, giving teams full control over protocol logic, governance, security, and customization.As the business logic layer of the Cosmos stack, the Cosmos SDK provides a fully customizable foundation for building blockchains from customizable modules that define how a chain behaves, from accounts and transactions to tokenization, compliance, and custom application logic.Built on one of the longest-running blockchain stacks, the Cosmos SDK combines an open-source codebase with proven consensus via CometBFT and native interoperability through IBC. The architecture of the Cosmos SDK enables high throughput, fast finality, and strong security boundaries, enabling a seamless experience for developing purpose-built blockchains.
At its core, the Cosmos SDK is designed to give developers full flexibility across the entire blockchain stack. Teams can build and customize blockchains from the ground up, across core protocol logic, execution models, governance, and interoperability. Business logic can run natively at the protocol level, be exposed through modular components, or be extended with optional virtual machine layers, depending on the needs of the application.The Cosmos SDK is interoperable by design. Chains built with the SDK can communicate with other blockchains via IBC while maintaining independent execution and security.The customizability of the Cosmos SDK also applies to its consensus-agnostic design. Developers can pair the SDK with consensus engines such as CometBFT or adopt modular execution and settlement architectures using other frameworks, depending on their performance and security requirements.
Blockchains built with the Cosmos SDK are composed of interoperable modules, each responsible for a specific piece of functionality such as accounts, transactions, governance, tokenization, or compliance logic. These modules are built on top of the SDK’s base application framework, which provides the shared execution environment that allows modules to operate together as a cohesive blockchain.Developers can use predefined open-source modules or build their own modules tailored to their application’s requirements. Custom modules allow teams to focus on implementing their business logic rather than low-level blockchain infrastructure. By composing and extending modules, developers can build decentralized chains and ledgers that are optimized for performance, security, and long-term maintainability without reinventing the wheel.The SDK’s base layer handles core concerns such as message routing, module lifecycle orchestration, and interaction with the underlying consensus engine. It defines clear boundaries between modules by isolating their state into independent stores, while providing secure, well-defined interfaces for cross-module communication. This structure allows modules to operate and evolve independently without compromising the safety of the overall system.While SDK modules define how application logic is composed within a chain, the Cosmos SDK also supports modularity at the broader stack level. At this level, modularity refers to the ability to assemble a blockchain from interchangeable layers and components. Execution logic is defined by SDK modules, while consensus, networking, and data availability can be provided by external systems such as CometBFT or modular frameworks.For example, a team might build a Cosmos SDK application using CometBFT for consensus, where the chain itself serves as both the execution and settlement layer. Alternatively, developers can extend or replace parts of the stack to support specialized architectures, custom modules, or experimental designs. This flexibility allows chains to evolve alongside their application and operational needs.
A common development paradigm in blockchain ecosystems is the use of general-purpose virtual machine chains, where applications are deployed as smart contracts on top of a shared execution environment. While this approach is well suited for some use cases, it can impose constraints around performance, customization, and protocol-level control.Application-specific blockchains offer a different model. An application-specific blockchain is a blockchain or decentralized ledger with the ability to run custom business logic at the protocol or chain level. With the Cosmos SDK, developers can tailor execution logic, fee models, governance rules, and state transitions directly at the protocol level, enabling greater flexibility and performance.Learn more about application-specific blockchains.
While the Cosmos SDK enables native, chain-level application logic by default through modules, it also allows for the use of smart contracts. Developers can add a virtual machine layer—such as Cosmos EVM—on top of their SDK-based blockchain to support Ethereum-compatible smart contracts and tooling, or choose other VM layers.
The Cosmos SDK uses a capabilities-based security model to enforce strict boundaries between modules. Rather than granting broad access to shared state, modules are given only the specific capabilities they require, making it easier to reason about authority, permissions, and potential attack surfaces.This design improves the security and composability of complex blockchain applications. For a deeper dive into this model, see the Object-Capability Model.
Cosmos Enterprise is a comprehensive enterprise subscription designed for teams operating production-grade Cosmos-based blockchain networks. It combines hardened protocol modules, on-premises and managed infrastructure components, and direct access to the engineers building the Cosmos technology stack.Cosmos Enterprise is built for organizations that require reliability, security, and operational confidence as they scale critical blockchain infrastructure in production environments.Learn about Cosmos Enterprise →
