ioTube v5 Cross-Chain Bridge – Now Supports Polygon & Web3!

Introducing ioTube v5 with full Web3-compatiblity and two-way token swaps between IoTeX ↔ Ethereum, BSC, and now Polygon. Get started at!

ioTube v5 Cross-Chain Bridge – Now Supports Polygon & Web3!

Introducing ioTube v5, a cross-chain bridge that enables bi-directional exchange of tokens between IoTeX, Ethereum, Binance Smart Chain, and now Polygon! We are excited to take this major leap in expanding the footprint of IoTeX to three of the largest blockchains in the world and broadening the utility of IOTX and XRC20 tokens. In addition to Polygon support, ioTube v5 is fully Web3-compatible, meaning you can use both MetaMask and ioPay Mobile to access ioTube v5.

“Collaboration is the key to excellence in today’s market. IoTeX going cross-chain to Polygon will bring real world benefits to the ever-growing digital world, and make NFTs more relevant to this novel philosophy.” — Sandeep Nailwal, Polygon Co-founder
A sleek new interface for ioTube v5 with dark mode (new!)

ioTube v5 is a major upgrade to our already sophisticated cross-chain bridge. With support for 20+ assets from Polygon, Ethereum, and BSC, IoTeX is now one of the most connected blockchains in the industry! Even better, we have fully open-sourced ioTube v5 on GitHub and made it compatible with Web3 wallets (e.g., MetaMask, ioPay Mobile) for an incredible user experience. This major cross-chain bridge update includes the following features:

  • Polygon Support: transfer tokens with ultra-low fees between IoTeX and Polygon. ioTube v5 supports a variety of Polygon assets, including: MATIC, WETH, WBTC, DAI, USDT, USDC, SUSHI, QUICK, CYC
  • Web3-compatibility: use your favorite Web3 wallet (e.g., MetaMask, ioPay Mobile) to access ioTube v5 anytime, anywhere
  • Enhanced Performance: ioTube v5 is faster than ever with ultra-low fees enabling users to bridge assets cross-chain with confidence
  • Cross-chain Explorer: see real-time analytics of all cross-chain transactions in addition to other analytics such as total TVL, chains, and assets
See all cross-chain transactions in the new ioTube Explorer.

⭐️ Ready to get started? Check out our step-by-step tutorials on how to convert tokens between Polygon-IoTeX, Ethereum-IoTeX, and BSC-IoTeX. For any questions, please reach out to an Admin on Discord or Telegram.

⭐️ IoTeX & Polygon: learn more about our partnership with Polygon.

New ioTube URL: access ioTube at our new URL:

The IoTeX Cross-Chain Ecosystem

IoTeX is quickly becoming the most connected blockchain in the industry. With cross-chain integrations and two-way token swaps now available between IoTeX and Ethereum/Polygon/BSC, users can find greater utility of their digital assets by exploring Dapps across multiple blockchains with the same tokens. For example, IOTX + XRC20 token holders can transfer tokens to three of the top blockchains in the world and utilize their tokens in an ever-growing number of Dapps, DEXs, farms, and more. What blockchain do you want to see IoTeX connect to next?

IoTeX is the most connected blockchain in the world – what top network will we connect to next?

ioTube v5 — Overview & Architecture

ioTube utilizes multiple smart contracts on both the origin/destination blockchain to enable cross-chain token transfers. It starts when a user deposits assets into a “cashier contract” on Chain A, which is an event that is observed by multiple witness nodes. These witnesses verify this event and send a signature to the relayer network, which aggregates all signatures and instructs a “validator contract” on Chain B to mint the same amount of tokens that were deposited on Chain A.

The ioTube v5 architecture is composed of the following contracts:

  • WitnessList: stores the list of active witnesses
  • TokenList: stores the list of whitelisted tokens
  • TokenSafe: stores the tokens deposited to token cashier, and these stored tokens are used to transfer to recipients by transfer validator
  • MinterPool: holds the minter authorities of all mintable tokens
  • TokenCashier: accepts token/coin deposits and emit a receipt for each deposit
  • TransferValidator: validates witness signatures and then withdraws tokens from token safe to recipients.

For depositing assets, the TokenCashier contract validates the following:

  • Checks if the asset is listed and active
  • Checks if the amount is within the maximum limits
  • Checks if the asset is a proxy token (e.g., ioETH on IoTeX is a proxy token)
  • If proxy, burns it and create a receipt; if not proxy, deposits it into the TokenSafe.

Once a witness detects a deposit, they will sign an attestation and send it to the relayer, which collects attestation from witnesses and submit them to TransferValidator.

For minting (i.e., issuing corresponding assets), the TokenValidator contract ensures:

  • The asset being converted is whitelisted and active via TokenList
  • The transfer has attestations from at least two-thirds of all witnesses
  • If so, the contract mints proxy tokens to transfer tokens to the given recipient.

That’s it! After tokens are converted between IoTeX, Ethereum, BSC, and Polygon they may be traded on respective decentralized exchanges, including: mimo (IoTeX), Quickswap (Polygon), Uniswap (Ethereum), and PancakeSwap (BSC). Stay tuned for even more cross-chain integrations to leading blockchain networks in the near future and see our open-source ioTube code here.

About IoTeX

Founded in 2017, IoTeX is an EVM-compatible blockchain platform to fuel the Internet of Trusted Things, an open ecosystem where humans and machines can interact with guaranteed trust and privacy. IoTeX envisions a future where everyday people can own and control their smart devices, as well as the data and value they generate. Backed by a global team of 30+ top research scientists and engineers, IoTeX combines blockchain, decentralized identity, and secure hardware to enable user-owned IoT devices and networks. By connecting the physical and digital worlds, IoTeX will empower the future machine economy and redefine the trillion-dollar IoT industry.

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