Polkadot Launch:
Parachain Rollout

Parachains are the last piece of core functionality to be delivered as outlined in the Polkadot whitepaper, and will allow Polkadot to realize its scalable multi-chain architecture. After a period of testing, optimization and auditing, parachains will be ready for launch on Polkadot, and can be enabled via on-chain governance. Once parachains are live, the community will determine which additional features and network upgrades should be added over time.

  • Testnet Rollout

    Parachain functionality will roll out first for testing and bug fixing on parachain testnets like Rococo. Once we’re confident the code is ready, we’ll open registration for parachain teams to test their own chains, including interaction with other chains via XCMP-lite. Once we’ve developed and tested the final elements of core functionality for parachains and Cumulus - approval voting, distribution, availability recovery, and disputes - the Polkadot codebase will officially be feature complete.

  • What’s next?

    When we’re confident testnet parachains are running smoothly, a vote to enable parachain onboarding to Kusama, including slot auctions and crowdloans, will be submitted via on-chain governance.

  • Current Stage: Kusama Rollout and Slot Auctions

    As a live network with real economic incentives, Kusama will serve as an additional proving ground for parachains, allowing the community to observe network effects and conduct further testing and optimizations. Kusama governance will first vote to enable parachain functionality via runtime upgrade. After that it can vote to begin slot auctions and to add any common-good parachains.

    Parachain Slot Auctions

    Parachain slot leases will be allocated via non-permissioned candle auctions. After the first auction on Kusama, there will be a new auction taking place roughly every two weeks. After each auction, the winning parachain will be deployed to the network at the beginning of its lease period. Auctions will continue from here on a rolling basis as more slots become available and previous leases expire.

  • What’s next?

    Once all audits are completed and parachains are running smoothly on Kusama, Polkadot’s community can enable parachain functionality, deploy the first public-good parachains and begin slot auctions on Polkadot via on-chain governance.

  • Polkadot Rollout and Slot Auctions

    Polkadot governance will first vote to enable parachain functionality via runtime upgrade. After that, it can vote to begin slot auctions and to add any common-good parachains.

    Parachain Slot Auctions

    Parachain slot leases will be allocated via non-permissioned candle auctions. After the first auction on Polkadot, there will be a new auction taking place roughly every two weeks. After each auction, the winning parachain will be deployed to the network at the beginning of its lease period. Auctions will continue from here on a rolling basis as more slots become available and previous leases expire.

  • Future Upgrades

    With parachains live on Polkadot, the network’s launch will officially be complete according to its original vision and design. Future upgrades, including full-featured XCMP and parathreads, can be enabled via network governance after the code has been fully developed, tested, benchmarked and audited. What the future holds for Polkadot from here is up to the community.

What happened before parachain rollout?

Check out the full Polkadot launch roadmap to find out how we got to where we are today.

See Launch Roadmap
FAQs
  • What are parachains? keyboard_arrow_right

    Parachains are the diverse individual layer-1 blockchains that run in parallel on Polkadot, connected to the Polkadot Relay Chain and secured by the Relay Chain’s validator set. The key to Polkadot’s scalable multichain architecture, parachains share in and benefit from the security, scalability, interoperability and governance of Polkadot. Polkadot’s cross-chain composability allows any type of data or asset to be sent between parachains, opening up a host of new use cases and applications. Parachains can also connect to external networks such as Bitcoin and Ethereum using cross-network bridges. Parachains can have a wide variety of designs and can be optimized for specific use cases. Parachains connect to the Relay Chain by leasing a parachain slot via parachain slot auctions, by being granted a slot by Polkadot governance as a common good chain, or by connecting as a parathread.

  • Based on theoretical computing constraints, the current goal and expectation is that we will have approximately 100 parachain slots available on Polkadot, though potential future optimizations (such as nested relay chains) may allow us to further increase this number. However, it will take some time before Polkadot mainnet fully supports 100 parachain slots, and they are likely to be added to the system slowly over time. Not all of these slots will be allocated via parachain slot auctions (upon successful governance vote to begin auctions), as some will be used for governance-enabled common goods parachains (aka system chains) and parathreads.

  • Parachain slot leases will be secured according to a two-week candle auction. In the beginning, one auction will take place roughly every two weeks. After this, auctions will continue on a rolling basis as more slots become available and previous leases expire. Detailed information about slot auctions is coming soon.

  • Individual parachain slots can only be leased for a period of up to two years (in six-month increments). At the conclusion of the lease, the slot will go back up for auction and the team will need to bid for a slot again if they wish to retain one. Parachain slots are fungible, so to avoid any downtime in connectivity and minimize the risk of losing a subsequent auction, teams can bid on and secure an adjacent slot before their current lease period ends. Teams can also choose to connect to Polkadot as a parathread.

  • Parachain teams may or may not choose to use Polkadot’s crowdloan mechanism to help back their parachain slot lease bid. To participate in a crowdloan, users agree to lock up a portion of DOT or KSM for the duration of the parachain slot lease period, after which they are unlocked. The details of individual crowdloan campaigns and the process for joining them will be determined and communicated by the respective parachain teams.

    Important: Polkadot’s native crowdloan mechanism does not require users to send DOT or KSM from their own wallet/account to participate in a crowdloan. All crowdloan contributions are handled by the crowdloan module’s logic where a campaign is identified by an index, not by an address. Legitimate teams conducting a crowdloan natively on Polkadot (via Polkadot.js) will not ask you to send tokens to an address to participate. However, some teams may choose to conduct a crowdloan campaign using other mechanisms or platforms. In this case, be sure to never send tokens to anyone you don’t trust. Always check teams’ official channels to find out how to participate.

  • The cost of leasing a parachain slot will purely be a function of market supply and demand, so it’s difficult to give any meaningful estimate as to what the bid requirement will be. However, it's important to realize that the actual cost of a parachain slot is not the same as the size of the parachain bid. Since parachain bonds are returned at the conclusion of the slot lease, the actual cost of running a parachain is best characterized as the opportunity cost of not staking those DOT for the duration of the lease period. The need to run collators is an additional but relatively minor cost. In general, for high throughput applications we expect parachains to be more economical than building with smart contracts or building a standalone blockchain.

  • We expect parathread functionality to launch some months after parachains are live. As with any network upgrade, it will need to be enabled through on-chain governance.

  • Some interoperability features are already live on the Rococo parachain testnet with XCMP-lite, which allows parachains to exchange messages (e.g. assets and arbitrary logic) via the Relay Chain. Full XCMP will allow direct parachain-to-parachain messaging without needing to route messages through the Relay Chain, and is still under development. Full XCMP will need to undergo testing, benchmarking and auditing before being enabled on Polkadot, once a significant number of parachains are live.

  • Common-good chains are parachains viewed as a common-good, in the sense that they will benefit the entire network. Common-good chains are determined by network governance, which can vote to allocate the chain an empty slot on the Relay Chain, thereby bypassing the auction process. Common-good chains can be thought of as system-level chains and public utility chains that provide functions and benefits to the network that builders can tap into.

  • Parachain teams can bid for leases in 6-month increments from a minimum of 6 months to a maximum of 24 months. After the slot lease period is over, the slot will go up for auction again and the team will need to bid again if they wish to retain a slot (or connect as a parathread). Parachain slots are fungible, so to avoid any downtime in connectivity and minimize the risk of losing a subsequent auction, teams can bid on and secure an adjacent slot before their current lease period ends.

  • Parachains considered a common-good for the entire network can be added to a slot via governance vote (See above).

  • You are welcome to join Polkadot‘s official Discord channel or Element chat. For all governance related discussions, join the Polkadot Direction Element chat or visit Polkassembly. Validators can join the Polkadot Validator Lounge on Element. Or email us: support@polkadot.network.
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