Last update: January 26, 2024

Overview

This document is for crypto custodians looking to integrate with Metamask Institutional (MMI).

MMI provides a customized client library that supports custodian APIs. This document is a guide to the API a custodian must have in order for it to be usable with MMI.

What is Metamask Institutional?

An institutional Web3 platform that provides unrivalled access to decentralised applications (dApps) across all EVMs. The Metamask Institutional extension is a fork of Metamask with extended features that include:

• Organizational account management.
• Message and transaction signing using an external custodial wallet instead of the built-in personal MetaMask HD wallet.

MMI is an unlisted extension and access will be given to users who go through an onboarding process.

How it works

• A customized custodian API creates transactions with users’ Ethereum accounts, accepting arbitrary transaction parameters.

Basic custodian requirements

• Authentication via a refresh token and access token mechanism.
• Provide the three API endpoints specified in API Overview.
• A UI for approving and signing transactions that is accessible to the custodian’s users
• The ability to sign transactions and messages
• Manage nonce and gas
• Broadcast transactions
• Must be able send webhooks
• Support the customer proof mechanism

Get in touch

We can guide you through this process. Please get in touch.