SAP Master Data Integration has been described as a multi-tenant cloud service for master data integration. It provides a consistent view on master data across a hybrid landscape. It is a part of the
SAP Cloud Integration Strategy.
But what does it mean? It means it will bring uniformity for master data objects across different SAP Cloud Solutions by using the
SAP One Domain Model (ODM), a unified domain model for business objects distributed throughout different SAP applications. For years now, System Integrators have used Point to Point (PoP) integrations for master data between the systems in a complex landscape making it a nightmare for maintenance. It will reduce the integration effort by configuring the integrations between all instances in one place and also orchestrating master data from one place.
SAP Master Data Integration (MDI) uses SAP One Data Model for out-of-the-box SAP integration and synchronize business objects across Enterprise Cloud landscape.
Please refer to Open SAP course -
open.sap.com/courses/mdi1/ for detailed concepts and understandings.

Guiding Principles
Ref: open.sap.com/courses/mdi1/
But how is this done? SAP Master Data Integration (MDI) and SAP Master Data Orchestration (MDO) are 2 of the Services in
SAP Business Technology Platform.

SAP BTP Services
Instance: SAP Master Data Integration

Instance for SAP Master Data Integration
Subscription: SAP Master Data Orchestration

Subscription for SAP Master Data Orchestration
MDI uses SAP One Domain Model. SAP One Domain Model is a single and coherent domain model for SAP's intelligent suite, spanning the digital core and all SAP Cloud line of business applications. With its harmonized domain model for objects that are distributed throughout the different applications, SAP One Domain Model provides a basis for a consistent view on master data across the entire, hybrid landscape. By mapping objects to a central domain model, SAP One Domain Model enables applications to synchronize with each other although they speak different languages, aligns configuration and transactional data, and sets the foundation for integration and extension scenarios.

SAP One Domain Model
Ref: open.sap.com/courses/mdi1/
SAP One Domain Model Explorer
SAP API Business Hub

SAP One Domain Model Explorer - CostCenter
Create Service Key for MDI instance on BTP:

Create Service Key

Service Key
The Service key will be used to generate credentials for the MDI instance.
View Credentials for MDI:

View Credentials
Using Postman for Connecting Clients:
Create a POST request
https://mdi-test-xxxxxxxxx.authentication.eu10.hana.ondemand.com/oauth/token

OAuth 2.0
Create a GET Request
https://one-mds.cfapps.eu10.hana.ondemand.com/v1/odm/3.0.0/sap.odm.finance.costobject.CostCenter/eve...

CostCenter
https://one-mds.cfapps.eu10.hana.ondemand.com/v1/odm/2.1.1/sap.odm.businesspartner.BusinessPartner/e...

BusinessPartner
https://one-mds.cfapps.eu10.hana.ondemand.com/v1/odm/2.2.0/sap.odm.businesspartner.BusinessPartnerRe...

BusinessPartnerRelationship
SAP Master Data Orchestration enables you to handle distributed and federated sets of master data in a heterogenous landscape. MDO is a sub-part of MDI. SAP Master Data Orchestration as operational cockpit and UI on SAP Master Data Integration.

SAP Master Data Orchestration
Ref: open.sap.com/courses/mdi1/
Create Subscription for SAP Master Data Orchestration in BTP:

Subscription for SAP Master Data Orchestration
SAP Master Data Orchestration Fiori application:

SAP MDO Fiori Apps
Types of Distribution Mode: Push and Pull
REST API: Both Push and Pull Mode cane be used.
SOAP API: Push Mode can be used.

Types of Distribution Mode
Ref: open.sap.com/courses/mdi1/
Distribution of Master data: Provider and Consumer instances

Distribution of Master data
Ref: open.sap.com/courses/mdi1/
Create a Pull Based Distribution Model for Business Partner:
Pull Based Distribution Model
Create a Push Based Distribution Model for Business Partner:

Push Based Distribution Model
Manage Distribution Models:

Distribution Models
Manage Business Object Types:

Business Object Types
Conclusion: MDI provides reliable real-time replication in a hub-and-spoke approach. This allows every business application to have its own copy of the relevant master data.

SAP Master Data Integration Service on SAP BTP
Ref: open.sap.com/courses/mdi1/
Please check my other blog posts.
Mapping different domains in SAP Master Data Governance to SAP S/4HANA processes | SAP Blogs
Understanding SAP MDG in a Traditional way | SAP Blogs
Using SAP BTP for Master Data Governance with Fiori Tiles | SAP Blogs
Simple steps to start RISE with SAP S/4HANA Cloud | SAP Blogs
Demystifying One Domain Model w.r.t Master Data Objects | SAP Blogs
Data Journey from SAP MDM to SAP MDG | SAP Blogs
Exposing master data as ODATA service from S/4 HANA on-premise | SAP Blogs
A Simple illustration for SAP Data & Analytics | SAP Blogs
Data Visualization simplified for SAP Data Consultant
Best Regards,