JustPDF vs Prompt Builder
Side-by-side comparison to help you choose the right AI tool.
Privacy-first PDF toolkit with 17 free tools.
Prompt Builder
Generate, optimize, test, and manage AI prompts in one place. Turn an idea into a ready-to-use prompt in seconds.
Visual Comparison
JustPDF
Prompt Builder
Overview
About JustPDF
JustPDF provides 17 professional-grade PDF tools that process files entirely in the user's browser. Unlike Smallpdf, iLovePDF, and other online PDF tools that upload files to remote servers, JustPDF uses JavaScript and WebAssembly to handle everything locally on the device. Files never leave the browser — verifiable by checking the Network tab in DevTools. Tools include: Merge PDF, Split PDF, Compress PDF, Rotate PDF, Flatten PDF, Unlock PDF, PDF to Word, Word to PDF, PDF to JPG, JPG to PDF, PDF to Excel, WebP to PDF, HEIC to PDF, PDF to Grayscale, Sign PDF, Chat with PDF (AI), and OCR/Scan. No account needed for the free tier (3 ops/day). Pro starts at $4/month for unlimited access. FERPA-compliant for educational use.
About Prompt Builder
Prompt Builder is a prompt engineering workspace for writing, testing, and saving prompts. Describe the task in plain English, and it helps you create a prompt that matches the model you choose. Start with a draft, refine it in chat, save or pin versions, then run them when you are ready. It works with GPT, Claude, Gemini, Llama, Mistral, DeepSeek, Grok, Perplexity, and more. You also get an Optimizer, an assistant for quick tests, and a library of reusable prompts and templates from the community. Turn an idea into a ready-to-use prompt in seconds. Refine it in chat, save it to your Library, and run it anytime.