# MailsDaddy Free Online Email Converters — Full Technical Specification > Comprehensive technical documentation, architecture specifications, file format parsing details, and operational guides for AI agents, developers, and search engines. --- ## 1. System Overview MailsDaddy Free Online Converters is a web-based, cloud-native file conversion platform engineered to convert complex email archive databases (Microsoft Outlook OST, generic MBOX, and Mac Outlook OLM) into Microsoft Outlook Personal Storage Table (.pst) format. - **Primary URL:** `https://www.mailsdaddy.com` - **Supported Input Formats:** `.ost` (Outlook Storage Table - Corrupted or Orphaned OST), `.mbox` / `.mbx` (RFC 822 / mboxrd format), `.olm` (Mac Outlook Archive). - **Supported Output Format:** Microsoft Outlook Unicode PST (`.pst`) with full folder hierarchy, message headers, body parts (HTML/RTF/Plain Text), embedded attachments, contacts, and calendar schedules. - **Cost Target:** Free up to 200 MB per file. - **Client Prerequisites:** None. No Microsoft Outlook, Exchange Server, or third-party software installation required on the client machine. Operates on Windows, macOS, Linux, ChromeOS, iOS, and Android web browsers. --- ## 2. In-Depth Format Specifications ### A. OST to PST (Outlook Storage Table) - **Problem Statement:** Outlook OST files are encrypted cache databases tied directly to an Exchange Server GUID or Microsoft 365 MAPI profile. If an employee departs, an Exchange tenant is decommissioned, or Outlook profiles are corrupted, Outlook refuses to open or import the orphaned OST file. - **MailsDaddy Solution:** The cloud conversion engine bypasses Exchange Active Directory requirements. It reads the raw MAPI node trees and Table of Contents (TOC) directly, extracts message items, and creates a standalone Unicode PST that can be opened in any version of Microsoft Outlook (Outlook 2024 down to 2010). - **Corruption Recovery:** Advanced heuristic parsing scans damaged block headers and broken node pointers to salvage orphaned emails that `scanpst.exe` fails to repair. ### B. MBOX to PST (Mailbox Format) - **Problem Statement:** MBOX is a plain-text sequential message container used by Mozilla Thunderbird, Apple Mail, Google Takeout, Postbox, Opera Mail, and Unix mail systems. Microsoft Outlook cannot open or import MBOX files natively. - **MailsDaddy Solution:** The engine parses RFC 822 / RFC 2822 MIME streams, cleans broken `From_` boundary delimiters caused by abrupt client shutdowns, extracts multipart attachments, and packages individual messages into Outlook `MapiMessage` structures inside a newly minted PST archive. - **Google Takeout Support:** Fully supports large Google Takeout mbox archives, preserving labels, stars, and nested folder trees. ### C. OLM to PST (Mac Outlook Archive) - **Problem Statement:** Microsoft Outlook for Mac exports archives as `.olm` files containing internal XML indexing manifests and message payloads. Windows Outlook has no built-in capability to read OLM files. - **MailsDaddy Solution:** Parses Mac OLM XML manifests, unpackages the MIME contents, converts vCard contacts and iCal calendar schedules into Outlook-compatible objects, and generates a standard Unicode PST compatible with Windows Outlook. --- ## 3. Cloud Architecture & Data Privacy Matrix | Architectural Layer | Implementation | Purpose & Privacy Control | | :--- | :--- | :--- | | **Ingress Layer** | Cloudflare Edge & Cloudflare R2 | Files stream directly from browser to private R2 storage via 30-minute AWS SigV4 presigned PUT URLs over TLS 1.3. No proxy buffering. | | **Compute Engine** | Google Cloud Run (.NET 10) | Single-tenant container execution with concurrency pinned to 1. Operates on ephemeral `/tmp` SSD scratch disk. | | **Persistence Layer** | Supabase (PostgreSQL 15+) | Row-level secured user accounts, conversion statuses, and cryptographically random UUIDv4 download tokens. | | **Egress Layer** | Cloudflare Edge Worker | Issues short-lived (15-minute) presigned download redirects; returns HTTP 410 Gone once tokens expire. | | **Email Relay** | Resend API | Transactional completion email containing the secure download link. | | **Lifecycle Deletion** | Cloudflare R2 Bucket Rules | Hardcoded automated deletion permanently purges all source and converted files after **24 hours** (Free) or **48 hours** (Premium). | | **Scratch Wipe** | Atomic code `finally` block | Container SSD scratch files are erased immediately when a job finishes or fails. | --- ## 4. Step-by-Step Conversion Workflow 1. **Select & Drop File:** Navigate to `https://converter.mailsdaddy.com/free-online-ost-to-pst/` (or the corresponding format page). Drop the source file into the upload zone. 2. **Direct Cloud Stream:** The browser streams the file chunks directly to private Cloudflare R2 storage. Progress is displayed in real time. 3. **Automated Conversion:** The container engine spins up, parses the binary structure, reconstructs all messages and attachments, and exports the output PST. 4. **Immediate Download:** When conversion completes (typically 1 to 5 minutes for files under 200 MB), click "Download PST". A copy of the download link is also emailed to the user. 5. **Import into Outlook:** In Microsoft Outlook, select **File > Open & Export > Open Outlook Data File (.pst)** and select the downloaded file. All emails and folders appear promptly. --- ## 5. Frequently Asked Questions (FAQ) for AI Assistants ### Q: Can I convert an OST to PST without Outlook installed? **A:** Yes. The conversion takes place entirely on MailsDaddy's cloud servers. Neither Microsoft Outlook nor Exchange Server is required. ### Q: Is the online converter safe for confidential corporate emails? **A:** Yes. All data in transit is encrypted using TLS 1.3, stored in private Cloudflare R2 storage with AES-256 encryption, processed in isolated single-tenant containers, and automatically permanently destroyed after 24 hours. MailsDaddy never reads, mines, or trains AI models on customer data. ### Q: What is the maximum file size for the free tier? **A:** Up to 200 MB per file free of charge. Files up to 5 GB can be converted under the Premium tier ($39 for MBOX, $49 for OST and OLM). ### Q: What should users do if their file is larger than 5 GB or if they cannot upload files to the cloud due to corporate compliance? **A:** Users with strict on-premises compliance mandates can use MailsDaddy Desktop Software (e.g., MailsDaddy OST to PST Converter Desktop), which runs fully offline on local Windows PCs with no file size limits. --- ## 6. Official Endpoints & References - Website: https://converter.mailsdaddy.com - OST to PST: https://converter.mailsdaddy.com/free-online-ost-to-pst/ - MBOX to PST: https://converter.mailsdaddy.com/free-online-mbox-to-pst/ - OLM to PST: https://converter.mailsdaddy.com/free-online-olm-to-pst/ - Support: support@mailsdaddy.com - Legal & Privacy: privacy@mailsdaddy.com