---
title: Shared Definitions
description: Reusable type definitions shared across Certified lexicons.
---

# Shared Definitions

`app.certified.defs`

Common type definitions used across the certified ecosystem. Currently defines the `did` type, which represents a Decentralized Identifier.

The `did` type is used throughout the certified and hypercerts lexicons to reference accounts and actors. It ensures consistent formatting and validation of DIDs across all record types.

For the full schema, see [`app.certified.defs`](https://github.com/hypercerts-org/hypercerts-lexicon/blob/main/lexicons/app/certified/defs.json) in the lexicon repo.