What is the HDA file format?
.hda is a document template file associated with the HotDocs automated document assembly application. Template files are used to generate documents using predefined formatting and layout settings. The template package is discarded after the document has been assembled - no permanent local copy of the component files is retained on the end user's machine.
HotDocs is an application for automated document generation. The program uses various template file types - including .hda, .hpt, and .hpd - to create customized documents with variable text and formatting. HotDocs is compatible with Microsoft Word and Corel WordPerfect as word-processor back-ends, and produces output viewable in Adobe Reader. It is a popular document management solution for companies that use standardized documents required to comply with internal rules and procedures.
An .hda (Auto-Assemble) file compresses the HotDocs template together with all its component files - clause libraries, answer file templates, and variable datasets - into a single distributable package. This self-contained packaging is designed for delivery over a network, intranet, or web server without leaving local copies behind.
HotDocs was originally developed by Matthew Bender & Company and is currently owned and actively maintained by Mitratech, which offers both a desktop and a cloud-hosted (HotDocs Cloud) version of the platform.
Security & safety
RISK: MEDIUMHDA files contain document automation logic (conditional rules, variable substitution) that executes when opened in HotDocs. While not executable code in the traditional sense, the template logic could theoretically be crafted to produce misleading output documents. Source trust matters - only open HDA files from known, trusted legal or organizational sources. No known CVEs for HotDocs HDA processing.
Format details
in a nutshell- Houdini Digital Asset (HDA) - SideFX Houdini uses .hda extension for Houdini Digital Assets - reusable node networks in the 3D VFX software; completely unrelated to HotDocs.
Programs that open HDA files
Windows1 app
HotDocs (Mitratech)
Paid Open HotDocs Assemble or HotDocs Developer; pass the HDA file - HotDocs unpacks it and starts the assembly interview automatically.
HotDocs Cloud (Mitratech)
Paid Enterprise cloud deployment of HotDocs; HDA templates can be published to HotDocs Cloud for browser-based assembly. Technical details
deep spec| Container format | Proprietary compressed package (HotDocs internal format; likely ZIP-based; no public specification) |
| Contents | HotDocs template (`.hpt`), clause libraries, answer file templates, variable datasets, and referenced assets |
| Compression | Yes - all component files are compressed into a single distributable package |
| Assembly lifecycle | Unpacked to a temporary folder at assembly time; temporary files deleted after document assembly completes |
| Distribution purpose | Network, intranet, or web delivery of templates without leaving permanent local copies on client machines |
| Compatible word processors | Microsoft Word and Corel WordPerfect (as back-end document engines); output viewable in Adobe Reader |
| Operating system | Windows (HotDocs desktop); web-based assembly via HotDocs Cloud/Server |
| Encryption | None documented in the HDA container itself |
| Current developer | Mitratech (acquired from LexisNexis; originally Matthew Bender & Company) |
| Format status | Active - HotDocs is an actively maintained enterprise platform as of 2026 |
| Related formats | `.hpt` (HotDocs component template), `.hpd` (component file), `.rtf` and `.docx` (output documents) |
| Primary use sector | Legal, financial, and government organizations using standardized document automation workflows |
| Released | Early 2000s (HotDocs version unknown; format used since HotDocs 2005 era) |
| Latest version | Current - HotDocs is actively maintained by Mitratech (as of 2026) |
| Specification | help.hotdocs.com |
HDA conversions
Community Q&A
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