What is Sidechain?
A sidechain is an independent blockchain connected to a parent chain through a two-way bridge that lets assets move between them. Sidechains have their own consensus and security model — they don't inherit it from the parent — and are often used for higher throughput at lower assurance.
Why Sidechain matters
Understanding Sidechain is part of building a solid mental model of how Bitcoin, blockchain and Web3 systems actually work. Concepts in the Concepts category sit at the foundation of the broader stack — get them right and the rest is far easier.
Learn this interactively
Reading the definition is a start. ZeroToBlock teaches concepts like Sidechain through hands-on, browser-based simulations. Build the mental model by actually using it:
- Bitcoin 101 — interactive fundamentals course
- Bitcoin Proof of Work — mining, hashing and consensus
- Browse all interactive blockchain courses
Related terms
- Bridge — A protocol that moves assets or messages between chains.
- Layer 2 (L2) — A scaling network that settles to a Layer 1.
- Blockchain — A chained, append-only ledger of blocks.
More concepts terms
- Decentralization — Distributing control across many independent participants.
- Atomic Swap — Trustless cross-chain trade using hash time-locked contracts.
- Byzantine Fault Tolerance (BFT) — A system that works even when some nodes lie or fail.
- Staking — Locking tokens to secure a network and earn rewards.
- Validator — A node that proposes and attests to blocks in PoS.
- Layer 1 (L1) — A base blockchain network with its own consensus.
- Rollup — An L2 that posts transaction data to L1 for security.
- Optimistic Rollup — A rollup that assumes validity, with a fraud-proof challenge window.
Keep exploring
Continue with the full blockchain glossary — 136 terms in total — or read the developer blog and FAQ for deeper context.