Sismo vs Gitcoin Passport

Badges as portable, verifiable assets: Badges are stored as non-transferable NFTs (ERC1155) on Polygon, making them chain-agnostic credentials. This modularity enables complex, cross-protocol reputation systems (e.g., a DeFi protocol can gate access based on a badge minted from a Gitcoin grant).

Proven in production for Gitcoin Grants: The system has secured over $50M in community-funded grants across 18+ rounds. Its scoring algorithm and stamp weights are optimized for the specific threat model of quadratic funding, making it the default choice for decentralized grant platforms and retroactive funding initiatives.

Zero-Knowledge (ZK) attestations: Users generate reusable ZK proofs from their source data (e.g., prove you hold >10 ETH without revealing address). This is critical for sybil-resistant airdrops and private governance where user anonymity is paramount. Leverages Sismo Connect for seamless app integration.

User-controlled data aggregation: The Sismo Data Vault lets users aggregate credentials across chains and accounts into one portable, private profile. This enables cross-chain reputation and complex attestation logic (e.g., "prove you own a Nouns DAO NFT AND have a Gitcoin Passport score >20").

Wide protocol adoption: Used by Optimism, Arbitrum, Base and 300+ other projects for sybil filtering. Passport's stamp system (e.g., BrightID, ENS, Proof of Humanity) provides a battle-tested, easy-to-audit reputation score. Ideal for grant programs and retroactive funding where transparency is key.

Streamlined integration: The Passport API and SDK offer a straightforward way to gate access based on a score threshold. No cryptography expertise required. This matters for hackathons, quick MVP launches, and projects prioritizing rapid user onboarding over advanced privacy features.

Higher implementation overhead: Leveraging ZK proofs and the Data Vault requires more developer lift than a simple score check. The Sismo protocol is powerful but has a steeper learning curve. This can slow down development for teams without cryptographic expertise.

Opaque scoring algorithm: The Passport score is computed off-chain by Gitcoin, creating a trust dependency. Users must reveal their connected accounts (stamps) to the scorer. This is a limitation for applications requiring fully decentralized, user-proven credentials or selective disclosure.

Zero-Knowledge Proof (ZKP) Focus: Users mint 'Badges' as ZK attestations, proving traits (e.g., 'ENS Holder', 'Gitcoin Donor') without revealing underlying accounts. This is critical for privacy-preserving applications where selective disclosure is a requirement, not a feature.

Protocol-First Architecture: Requires deeper integration (e.g., Sismo Connect, on-chain verification) versus a simple API call. This offers more flexibility but demands more engineering resources, making it less suitable for rapid prototyping or teams with limited dev bandwidth.

Plug-and-Play Sybil Defense: A single, aggregated 'Passport Score' (0-100+) from 20+ verifiers (BrightID, ENS, POAP). Used to protect over $50M+ in grant rounds. Ideal for retroactive funding, airdrops, and governance where a simple, trusted score is the primary need.

Opaque Scoring Algorithm: The scoring logic and weightings are managed by Gitcoin, creating a trust dependency. Users aggregate data into a single, non-private identity bundle. This is a limitation for permissionless, credibly neutral systems or applications requiring user data sovereignty.