> For the complete documentation index, see [llms.txt](https://elder-2.gitbook.io/elder-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://elder-2.gitbook.io/elder-docs/architecture/quick-overview-cosmos-sdk-and-cometbft.md).

# Quick Overview: Cosmos-SDK and CometBFT

### Cosmos-SDK

Cosmos-SDK is a framework for building blockchain applications in the Cosmos ecosystem. It's designed to simplify the process of creating custom blockchains that can interoperate with one another.

#### Key Features

* **Modularity:** Developers can build blockchain applications using pre-built modules like staking, governance, or custom modules tailored to specific needs.
* **Interoperability:** Through the Inter-Blockchain Communication (IBC) protocol, chains can communicate and transfer assets or data securely.
* **Flexibility:** Offers the ability to define custom business logic in Go, allowing for highly specialized blockchains.
* **Community:** Backed by a vibrant developer community contributing to its ecosystem.

### CometBFT (formerly Tendermint Core)

CometBFT is a **battles-tested** Byzantine Fault Tolerant (BFT) consensus engine that ensures that all nodes in a network agree on the state of the blockchain. It's the underlying consensus mechanism for Cosmos SDK-based blockchains.

#### Key Features:

* **BFT Consensus:** Uses a variant of Practical Byzantine Fault Tolerance for fast finality and network security.
* **Modular Design:** Separates the consensus mechanism from the application layer, allowing for reuse across different applications.
* **State Sync:** New nodes can quickly sync to the latest state without downloading the entire history, enhancing scalability.
* **Light Clients:** Supports light client proofs for efficient blockchain verification on resource-constrained devices.

### Together in Action:

* **Cosmos Hub:** The first blockchain built with Cosmos-SDK using CometBFT for consensus, acting as the center of the Cosmos ecosystem.
* **Interoperability:** Chains built with Cosmos-SDK can leverage CometBFT's consensus for secure cross-chain transactions via IBC.

Cosmos-SDK and CometBFT are key technologies enabling developers to build interoperable, scalable, and secure blockchains. They provide a foundation for innovative blockchain networks, integrating IBC for communication and surpassing traditional development hurdles.