Skip to main content


As RelationService aims to build comprehensive personal identity graphs, incorporating both on-chain and off-chain data to provide a holistic view of an individual’s digital presence.The Graph Database is the most important technology behind, aiming to supporting a full range of identity queries and social use cases. Graph Databases focus on relationships between data, making them a better option when dealing with complex relationships between intertwined data stored in multiple tables.

What is a graph database?

A graph database is a database that focuses on relationships, i.e. Something — is related to — Something else.

  1. It is a class of NoSQL databases
  2. Stores relationships, reflecting entity-to-entity relationships
  3. Uses directional-based nodes to represent data, rather than rows and columns in a table

It looks like the below:

According to the Graph, there are some concept we need to know when we using the graph database to build the identity graph

  • Vertices represent entities or instances. In NextID, vertices usually represent an identity or smart contract that interact with some accounts (e.g.Twitter account, Ethereum account, etc)
  • Edges define the relationships between vertices. (Two identities proven to belong to the same one, the accounts that hold a NFT, the account who interact with a smart contract)
  • Neighbors describe the other vertices that near to a vertex
  • Traversal refers to the process of visiting each vertex in a graph with some conditions

Graph Database in RelationService

In RelationService, we defined two type of Vertices

  • Identity: e.g.Twitter account, Ethereum account
  • Contract: a contract object on a specific chain

four type of Edges

  • Proof: represent a bi-directional relation (e.g.a Twitter account and an Ethereum account that bonded in ProofService)
  • Hold: usually represent Identity "hold" an asset (eg: an account hold a NFT)
  • Resolve: refer to the relation between the domain service and account (eg: ENS)
  • Relation: record static info between two identities

With Graph Databases, accessing related nodes becomes intuitive. Based on the data structure defined above, one can retrieve an individual identity graph, the accounts holding the same NFT collection, or those interacting with a particular smart contract by traversing the graph. Data can be extracted from the specified Edges and Vertices, tailored to your specific conditions.

some query examples for reference