Today, we're excited to announce Ethereum Comments Protocol (ECP), a new protocol that lets anyone write posts, reply and react to them, directly onchain — at sub-cent gas fees on L2s.
Beyond putting content onchain, ECP enables new kinds of social apps via hooks, allowing communities and apps to gate who can post, charge fees, reward creators, create attention markets, create collectibles, and more, by setting their hooks smart contract, or by choosing from one from the growing library of community-created hooks.
You can try ECP live today in Interface, the first app to integrate ECP.
Build with us at ethcomments.xyz
Until today, builders have faced two options for building social features: either store content in their private cloud database, where other apps can't access it and it can be taken offline, or integrate a full-stack web3 social protocol, which requires educating users about that protocol, creating separate profiles, paying for those profiles, and maintaining the integration through updates and changes.
ECP offers an alternative path for crypto builders who want to harness the interoperability, guarantees, and composability of blockchains, without the tradeoffs of a full stack social protocol.
ECP makes the following design choices
Incrementally adoptable: Apps can integrate just what they need without buying into an entire vertically integrated identity, content, social ecosystem (No lock in) - just comments + reactions
Credibly neutral: no first party app with privileged protocol and user base access
User-invisible infrastructure: The protocol operates as infrastructure, not as a branded network that needs to be educated and evangelised to the end user
100% open source & MIT licensed: No proprietary components or privileged access, nor first party closed source apps.
Unopinionated, Permissionless & Stable APIs: Our smart contracts aren’t upgradeable. We can’t break your app or force you to refactor your app every couple of months to keep it from breaking. The content is stored directly onchain, for any developer to permissionlessly build on.
Built on Ethereum standards: Leveraging existing ecosystem tools rather than recreating them - use with ethereum accounts.
Virtually free (subcent fees to post on L2s): With the advent of low-cost L2s and L3s, on-chain social features are now economically viable in ways they simply weren't before. Posting a comment on Base via ECP costs approximately a half of a cent — and some chains subsidise gas fees entirely, enabling free, gas sponsored experiences for users.
Uncompromising UX: Users can give your app an approval to post on their behalf, at which point the onchain component becomes invisible via gas sponsored transactions.
There are several compelling reasons for apps to implement onchain comments via ECP over traditional methods:
Interoperability and data portability - Comments become part of the permanent, open record of Ethereum, allowing any application to access and display them without permission. This enables cross-platform discussions and prevents vendor lock-in.
Verifiable authenticity - Onchain comments are cryptographically signed, providing proof of who wrote what and when. This is valuable for reviews, feedback, and discussions where authenticity matters.
Composability - Comments can be programmatically referenced by other smart contracts and applications, enabling new use cases like incentivized engagement, moderation mechanisms, and reputation systems. Third party apps and services can provide distribution, spam algorithms or other infrastructure that the ethereum stack.
Censorship resistance & Permissionlessness - While apps can moderate their own interfaces, the underlying comment data remains accessible on chain, preventing permanent censorship or loss of user-generated content.
Future-proof - As the web3 ecosystem evolves, having comments onchain ensures they remain accessible even if individual applications shut down. Users retain ownership of their contributions.
ECP is one piece of what could become a more comprehensive set of social building blocks, each focused on doing one thing well rather than trying to be an all-in-one solution. Smaller, more atomic protocols give developers the choice to compose these elements as needed, choosing from available primitives that suit their needs — . Here are some examples of social primitives on ethereum that can be used with ECP
Authentication: SIWE for seamless web3 login
Identity: ENS for user profiles
Follows: Ethereum Follow Protocol for social connections
Messaging: XMTP for direct communication
Comments: ECP for threaded discussions
…many more onchain social protocol primitives that are don’t exist yet
ECP is 100% MIT licensed open source, the contracts are immutable, and is live on Base today.
We’re building the best open source toolkit for building on ECP - from indexers to SDKs to React components, to make it as easy as possible to get started building on ECP. Get started today at docs.ethcomments.xyz. We also have a no code option for embedding ECP powered comments sections into websites and blogs that you can find here.
We're talking with key ecosystem players about integrating ECP into their applications. If you're building an application or ecosystem that wants to put content onchain, we'd love to hear from you.
Next steps
Add an ECP comments section to your website or blog →
Follow us on X →
Reach out to us on telegram or XMTP →
there's another version of this blog post onchain on ECP here https://ecp-eth.github.io/md/?commentId=0xdd7c50da20ea91fbda7e9868ed880bf933d3d22eef8ff12667e1d6c96ef3ddb7&chainId=8453
Ok this is pretty cool. 👍🏾