Outlook Add-in for Email-to-PDF Archiving and Document Management
Overview of Our Client
The client needed a convenient way to transfer HR-related email communications and attachments from Microsoft Outlook into an established document management workflow. Employees had to be able to prepare emails and files for archiving or distribution without leaving their email client.
The solution also needed to preserve relevant email information, support different attachment formats, and protect sensitive data throughout document processing and transfer. To accommodate different working environments, the client required two versions: a desktop add-in built with VSTO and a cross-platform add-in based on the Office JavaScript API.
- Platforms: Microsoft Outlook Desktop and Outlook Web
- Industry: HR / Document Management
- Time Frame: 2–3 months
Challenge
HR teams kept important correspondence in Outlook, but the client’s document management platform accepted only structured, archive-ready files with metadata. Moving emails there by hand was slow and error-prone. The add-in had to solve several technical problems:
- Two Outlook environments. Some employees used classic Outlook for Windows, others Outlook on the web, so one add-in technology could not cover everyone.
- Mixed content. Email bodies, Word, Excel, PowerPoint, and PDF attachments each required a different conversion path, chosen by MIME type.
- Signed documents. Converting a digitally signed PDF would invalidate the signature, so the add-in had to detect signatures and convert only unsigned files to PDF/A-1B.
- Archive-ready output. Files had to meet the PDF/A-1B standard for long-term storage and carry sender and email metadata.
- Secure access. Documents with personal HR data had to reach the platform only through authenticated requests, using OAuth 2.0 with PKCE.
Project Overview
SCAND designed and architected the VSTO add-in, developing its core document-processing functionality, authentication, and custom Outlook interface. We also built a cross-platform version using the Office JavaScript API.
We built two versions on purpose. The VSTO add-in covers classic Outlook for Windows and gives full access to the desktop object model and local files. The Office.js version runs in Outlook on the web and other supported Outlook clients, where VSTO and COM add-ins are not supported. Both share the same processing workflow and user experience.
The add-ins converted email content and supported Office attachments into PDFs using Aspose libraries. Email PDFs included sender names and email addresses, while unsigned PDFs were enriched with metadata and converted to PDF/A-1B for archiving.
For security, we implemented OAuth 2.0 Authorization Code flow with PKCE, with access tokens validated on both the client side and the server side, and configurable authorization scopes. We also implemented configurable manifest generation and analyzed the Docker image used to deploy the backend web service for document processing and request handling for security vulnerabilities.
Solution
The completed solution consisted of two Outlook add-ins that integrated email and attachment processing with the organization’s document management workflow.
Users could prepare email communications and supported attachments for archiving or distribution directly from Outlook. The document-processing workflow converted relevant content into PDF, preserved sender information, and applied PDF/A-1B preparation to unsigned PDF documents where required.
The solution combined Outlook-integrated interfaces, configurable deployment settings, authenticated access, and consolidated document submission. This provided the organization with a structured way to transfer email-based records into its document management platform while supporting both desktop and cross-platform Outlook environments.
Core Application Capabilities
- Dual Outlook Add-in Versions: Provided a VSTO add-in for Outlook desktop and a cross-platform version built with the Office JavaScript API.
- Email-to-PDF Conversion: Converted email bodies into structured PDF documents containing the sender’s display name and email address.
- Attachment Processing: Identified attachments by MIME type and processed supported Word, Excel, and PowerPoint documents.
- PDF Digital Signature Checks: Checked PDF documents for digital signatures before applying archival conversion.
- PDF/A-1B Preparation: Converted unsigned PDFs to PDF/A-1B after adding the required metadata.
- Metadata Preservation: Associated converted documents with relevant email metadata for document management.
- Consolidated Document Submission: Sent converted PDF files and email metadata together in a single HTTP request.
- OAuth 2.0 Authentication: Implemented Authorization Code flow with PKCE, with access tokens validated on both the client side and the server side.
- Configurable Authorization: Supported user-defined authorization scopes.
- Manifest Generation and Configuration: Supported add-in manifest generation using configurable parameters and deployment settings.
- Outlook-Integrated Interface: Provided custom interface components for configuring settings and managing document processing within Outlook.
- Backend Service Security Assessment: Analyzed the Docker image used to deploy the backend web service for security vulnerabilities.
User Workflow
- Select Email Content: The user accessed an email in Outlook and initiated the document-processing workflow.
- Inspect Email and Attachments: The add-in identified the email content and attachment types to determine the applicable processing steps.
- Convert Email to PDF: The email body was converted into a structured PDF with the sender’s display name and email address.
- Process Attachments: Supported Office documents were converted using the configured document-processing libraries.
- Check PDF Signatures: Existing PDF files were checked for digital signatures, and unsigned documents were prepared in PDF/A-1B format with the required metadata.
- Authenticate the User: The add-in used OAuth 2.0 Authorization Code flow with PKCE, while access tokens were validated on both the client side and the server side before protected resources were accessed.
- Submit Documents and Metadata: The converted files and associated email metadata were submitted to the document management platform in a single HTTP request.
- Configure the Add-in: Administrators or users could configure supported manifest parameters, authorization scopes, and deployment settings.
Technology Stack
To support Outlook integration, document conversion, secure authentication, and cross-platform operation, we used the following technologies:
Platforms
- Microsoft Outlook Desktop
- Outlook Web
Desktop Development
- C#
- .NET Framework
- Windows Forms
- VSTO
Cross-Platform Development
- Office JavaScript API
- JavaScript
- TypeScript
Frontend
- React
- HTML
- CSS
Document Processing
- Aspose libraries (Aspose.Email, Aspose.PDF, Aspose.Slides, Aspose.Words, Aspose.Cells)
Email and Attachment Processing
- MIME type detection
- Email body extraction
- Office document conversion
PDF Archival
- PDF/A-1B conversion
- Digital signature checks
- Document metadata processing
Authentication
- OAuth 2.0 Authorization Code flow with PKCE
- Client-side token validation
- Configurable authorization scopes
API Integration
- HTTP requests
- Combined document and metadata submission
Configuration and Deployment
- Add-in manifest generation
- User-defined parameters
- Deployment settings
Container Security
- Docker image vulnerability analysis
Results
HR employees now archive an email with its attachments in a few clicks without leaving Outlook. Signed PDFs stay legally valid, unsigned files arrive in the archive in PDF/A-1B format with full sender metadata, and every transfer goes through authenticated access. The client got the same workflow for classic Outlook and Outlook on the web from a single project.
The key business outcomes included:
- Reduced manual effort: Simplified the preparation and submission of email correspondence and attachments, reducing repetitive work for employees.
- More consistent document handling: Standardized document preparation and metadata transfer, helping reduce inconsistencies during archiving and distribution.
- Improved workflow integration: Enabled employees to initiate document processing directly from Outlook, keeping the process within their existing work environment.
- Flexible deployment: Delivered desktop and cross-platform add-in versions to support different Outlook environments.
Core Team
- Full-Time Developer (1 FTE): Implemented the add-in’s core functionality, including Outlook integration, document-processing workflows, user interface components, and security mechanisms.
- Project Manager: Managed project planning, timelines, priorities, and communication with stakeholders.
- Solution Architect: Defined the technical architecture and ensured the solution met functional and technical requirements.
- Technical Lead (Part-Time): Guided implementation decisions, reviewed code quality, and coordinated technical activities.
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