Summary: CUBID is best cataloged as proof-of-personhood and sybil-resistance identity middleware rather than as a simple login SDK, reputation widget, or single-app KYC flow. In this pass, the clearest first-party evidence came from the CUBID introduction docs, the API v2 reference, the terminology glossary, and the Cubid Passport repository. Together those materials describe a cross-app identity system built around reusable identity “stamps,” app-scoped user IDs, ecosystem-wide scoring and blacklist propagation, selective disclosure, webhook-driven trust updates, and optional wallet generation for downstream apps. The key distinction is that CUBID is packaging a reusable coordination layer for proving unique humans across many apps without forcing those apps to share a universal public identifier.
What it does:
Lets apps create app-scoped user_id records tied to one identity credential such as email or phone through POST /api/v2/create_user
Returns sybil-relevant state such as whether the user is new to the app, whether the same human appears to be posing as a new user, and whether the submitted credential is already blacklisted
Builds reusable identity profiles from “stamps” such as email, phone, social accounts, blockchain accounts, and proof-of-personhood systems
Maintains a cross-app score intended to estimate how likely a user is to be a unique real human, while allowing apps to use either CUBID’s default scoring logic or their own formula
Propagates identity-strengthening or weakening events across the ecosystem through APIs and webhooks without requiring apps to share raw personal data with one another
Can generate an app-specific EVM public key for a user and store the corresponding key material inside the CUBID-managed wallet layer for gas-sponsored or abstracted UX flows
Demonstrates adjacent product directions through Cubid Passport, including passwordless login, stamp collection from Gitcoin Passport, walletless account creation on NEAR, and minting proof-related state onchain as an SBT
Key claims:
The introduction says CUBID is a decentralized identity management and Sybil attack prevention protocol that uses cryptographic techniques, zero-knowledge proofs, and collaboration between apps to verify that users are real while preserving privacy
The same introduction frames CUBID as a cross-app scoring protocol where apps share insights, receive webhook updates when identities are strengthened or weakened, and can respond to blacklisting or recovery events
The docs say users control selective disclosure through reusable identity “stamps,” so different apps can validate different facets of identity without receiving unnecessary information
The API reference says POST /api/v2/create_user can create an app-scoped user, associate it with a CUBID credential, and return is_new_app_user, is_sybil_attack, and is_blacklisted to help apps detect account farming or multi-account behavior
The same API reference explicitly recommends using CUBID’s user_id as the core application identifier when proof-of-personhood or bot defense is business-critical, which is a strong clue that CUBID is meant to be infrastructure rather than an optional analytics sidecar
The terminology glossary says CUBID uses app-scoped user IDs specifically to avoid cross-site tracking, describes stamps as weighted identity attributes, and says proof-of-personhood scores quantify trust in the uniqueness of the user’s identity rather than general social reputation
The API reference also documents POST /api/v2/pk/fetch_evm_public_key, which generates one app-specific EVM account per user, showing that CUBID is not only an identity layer but also an embedded wallet-control surface for apps that want low-friction blockchain onboarding
The Cubid Passport repository shows a concrete flow combining passwordless login, Gitcoin Passport stamp collection, walletless NEAR account creation, SBT minting, and private-key export, reinforcing the product’s positioning as identity-plus-wallet onboarding infrastructure
Whitepaper: No canonical standalone CUBID whitepaper or litepaper surfaced in this pass. The clearest current source of truth was the docs corpus and official GitHub repositories, especially the introduction, API reference, terminology glossary, and Cubid Passport materials; see ../whitepapers/cubid-primary-sources-2026-05-04.md.