What is Chainweb? — Kadena's Multichain Architecture Explained

The 20-chain architecture

Kadena's production network runs 20 parallel chains, indexed 0 through 19. Each chain:

• Runs the Pact smart contract language
• Produces blocks at the same protocol cadence
• References specific peer chains in the braided graph
• Maintains its own state (account balances, contract data)
• Can interact with peer chains via native cross-chain transfers

Mining is performed across all 20 chains simultaneously. Block rewards distribute across chains. Total network throughput is approximately 20× single-chain throughput, with the trade-off that some applications (those that require strict sequential ordering across all transactions) need to consider chain-to-chain coordination.

The braided graph

Chainweb's distinctive design feature is the "braided" connection pattern between chains. Each chain references three peer chains; those peers in turn reference others; the resulting graph has dense connectivity that any attacker would need to subvert across multiple chains simultaneously to attack the network as a whole.

The mathematical analysis of this design (published in academic papers by the original Kadena team) shows that the security properties scale with the number of chains and with the connectivity of the braid. The 20-chain configuration is the production parameter set; the architecture supports other chain counts in principle.

A practical consequence: Kadena's security argument is different from a single-chain network. Bitcoin's security is in its cumulative hashrate concentrated on one chain. Kadena's security is in the difficulty of subverting the braid across many chains simultaneously.

Block production

Each Kadena chain produces blocks at the protocol-defined cadence. Block times average approximately 1.5 seconds per chain. Across 20 chains, the network produces roughly 13 blocks per second in aggregate.

Mining is performed using the Blake2s_256 hashing algorithm (Kadena variant). The current production hardware is ASIC (Antminer KA3, Goldshell KD-series). See Kadena mining.

The protocol's difficulty adjustment maintains target block times in response to changes in network hashrate.

Cross-chain transfers

Moving KDA (or any Kadena-based asset) between Kadena chains is a native protocol operation. The flow:

1. Initiate the transfer on the source chain (debit the sending account).
2. Wait for the source chain to produce a block including the debit.
3. Generate an SPV (Simple Payment Verification) proof from the source chain.
4. Submit the SPV proof to the destination chain along with a credit instruction.
5. Destination chain credits the receiving account.

This entire flow takes approximately one to two minutes in practice (multiple block times across both chains plus proof generation). Modern Kadena wallets (Kadena Wallet included) automate the SPV proof and broadcast steps so that the user experience is a single "Send" action.

Older wallets and developer tools sometimes expose the SPV proof as a manual step. Both approaches work; the automated experience is preferable for most users.

Chainweb-EVM — the forward-looking 5-chain extension

Chainweb-EVM is the planned addition of 5 EVM-compatible chains alongside the existing 20 Pact chains. The total network would be 25 chains: 20 Pact-based + 5 EVM-based. The architectural design preserves the braided graph properties while adding execution-environment diversity.

Status as of May 2026:

• Testnet: operational
• Mainnet: not launched; timing community-led and uncertain after the Foundation dissolution

For full Chainweb-EVM detail see Kadena EVM.

Comparison to other multi-chain approaches

Ethereum + L2s. Ethereum mainnet is one chain; L2s (Optimism, Arbitrum, Base, etc.) are separate chains that depend on Ethereum for finality and data availability. Kadena's chains are part of one network with shared security from merged mining; they don't depend on any external chain.

Avalanche subnets. Avalanche supports custom subnets that are independent chains with their own validator sets. This is more flexible than Kadena's fixed Chainweb but trades off the unified security model.

Polkadot parachains. Polkadot's relay chain coordinates parachains that each run independent state. Conceptually similar to Chainweb in some respects; technically very different (Polkadot uses Proof-of-Stake).

Sharding (planned for various chains). Sharding splits a single chain into pieces processed in parallel. Kadena's Chainweb predates most shard implementations and takes a different conceptual approach (parallel chains with explicit cross-chain mechanics rather than implicit sharding).

Each multi-chain design has trade-offs. Kadena's distinctive choice is parallel chains with braided security and protocol-native cross-chain transfers.

The November 2025 hard fork

A community-coordinated hard fork occurred in early November 2025, shortly after the Foundation dissolution. The fork addressed protocol-level questions raised during the transition period and was coordinated through community channels rather than through Kadena LLC.

The chain has continued operating without controversy since the fork. Specifics of the fork's changes are documented in Chainweb node software release notes available through community channels.