⛓️ Relay Chain: Coordinate Parachains

Understand how the Relay Chain provides shared security

Connect specialized blockchains to a relay chain

Relay Chain Architecture

The Polkadot Relay Chain is the heart of the network, providing security and coordination for all parachains. Unlike traditional blockchains that process individual transactions, the Relay Chain validates parachain blocks, not individual transactions.

🔑 Key Insight: Two-Layer Validation

Parachains process transactions independently (Layer 1), then produce a "proof of validity" that validators verify on the Relay Chain (Layer 0). This allows 100 parachains to process ~100,000 TPS total while maintaining shared security.

Parachain: Processes 1,000 transactions → Produces proof
Relay Chain: Validates proof (not 1,000 individual txs) → Finalizes

Three Key Roles in Polkadot

Polkadot's architecture separates responsibilities across three roles. Select each to understand their unique function:

🛡️
Validator
Validates parachain blocks and secures Relay Chain
Minimum Stake
2,000,000 DOT minimum (~$10M)
Expected Reward
~15% APY
Responsibilities:
  • Validate parachain state transitions
  • Participate in GRANDPA finality
  • Produce Relay Chain blocks
  • Vote on governance proposals

Block Production Simulation

Watch how the Relay Chain coordinates block production across multiple parachains. Each parachain produces blocks independently, then validators finalize them together.

Ready to Simulate
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GRANDPA Finality

Polkadot uses GRANDPA (GHOST-based Recursive Ancestor Deriving Prefix Agreement) for finality. Unlike Nakamoto consensus which requires 6+ confirmations, GRANDPA achieves deterministic finality in seconds.

❌ Probabilistic Finality

Bitcoin/Ethereum: Wait 6+ blocks (~60 minutes Bitcoin, ~15 minutes Ethereum) for "probably final"

Still technically reversible with 51% attack

✅ Deterministic Finality

Polkadot: GRANDPA finalizes after 2-3 seconds. Mathematically impossible to reverse.

Requires 2/3+ validators to collude (economically infeasible)