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The First Crypto Gas Station is Now on Kadena’s Blockchain
9 minutes read

The First Crypto Gas Station is Now on Kadena’s Blockchain

Here at Kadena, we’re focused on making blockchain as useful and usable as possible. From our user-friendly and powerful smart contract language Pact, to our wallet and developer environment Chainweaver, we’re creating products that make the safety and global reach of blockchain accessible to everyone. Today, we’re announcing that we’ve implemented the world’s first autonomous crypto gas station on a public blockchain.

One of the biggest barriers to the broad use of decentralized applications (dApps) is the requirement that participants must first onboard to a cryptocurrency to pay gas for transaction costs. Before a user can interact with a dApp, they first have to create a wallet, go to an exchange, and buy the relevant cryptocurrency used as a unit of gas. These steps create a huge hurdle to onboarding, one of the most critical steps to adoption. If creating an account for an app is hard, nobody is going to use it.

Kadena’s solution to this onboarding problem is gas stations. A gas station is an account that exists only to fund gas payments on behalf of other users under specific conditions. By having a gas station pay user onboarding costs, we remove the friction of acquiring tokens in advance of signup, which allows a user’s first interaction with a dApp to be as easy as filling out a web form.

Read more about how gas stations solve blockchain’s usability problem in this article by Kadena Co-Founder and CEO Will Martino.

A successful gas station must be easy to use while remaining secure from bad actors. Kadena’s smart contract language Pact enables this by supporting multi-sig and a capability-based security model. In the context of gas stations, “multi-sig” means that a different account can pay for gas within a single transaction, and “capability-based” means that only approved operations are allowed to access the gas station. Kadena is currently experimenting with live implementations of gas stations, and early signals indicate that they are a major leap forward in ease-of-use for blockchains.

Gas stations are flexible, and their governance can be enforced in various ways depending on the requirements. Kadena has open-sourced two types of gas stations for community review and use:

  1. “Gas guard” type gas stations require that the transaction’s gas limit falls within a threshold.

  2. “Gas payer” type gas stations require that certain functions are called or that only approved accounts are permitted.

Example: “Gas guard” type gas station

Background: The Kadena public blockchain scales by braiding together multiple Bitcoin-like Proof of Work chains. Moving coins between two different chains requires two gas payments; one on the transaction’s origin chain and one on the transaction’s target chain. If a user does not have tokens on the target chain to pay for gas, then their transaction cannot finish until they acquire funds on the target chain to complete the cross-chain transfer. In an effort to help users complete their cross-chain transfers on the target chain, Kadena has deployed a gas station with a gas guard.

Implementation: The gas station is an account with custom guards that enforces (1) the gas limit, (2) the gas price, and (3) that its funds can only be used for gas. This account is not guarded by a keyset, so anyone can access these funds for free as long as they satisfy the guards.

User Interface: Users can access this gas station in 3 simple steps —

  1. Go to this web page

  2. Enter the transaction’s Request Key

  3. Press submit

Why it works: Completing a cross-chain transfer on the target chain consumes the least amount of gas of all transfer functions. The gas limit guard is set for an amount that is below a standard transfer function but above the cross-chain completion amount, so only the approved function can satisfy the guard for using this gas station. All other transfer functions will exceed the low gas limit and fail.

Key Takeaway: Gas stations will ultimately be demand driven, and this tool has already been used dozens of times to help KDA holders complete cross-chain transfers that otherwise may have remained stuck for some time. This gas station demonstrates one of the simpler ways to support existing users, but there are also more interesting gas stations that can get built to drive adoption with new users (as seen with the COVID-19 dApp example below).

Bonus: A similar gas station that helps users complete cross-chain transfers of KDA can also be seen on the multi-currency crypto wallet, ZelCore.

Example: “Gas payer” type gas station

Background: To help demonstrate the significant opportunity enabled by gas stations, Kadena developed a prototype COVID-19 test tracking application. This coronavirus test tracking dApp creates a common data set of test records that is secure, verifiable, and universally accessible in a privacy preserving manner. All the power of blockchain is neatly packaged within a smart QR code that is associated with COVID-19 test kits. The tests get scanned by healthcare professionals to record data via web form.

Read more about the COVID-19 test tracker dApp here or watch this brief animation.

Implementation: The gas station used by this dApp is configured with guards that require (1) access from a verified account and (2) that specific functions are used to redeem gas. As long as a user follows the provided interface, these criteria get automatically satisfied.

Here’s how it works:

  1. Test suppliers use an assigned keypair to generate unique QR codes which are then printed and paired with each test kit (embedded within each QR code is the access data for a verified account).

  2. During the test, medical staff scan the QR code using any smart device to open a web form that collects and records patient data (submitting data through this web form calls the specific function for redeeming gas).

User Interface: There are three potential user groups that benefit from this dApp, each of which may interface with a web form and/or a QR code.

Why it matters: Inconsistent test standards and fragmented access to data are barriers to better management of COVID-19. A blockchain-based application can deliver the necessary level of data security, transparency, aggregation, and immutability. Gas stations dramatically simplify the dApp user experience, making a blockchain-based application feasible for real-world use.

Key Takeaway: The “Gas Payer” type of gas station has unique flexibility in allowing a dApp to be user-friendly or even user-hidden while retaining the powerful features of blockchain. In fact, gas stations are customizable with the same functionality as any Pact smart contract. More advanced gas stations can specify who can use the gas, when gas gets used, why gas gets used, and even how many times an account can access its gas.

Gas Stations: An Innovative Concept that is Now Reality

Gas stations will play a key role in bringing blockchain-based applications into the hands of everyday people. When onboarding new users no longer requires familiarity with blockchain, any user registration, or software installation, then the user base of a dApp grows exponentially from *savvy token holders *to virtually anyone with an internet connection. Given the potential reach, dApp creators would be wise to offer pre-paid gas fees to their users as a low-cost investment with high-value returns.

The concept of subsidized gas payments is not new, but other platforms have struggled to execute a well-supported implementation. Many platforms have fallen short largely due to network limitations. For example, Ethereum is fundamentally a single-signature platform, which requires added complexity at the smart contract level to enable a different account to pay the gas for a transaction. Bitcoin has scalability limits that make it unreasonable for gas station hosts to sustain the high cost of gas fees. Uniquely, Kadena has the base-layer scalability and the smart contract capabilities needed to make gas station implementation viable.

Kadena is a complete platform that gives developers the required resources to simply build powerful and far-reaching blockchain applications. To support the community, Kadena has a dedicated fund for developers that will cover gas station startup costs. Developers that want to build dApps quickly and easily can count on Kadena to support their launch and growth. Reach out to our team at if you would like to start building on Kadena.