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Langzapp is a professional offline document translation application for Windows. It translates DOCX, PDF, PPTX, XLSX, SRT, VTT, and plain text files using AI models that run entirely on your computer. No internet connection is needed during translation — your documents never leave your PC.
Internet is required only during installation, to download language models from Gumroad and activate your license key. Once activated, Langzapp runs completely offline — no ongoing internet connection is needed. All translation processing happens entirely on your PC. Your documents are never sent to any server.
Langzapp uses state-of-the-art open-source AI models (OPUS-MT, Qwen, LFM2, IndicTrans2) that produce excellent results for professional and technical content. Translation output is best treated as a high-quality first draft for a human reviewer to refine. It is not intended as a replacement for certified human translation in legal or medical contexts.
Langzapp is available in six plans, priced as a one-time payment for a perpetual license — no subscription, no recurring fees:
Every paid plan is backed by a 14-day money-back guarantee, plus your first year of updates and email support.
Paid plans don't offer a free trial — as a one-time, perpetual-license purchase, they're not eligible for trial pricing. Every purchase is backed by a 14-day money-back guarantee, so you can buy with confidence. If you'd like to try the software first with no commitment at all, Langzapp Lite is free, forever, covering English, German, French, and Spanish.
Every license includes all document format support (DOCX, PDF, PPTX, XLSX, SRT, VTT, TXT), all languages in your chosen plan, a perpetual right to use that version of the software, and a 14-day money-back guarantee. Your first year also includes free updates and email support.
No. Langzapp is a one-time purchase for a perpetual license — once activated, it keeps working indefinitely, with no renewal required. Your first year includes free updates and email support; after that, your installed version continues to work at no additional cost.
Since it's a one-time purchase, there's nothing to cancel — but we offer a 14-day money-back guarantee if you're not satisfied. Contact us within 14 days of purchase for a full refund, no questions asked.
No. There's no renewal and no recurring charge of any kind. If we release paid updates after your first year, they'll be entirely optional.
Your license key is in your Gumroad purchase confirmation email. It's also visible in your Gumroad account under Purchases. It's a unique alphanumeric code — keep it safe, as it activates your perpetual license.
On first launch, Langzapp asks for your license key. When you enter it, the application sends the key to the Gumroad license verification API, which confirms the key is valid and records one use against it. Your plan allows one use, meaning the same key cannot be activated on another device. After successful activation, Langzapp works fully offline — no internet needed for translation.
Each license key permits activation on one PC only, enforced by Gumroad's use-count system. If you need Langzapp on a second PC at the same time, you'll need a second license. If you've replaced your PC and need to move your license to the new machine, contact us at support@langzapp.com and we'll reset your activation.
Langzapp verifies your license key once, during activation. Because it's a perpetual license rather than a subscription, there's no ongoing monthly check — once activated, the application works fully offline indefinitely. No documents, personal data, or machine information is ever transmitted.
Check that: (1) you have an internet connection during first launch, (2) you're entering the key exactly as it appears in your Gumroad email — no extra spaces. If the key shows as already used and you haven't activated on another machine, contact us at support@langzapp.com with your Gumroad order number and we'll resolve it promptly.
Email us at support@langzapp.com with your Gumroad order number. We'll reset your use count so you can activate on your new machine. We handle transfer requests promptly, usually within 1 business day.
After purchasing, your installer is available in two places: (1) the Gumroad receipt email sent to you at purchase — click "View Content" or "Download" inside that email, or (2) your Gumroad Library — log in, go to the Library tab, find Langzapp, and click Download. Full step-by-step instructions are on the Download page.
Yes, Langzapp is completely safe. The SmartScreen warning appears because we are a new publisher and Windows has not yet seen enough installs to establish full trust automatically. Click "More info" then "Run anyway" to proceed. The installer is code-signed and scanned clean.
Language models for your chosen plan are downloaded automatically from Gumroad during the installation process — there is no separate step. Models are stored in %APPDATA%\Langzapp\models\ and remain there permanently. You will only need to re-download models if you install a new version of Langzapp.
Microsoft Word must be installed on your PC for DOCX translation — Langzapp uses the Word COM API to preserve formatting accurately. For all other formats (PDF, PPTX, XLSX, SRT, TXT) Word is not required.
Each model is typically 200–500 MB (INT8-quantised). A full European pack is approximately 2–3 GB. Asian language models (Chinese, Japanese, Korean) are larger at around 1–2 GB each. IndicTrans2 models for Indian languages are similar in size. You only download the languages in your plan.
Langzapp supports: DOCX (Word), PDF, PPTX (PowerPoint), XLSX (Excel), SRT and VTT (subtitles), and plain text / Markdown files.
Yes. For DOCX, formatting (fonts, styles, tables, headers) is preserved via the Word COM API. For PPTX, slide layouts are kept intact. For PDF, translated text is overlaid on the original layout. Excel formulas are never touched — only text cells are translated.
Yes. For language pairs without a direct model (e.g. German → French, or Hindi → Tamil), Langzapp uses pivot-through-English routing: German → English → French. This maintains good quality while keeping the model library manageable.
A typical 10-page DOCX translates in under 1 minute on a modern CPU. Large PDFs (50+ pages) may take 3–5 minutes. Langzapp shows real-time progress throughout.
Langzapp Indic Core and Langzapp Indic Pro are plans designed specifically for Indian language translation, powered by IndicTrans2 — the most accurate neural translation model available for all 22 scheduled Indian languages.
Indic Core (₹900 one-time) — English plus all 22 scheduled Indian languages: Assamese, Bengali, Bodo, Dogri, Gujarati, Hindi, Kannada, Kashmiri, Konkani, Maithili, Malayalam, Manipuri, Marathi, Nepali, Odia, Punjabi, Sanskrit, Santali, Sindhi, Tamil, and Telugu.
Indic Pro (₹1,900 one-time) — everything in Indic Core plus 9 international languages: German, French, Spanish, Italian, Portuguese, Chinese, Japanese, and Russian. Ideal for professionals working across Indian and global markets.
Yes — Langzapp Indic Core (₹900 one-time) and Langzapp Indic Pro (₹1,900 one-time) are priced in Indian Rupees and billed through Gumroad, which supports INR payments. EUA PRO A, EUA PRO B, and Asia PRO are priced in US Dollars at $19 one-time.
Yes — both Langzapp Indic Core and Langzapp Indic Pro are covered by the same 14-day money-back guarantee as all other paid Langzapp plans.
Yes. IndicTrans2 supports direct translation between Indian language pairs (e.g. Hindi → Tamil, Bengali → Telugu) without routing through English. This is one of the key advantages of IndicTrans2 over general-purpose models.
Each plan is a separate license with its own key and installation. If you need both Indian and European languages, you would need Langzapp Indic Pro (which includes German, French, Spanish, Italian, Portuguese, Chinese, Japanese, and Russian) or separate installations. Contact us if you need a custom bundle.
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