A scalable, interoperable & secure network protocol for the next web

Any type of data across any type of blockchain

Polkadot is a network protocol that allows arbitrary data—not just tokens—to be transferred across blockchains.

This means Polkadot is a true multi-chain application environment where things like cross-chain registries and cross-chain computation are possible.

Polkadot can transfer this data across public, open, permissionless blockchains as well as private, permissioned blockchains.

This makes it possible to build applications that get permissioned data from a private blockchain and use it on a public blockchain. For instance, a school's private, permissioned academic records chain could send a proof to a degree-verification smart contract on a public chain.

Network Glossary

Polkadot unites a network of heterogeneous blockchains called parachains and parathreads. These chains connect to and are secured by the Polkadot Relay Chain. They can also connect with external networks via bridges.

Connecting the dots

Relay Chain

The heart of Polkadot, responsible for the network’s shared security, consensus and cross-chain interoperability.


Sovereign blockchains that can have their own tokens and optimize their functionality for specific use cases.


Similar to parachains but with a pay-as-you-go model. More economical for blockchains that don’t need continuous connectivity to the network.


Allow parachains and parathreads to connect and communicate with external networks like Ethereum and Bitcoin.

Consensus Roles


Secure the Relay Chain by selecting trustworty validators and staking dots.


Secure the relay chain by staking dots, validating proofs from collators and participating in consensus with other validators.


Maintain shards by collecting shard transactions from users and producing proofs for validator.


Monitor the network and report bad behavior to validators. Collators and any parachain full node can perform the fisherman role.

Governance Roles

Council Members

Elected to represent passive stakeholders in two primary governance roles: proposing referenda and vetoing dangerous or malicious referenda.

Technical Committee

Composed of teams actively building Polkadot. Can propose emergency referenda, together with the council, for fast-tracked voting and implementation.

Built with the best technology

Polkadot’s relay chain is built with Substrate, a blockchain-building framework that is the distillation of Parity Technologies’ learnings building Ethereum, Bitcoin, and enterprise blockchains.

Polkadot’s state machine is compiled to WebAssembly (Wasm), a super performant virtual environment. Wasm is developed by major companies, including Google, Apple, Microsoft, and Mozilla, that have created a large ecosystem of support for the standard.

Polkadot’s networking uses libp2p, a flexible cross-platform network framework for peer-to-peer applications. Positioned to be the standard for future decentralized applications, libp2p handles the peer discovery and communication in the Polkadot ecosystem.

The Polkadot runtime environment is being coded in Rust, C++, and Golang, making Polkadot accessible to a wide range of developers.

Processing transactions in parallel

Parachains are specialized blockchains that connect to Polkadot. They will have characteristics specialized for their use cases and the ability to control their own governance.

Interactions on parachains are processed in parallel, enabling highly scalable systems.

Transactions can be spread out across the chains, allowing many more transactions to be processed in the same period of time.

Current method:
Single transaction


Polkadot method:
Multi parallelized transactions


Groundbreaking Technology

Polkadot is solving many of the problems that have held back blockchain technology so far — all in one place, without compromising.

A better security model

In both Proof-of-Work and Proof-of-Stake systems, blockchains compete with each other over resources to secure their networks, and blockchains are easily attacked until they develop a significant community to support their network.

Polkadot takes a different approach by letting blockchains pool their security, which means that the blockchains' security is aggregated and applied to all.

By connecting to Polkadot, blockchain developers can secure their blockchain from day one.

Transparent on-chain governance

Updates to the protocol happen fork-free via transparent on-chain voting, so protocol development never stalls due to the lack of a clear process. The relay chain uses a sophisticated governance mechanism that is designed to establish a transparent, accountable and binding process for resolving disputes and upgrading the network.

DOT tokens are used to participate in governance decisions, including tabling proposals, voting, and bonding.

Parachains are free to design their own governance mechanisms, allowing for maximum freedom without affecting other parachains.

Learn more about Polkadot’s governance
GRANDPA: a trustworthy consensus algorithm

Polkadot uses its original GRANDPA (GHOST-based Recursive Ancestor Deriving Prefix Agreement) consensus for a more secure and resilient network.

Under good network conditions, GRANDPA can finalize blocks nearly instantly. Under bad network conditions, like a network partition, GRANDPA can finalize large quantities of blocks (theoretically millions) at once when the partitions resolve.

Learn more about GRANDPA.


Polkadot development is on track to deliver the most robust platform for security, scalability, interoperability, and innovation. Polkadot will launch the genesis block in mid-2020 with one relay chain and several parachains. Then the network will ramp up to about 100 parachains.

  • PoA

    Web3 Foundation will launch Polkadot in Proof of Authority mode. During this time, most users will be able to:

    Claim tokens from their Ethereum contract,
    Stake tokens and declare their intent to validate or nominate.

    Validators will also be able to set their Session keys in preparation for Proof of Stake, and Web3 Foundation will be able to use the Sudo key to manage the chain and enable more features.

    Advancing to the Next Phase

    Once the network is running smoothly and has a sufficient number of well staked validators, we will enable Nominated Proof of Stake with a Sudo call to change eras, and therefore perform the first validator election.

  • NPoS

    During Nominated Proof of Stake, the network will run with a decentralized set of validators. During this phase, Web3 Foundation will use Sudo to increase the number of validators in the set.

    Advancing to the Next Phase

    Once Web3 Foundation is confident that the network is working well - no slashing due to client issues, functioning validator elections - the Sudo key will issue a runtime upgrade that enables Polkadot's governance system.

  • Governance and Removing Sudo

    With Polkadot's governance system enabled, it can elect the first Council and Technical Committee and start accepting public proposals. While the Sudo key might still be needed for a few operations, governance can take over most of the chain's decisions. Once Sudo is removed, root calls will only be dispatchable via governance.

    Advancing to the Next Phase

    With a Council and Technical Committee in place, Sudo will be removed. Without Sudo, Polkadot is fully in the hands of the token holders. One of the first features they will enable is token transfers with a runtime upgrade.

  • Enable Balance Transfers

    Polkadot allows balance transfers.

    Advancing to the Next Phase

    To enable remaining functionality, Polkadot's governance will need to pass one (or a series of) runtime upgrades.

  • Enable Core Functionality

    Once governance enables parachain auctions and XCMP, Polkadot will have a fully functional Relay Chain. Where it goes from here is up to the token holders.

What are teams building on Polkadot? Just a few examples:

Smart contract chains with WebAssembly smart contracts (Edgeware, Charred Cherry testnet)

Data curation networks that connect all file storage chains into curated data sets (Ocean Protocol)

Oracle chains that make off-chain data available to all contracts on the Polkadot network (ChainLink)

Identity chains that link accounts to a persistent identity and enable access to other parachains through fewer accounts (Speckle OS)

Financial chains that allow you to hold all your assets in one portfolio, including via bridges to Bitcoin, Ethereum, Bitcoin Cash, Litecoin and ZCash (ChainX, Katallassos)

Internet of Things chains that set IoT standards for machine-to-machine communication (MXC Protocol)

Zero Knowledge privacy chains, or bridges to existing ZK-snarks chains (e.g. Zerochain)

File storage chains that incentivize storing data on-chain

Bridge to Ethereum, allowing Ethereum smart contracts to interact with the Polkadot network

Want to get started? Build on Polkadot