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Brandon Thomas is at it again. The developer who cloned Adobe’s Creative Cloud suite using AI has now dropped open-source versions of Microsoft Office’s core apps — and the crypto and tech world is paying attention.
Why It Matters
The release of open-source clones of Microsoft Office applications by Brandon Thomas highlights the growing trend of leveraging AI to create accessible alternatives to established software, potentially disrupting traditional software markets. As developers increasingly favor languages like Rust for their performance advantages, this initiative could foster greater innovation within the tech community and encourage competition, particularly in sectors where proprietary software dominance persists. Furthermore, the open-source nature of these tools may attract wider adoption, especially among startups and developers seeking cost-effective solutions.
Thomas published three tools on GitHub: WordCraft, GridCraft, and DeckCraft. They mirror Word, Excel, and PowerPoint, in that order. All three are written in Rust, a language developers love for its raw speed and its ability to prevent memory bugs. They run on Windows and macOS. And crucially, they’re released under MIT and Apache 2.0 licenses — meaning anyone can pick up the code, modify it, and even use it commercially. No strings.
Twelve thousand GitHub stars on WordCraft alone. That’s not nothing.
Where Each App Actually Stands
These aren’t finished products. Thomas is pretty upfront about that. WordCraft handles Word’s native .docx format and covers roughly 60% of Word’s features — it’s still in alpha. GridCraft, the Excel clone, supports 513 worksheet functions and sits at about 50% readiness. DeckCraft, the PowerPoint alternative, is the furthest along: 79% of PowerPoint’s features covered, with basic functionality hitting 93%.
So DeckCraft is probably the most usable of the three right now. GridCraft is the rawest. WordCraft sits somewhere in the middle, though its roadmap calls out specific gaps — better page layout alignment with Word, improved stability, native printing support. Those aren’t small fixes. They’re the kind of things that separate a demo from something a professional can actually rely on day to day.
Still, 513 Excel functions is a serious number. That’s not a toy.
The AI Engine Underneath
Thomas built all three apps using Anthropic’s Claude. Specifically, he leaned on Claude Opus 5.5, which launched in September and carries competitive pricing for processing input and output tokens. That cost structure matters — it’s part of what makes rapid AI-assisted development like this financially viable for an individual developer working outside a big corporate team.
But the AI angle goes deeper than just how Thomas built the apps. Each clone is designed to interact with AI agents through something called the Model Context Protocol. Basically, an AI agent can execute tasks — building charts, formatting documents — without the user lifting a finger. That’s a meaningful differentiator from older open-source office suites. LibreOffice and OpenOffice.org, both long-standing alternatives to Microsoft Office, don’t have that kind of native AI integration baked in at the architecture level. Thomas’s apps were designed with it from the start.
It’s a different philosophy. And it’s probably where productivity software is heading anyway.
The Legal Strategy Behind the Clone
Thomas isn’t just copying Microsoft’s code and hoping nobody notices. He’s using what’s called a clean-room rebuild — relying on public file-format specifications and observing how the original applications behave, without touching Microsoft’s actual source code. It’s the same legal playbook Compaq used in the 1980s when it cloned IBM’s PC BIOS. That approach held up then. Thomas seems to be betting it holds up now.
Whether Microsoft sees it that way is unclear. No statement from the company appears in the public record on this.
Microsoft’s Pricing Is the Real Target
Microsoft charges $99.99 a year for its 365 Personal plan. The family version runs $129.99. Those numbers add up, and for users who just need to open a .docx file or build a basic spreadsheet, the value proposition gets murky fast. Thomas’s suite is free, open-source, and reads the same file formats. That’s a direct challenge to Microsoft’s subscription model — not a subtle one.
His previous project, ArtCraft, which cloned Adobe’s Creative Cloud suite, set the template for what he’s doing now. ArtCraft showed that AI-assisted development can reproduce complex, professional-grade software fast. The Office clones follow the same logic.
And the community collaboration angle matters too. Because the code is public, developers anywhere can jump in, fix bugs, add features, and push the apps further than Thomas could alone. That’s the open-source bet — that collective development outpaces what any single team can do behind closed doors.
Compatibility with real-world files is still the big outstanding question. Office documents in the wild are messy. They have embedded objects, complex formatting, macros, revision histories. How WordCraft and GridCraft handle that chaos at scale hasn’t been fully tested yet.
DeckCraft’s 93% basic functionality coverage is the headline number for now.
Frequently Asked Questions
What are WordCraft, GridCraft, and DeckCraft?
They’re open-source clones of Microsoft Word, Excel, and PowerPoint, built by developer Brandon Thomas using Anthropic’s Claude and released on GitHub under MIT and Apache 2.0 licenses.
How complete are the Microsoft Office clones right now?
WordCraft covers roughly 60% of Word’s features in alpha, GridCraft supports 513 Excel functions at about 50% readiness, and DeckCraft covers 79% of PowerPoint’s features with basic functionality at 93%.
