link! ‒ The Unstoppable URL Shortener
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This is an unstoppable URL shortener. It allows users to store a short version of a URL, this short (often mnemonic) version can be resolved back to the long version.

The section Why? below contains more details on the distinction to traditional URL shorteners.

We built this project to illustrate how a full-stack DApp can be built with:

Smart Contract: ink! as the programming language for the contract.
Blockchain: We use the Substrate blockchain framework with it's module for smart contracts (pallet-contracts). You can use Substrate to build either standalone blockchains or parachains for Polkadot and Kusama.
Frontend: For our MVP we use the polkadot-js API with hardcoded RPC and node URLs.

In our next iteration of this MVP we want to migrate the frontend to utilize substrate-connect under the hood. In consequence the frontend would be truly trustless, there would then be no need to put trust in a server that e.g. the RPC return values are indeed what is stored on the blockchain.

Rococo Deployment

The link! contract is deployed to Rococo at the following address:

5GdHQQkRHvEEE4sDkcLkxCCumSkw2SFBJSLKzbMTNARLTXz3

Its metadata can be found here. It is upgradeable by the chain's sudo account.

🤔 Why?

Popular URL shorteners are for-profit companies, relying on them to infinitely store a URL can only be done by trusting those third parties to always adhere to their pinky promise.

In the past there have been a number of incidents where URL shorteners removed the short URL at some point for a variety of reasons: commercial interests, moral values, legal obligations, ….

We're not aware of incidents where URL shortener services maliciously decided to change the resolved URL after the fact, but it's something that can in principle be done. Importantly this could also be done without the companies intention. An attacker could modify the company database and there would be no way for a user to know that the short URL now resolves to something else.

Point being: you don't have any guarantee that the short URL will always be resolved to the same long URL. You have to trust the central service.

Blockchains allow us to build decentralized applications in a trustless manner. A central ledger ensures that you can't simply edit a value, the nodes in a blockchain network (often many thousands) have to come to consensus on this change. You don't have to trust a central entity anymore that it will always adhere to its promises. Instead you can put your trust in the underlying scientific mechanisms behind the blockchain network.

With this project we illustrate how our stack can be used to build a decentralized URL shortener where you don't have to put trust in a singular entity.