###### Abstract
However, many manuscripts remain unexplored due to these obstacles. To meet the growing demand for historical analysis, tools must serve a large user base simultaneously while providing the essential security features for effectively prohibiting direct access of the end users to the documents themselves and/or the infrastructure that hosts them. Academic institutions with limited computational resources require efficient services that balance workload and infrastructure cost-effectively [22]. The research inquiry that necessitates a response is as follows:  
Q1: What kind of information fusion framework could facilitate the provision of HTR services with minimal computational burden? Q2: What is the optimal quantity of parallel end users that can be effectively accommodated by this framework? Q3: Can an HDP and/or HTR system expand in order to support more manuscript collections and/or additional user applications as part of a growing demand for manuscript accessibility without compromising its performance? The primary objective of the present study is to tackle these inquiries through a concentrated effort on an expandable and adaptable information fusion (IF) tool, with the ultimate aim of streamlining the transcription procedure under the uDoc.tS initiative, an IF architecture developed to process and transcribe Greek handwritten texts from the Byzantine era. The project focuses on text recognition and aims to automatically transcribe handwritten text of historically significant manuscripts to digitized text, thus rendering it accessible to the average student or researcher and enabling its further automated processing. The uDoc.tS information system features a machine learning-based system for the automated transcription of handwritten text to digitized text and a complete suite of image processing tools that can aid in automated word detection of an image. It also features an intuitive user interface that allows the uDoc.tS information system to be used on manuscript images already uploaded to the system, as well as on manuscript images that can be uploaded to the system by the user. Despite uDoc.tS' focus being on Greek handwritten text, the presented architecture is designed to be language and period-agnostic, allowing for the support of various algorithmic models and Graphical User Interfaces in a scalable manner. The central element of the IF architecture, known as the gateway API, is presented in detail. The gateway API facilitates the efficient delivery of request services between the information system's end users and its services and tools, such as transcription tools, databases, etc., by acting as a request manager and workload balancer among different entities. It allows for the seamless integration and synchronization of the system's tools and software packages, ensuring smooth operation and access only to authorized applications and services. This type of architecture is believed to offer support to researchers, institutions, and organizations like archives, libraries, and museums. To ensure the proper functioning of the information system, tools, and individual applications, various use-case scenarios are tested. The performance of the system is evaluated by analyzing critical parameters such as its response under different load conditions and user numbers, the execution time of various processes, and the corresponding memory usage. Many more manuscripts have been produced for the \(\upmu\)Doc.tS information system, which focuses on other aspects of it, such as its transcription tools and methods [23]. The paper is organized as follows: Section 2 outlines the information fusion system's architecture. Although all systems' main functionalities are briefly discussed, the primary focus is on providing a detailed description of the API Gateway. Section 3 explains the methodology used for validating and verifying the data fusion architecture, while Section 4 showcases the relevant results.