FusionPDF Blog
Guides for PDF, developer, and QR tools — all running privately in your browser.
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Developer
Image Converter Online Free — JPG, PNG, WebP, AVIF, GIF, BMP
Convert between any image format in your browser using the Canvas API — no upload. When to use JPG vs PNG vs WebP vs AVIF, quality slider explained, and browser support for next-gen formats in 2026.
Developer
Cron Expression Parser Online Free — Validate & Explain Any Cron Job
Paste any cron expression and see the next 5 run times in plain English. Full 5-field and 6-field (Quartz/AWS EventBridge) reference, cross-system syntax differences, timezone pitfalls, and debugging guide.
PDF Tools
PDF to Long Image Free — Convert PDF to One Scrollable PNG
Stitch all PDF pages into one tall PNG for sharing on Twitter/X, LinkedIn, or Notion. DPI options (72/150/300), canvas size limits, and tips for WhatsApp sharing explained.
Developer
Text Case Converter Online Free — UPPERCASE, lowercase, Title Case & More
Convert text to camelCase, PascalCase, snake_case, kebab-case, SCREAMING_SNAKE_CASE and more. Developer naming conventions, AP vs Chicago Title Case rules, and database column to label conversion guide.
Developer
HTML Entities Encoder & Decoder Online Free — Escape Special Characters
Encode < > & and 20 other common entities to prevent XSS. Named vs numeric entity formats, OWASP XSS prevention, encoding vs sanitizing — and when JSON needs entity encoding.
How-To
HEIC to JPG Online Free — Convert iPhone Photos Without iTunes
Convert Apple HEIC photos to JPG in your browser using WebAssembly — no upload, no iTunes. Why Windows can't open HEIC files, EXIF/GPS metadata handling, batch conversion, and quality trade-offs explained.
PDF Tools
How to Print a PDF as a Booklet Free — Saddle-Stitch Layout in Minutes
Automatic page imposition for saddle-stitch booklets — the tool reorders your pages so they print correctly folded. Paper size guide, printer duplex settings, and what to do when page count isn't a multiple of 4.
QR Codes
QR Code Scanner Online Free — Scan with Camera or Upload an Image
Decode any QR code in your browser — live camera scan or upload a screenshot. How ZXing-js reads the pixel matrix, what QR codes can contain (WiFi, vCard, URL, SMS), and why local scanning matters for privacy.
Developer
Slug Generator Online Free — Convert Any Title to a URL-Safe Slug
Instantly convert titles to SEO-friendly URL slugs. Why hyphens beat underscores (confirmed by Google's John Mueller), accented character handling, CMS-specific slug rules, and what happens when you change a slug.
Developer
Binary, Hex, Octal & Decimal Converter Online Free
Convert between binary, octal, decimal, and hexadecimal instantly. Manual conversion methods, 0-15 reference table, two's complement for negative numbers, bitwise operators, and the 0b/0x/0o prefix guide.
Developer
Unix Timestamp Converter Online Free — Epoch Time to Human Date
Convert Unix timestamps to readable dates in local and UTC time. Seconds vs milliseconds (the 10 vs 13 digit gotcha), the Year 2038 problem, useful epoch values table, and code snippets for JS/Python/SQL.
Developer
Color Converter Online Free — HEX, RGB, HSL, CMYK Instantly
Convert any color between HEX, RGB, HSL, and CMYK in one click. Screen vs print gamut explained, out-of-gamut color warning, modern CSS oklch() context, and when to use each format for web vs print design.
Developer
Markdown Preview Online Free — See Your Markdown Rendered Instantly
Live Markdown preview in your browser — CommonMark and GFM (tables, task lists, strikethrough). Full syntax cheatsheet, export as HTML, and comparison with Dillinger, StackEdit, and VS Code preview.
PDF Tools
N-Up PDF Online Free — Put 2, 4, or 6 Pages Per Sheet
Combine multiple PDF pages onto one printed sheet — 2-up side by side, 4-up grid, or 6-up. How pdf-lib handles scaling and placement, printer settings after N-up (always print at 100%), and paper size guide.
Developer
Text Diff Checker Online Free — Compare Two Texts Instantly
Highlight additions and deletions between any two texts in your browser. How the Myers diff algorithm works, side-by-side vs inline mode, and why it's safer than upload-based diff tools.
PDF Tools
How to Remove Annotations from a PDF Free (Comments, Highlights & Markup)
Strip highlights, comments, sticky notes, and markup from any PDF in seconds. Difference between removing and flattening annotations — and when each is the right choice.
Developer
UUID Generator Online Free — v1, v4, v5 Explained
Generate UUIDs in your browser using crypto.getRandomValues(). UUID v1 vs v4 vs v5, collision probability math, and when to use UUID vs ULID vs NanoID for database primary keys.
PDF Tools
How to Add a Header or Footer to a PDF Free Online
Add custom text, page numbers, dates, or company names to headers and footers — left, center, or right. Dynamic variables like {page} and {totalPages} supported.
PDF Tools
How to Convert PDF to PDF/A Free Online (Archival Format)
PDF/A is the ISO 19005 long-term archival standard required by courts, government agencies, and compliance teams. PDF/A-1b vs PDF/A-2b vs PDF/A-3b — which variant you actually need.
PDF Tools
How to Duplicate PDF Pages Free (Online, No Software)
Clone any page or set of pages within a PDF — useful for templates, exam forms, certificates, and booklet preparation. How pdf-lib clones pages without re-encoding.
PDF Tools
How to Insert a Blank Page into a PDF Free (Online Tool)
Add a blank divider page at the beginning, end, or between any pages of a PDF. Common uses: section breaks, cover pages, annotation space for printed documents.
PDF Tools
How to Remove Images from a PDF Free (Online, No Install)
Strip embedded images from a PDF to shrink file size by up to 60% and create a clean text-only version. Explains the difference between removing images and removing watermarks.
PDF Tools
How to Convert a PDF to Grayscale Free Online (Black & White)
Color printing costs 3–4× more than black and white. Convert any PDF to grayscale in-browser using the W3C luminosity formula — lossless quality, 30–60% smaller file for image-heavy PDFs.
PDF Tools
Scan Document to PDF Free — Use Your Phone Camera or Webcam
Turn paper into a PDF using your phone camera or laptop webcam — no app install. Uses the MediaDevices.getUserMedia() API; camera stream never leaves your device.
Developer
URL Encoder & Decoder Online Free — RFC 3986 Reference
Encode special characters for safe URL transmission and decode percent-encoded strings from logs or redirect chains. encodeURI vs encodeURIComponent — the critical difference with code examples.
PDF Tools
PDF Reader Online Free — Open Any PDF in Your Browser (No Install)
Open, navigate, zoom, and read any PDF in Chrome, Firefox, or Safari — no software install. Rendered locally by PDF.js; your file never touches a server. Mobile and desktop.
PDF Tools
How to Extract Images from a PDF Free (No Upload, No Software)
Pull every embedded image from a PDF and download them as individual PNG or JPG files — in your browser. Why client-side extraction is safer for documents with sensitive photos.
PDF Tools
How to Reverse PDF Page Order Free — Flip Any PDF Instantly
Reverse the page order of any PDF in seconds — handy for scanner output that comes out last-page-first. How pdf-lib reverses the page array without re-encoding content.
PDF Tools
How to Interleave PDF Pages Free — Merge Two PDFs in Alternating Order
Combine two PDFs by alternating pages: A1, B1, A2, B2… Perfect for duplex scan assembly — scan odd pages, scan even pages reversed, then interleave into one complete document.
Developer
Lorem Ipsum Generator Online Free — Paragraphs, Words & Bytes
Generate placeholder text in paragraphs, words, or exact byte counts instantly. The history of lorem ipsum, why Cicero's "de Finibus" was the source, and when NOT to use Latin placeholder text.
Developer
Word Counter Online Free — Count Words, Characters & Reading Time
Instant word, character, sentence, and paragraph count with estimated reading time. Covers how word counts differ across tools, and why character limits matter for SEO meta tags and Twitter.
Developer
CSV to JSON Converter Online Free — Paste, Convert, Copy
Convert CSV to JSON in one click — handles quoted fields, commas inside values, and custom delimiters. When to use array-of-objects vs array-of-arrays, with JavaScript and Python code examples.
Developer
How to Format and Validate JSON Online — Free, No Upload
Pretty-print, minify, and validate JSON in your browser. Spot syntax errors with line numbers — and why a client-side formatter is safer for sensitive API data.
Developer
How to Decode a JWT Token — Free Online Decoder (No Upload)
Decode any JWT to inspect its header and payload. Why decoding isn't verifying, what each claim means, and why a browser-based decoder never exposes your production tokens.
Developer
Base64 Encoding Explained — Encode and Decode Free Online
How Base64 turns binary into text, when to use it (data URIs, email, embedding), and the critical warning: Base64 is encoding, not encryption.
Developer
MD5 vs SHA-256: Which Hashing Algorithm Should You Use? (2026)
MD5 is fast but broken for security; SHA-256 is the modern standard. When to use each, how collision attacks work, and why neither alone is right for passwords.
Developer
How to Create a Strong Password — Free Generator and 2026 Guide
Length beats complexity. How password entropy works, crack-time tables by length, passphrases vs random strings, and how a client-side generator keeps passwords private.
Developer
How to Test Regular Expressions Online — Free Regex Tester
Test regex with live highlighting. Common patterns (email, URL, phone), flags, capture groups, greedy vs lazy, and how to avoid catastrophic backtracking.
QR Codes
How QR Codes Work + How to Create One Free (No App, No Signup)
How QR codes encode data, what error correction levels do, static vs dynamic (and why static means no tracking), plus how to create one free in 3 steps.
QR Codes
How to Create a WiFi QR Code Free — Share WiFi Without Typing the Password
Let guests connect to WiFi by scanning a code — no password typing. The WIFI: string format, how phones auto-connect, the security caveat, and how to make one free.
How-To
How to Edit a PDF for Free — No Adobe Acrobat, No Upload
8 common editing tasks mapped to free tools. Honest: FusionPDF can't replace existing text inline — but covers signing, watermarking, page numbers, redacting, and more.
How-To
How to Compress a PDF to Send by Email (Free, No Upload)
Gmail: 25 MB. Outlook: 20 MB. Practical guide to compressing PDFs under attachment limits — including the grayscale trick for maximum reduction.
Tool Comparisons
Best PDF24 Alternative — Browser-Based, No Download Required
PDF24 Online uploads to German servers. PDF24 Desktop is local but requires installation. FusionPDF is browser-only on any device. Honest comparison of all three.
How-To
Convert HEIC Photos to PDF Free — iPhone Photos to PDF, No Upload
Two-step workflow: HEIC to JPG, then JPG to PDF. Combine multiple iPhone photos into one PDF. HEIC files contain GPS metadata — here's why no-upload matters for phone photos.
PDF Tools
How to Add a Watermark to a PDF for Free (No Upload)
Add diagonal text or image watermarks to every page locally — no upload, no account. Covers opacity, angle, font size, and when watermarking actually protects your document.
PDF Tools
Free Online PDF OCR — Make Scanned PDFs Searchable (No Upload)
Tesseract.js runs optical character recognition in your browser — no upload, no server. Supports 100+ languages and achieves over 95% accuracy on clean scans at 300 DPI.
PDF Security
How to Password Protect a PDF for Free — No Upload Required
AES-256 encryption applied entirely in your browser using PDF-lib. Set an open password, an owner password, or both — and understand exactly what each protects against.
How-To
How to Convert PDF to Word Free — Extract Editable Text (No Upload)
FusionPDF extracts all text from PDFs as .txt — the privacy-safe alternative to upload-based converters. Honest guide on what works and what doesn't.
Tool Comparisons
Best Smallpdf Alternative — 49 Free PDF Tools, No Upload Required
Side-by-side comparison of Smallpdf vs FusionPDF on privacy, pricing, file size limits, and number of tools. With a guide on which to use when.
Tool Comparisons
Best Free Adobe Acrobat Alternative — No Subscription, No Upload
Adobe Acrobat Pro costs $239.88/year. FusionPDF covers the most common tasks for free. Honest breakdown of what FusionPDF replaces — and what it doesn't.
How-To
How to Rotate Specific PDF Pages for Free (No Upload, No Software)
Fix one sideways page in a scanned document without re-encoding anything. Lossless rotation explained — with the technical reason why some viewers still show it wrong.
Tool Comparisons
iLovePDF vs FusionPDF: Which Is Safer for Confidential Documents?
iLovePDF uploads files to EU servers and deletes them in 2 hours. FusionPDF never uploads. Here's when the difference matters — and how to verify either tool yourself.
How-To Guides
How to Compress a PDF Without Losing Quality (Free, No Upload)
Light mode is lossless. Aggressive re-encodes images. Here's how to pick the right compression level — and why it matters which tool you use for confidential files.
How-To Guides
How to Merge PDF Files for Free — No Upload, No Signup
Lossless quality, no watermark, no file size cap. Plus: when to use Split or Interleave instead — and why upload matters when assembling confidential documents.
How-To Guides
Split PDF Free — Extract Pages Without Uploading
Gmail caps at 25 MB. Base64 adds 33% in transit. Here's how to extract pages without sending your whole document to any server — and the syntax for page ranges.
How-To Guides
How to Convert Word to PDF Free: No Upload, No Microsoft Office
The FBI warned in 2025 that fake file converter sites deploy ransomware. FusionPDF uses mammoth.js and jsPDF to convert DOCX locally — nothing sent to any server.
How-To Guides
How to Remove PDF Password Free — Unlock Any PDF in Your Browser
Owner-locked PDFs can be unlocked client-side with PDF.js — no software, no upload. Here's when it works, when it doesn't, and why browser-based unlocking is safer than any upload tool.
How-To Guides
How to Rotate PDF Pages Free — No Upload, No Software (2026)
Rotate one page or every page — 90°, 180°, or 270°. Changes are applied in-browser using PDF-lib; the file never leaves your device and quality is lossless.
How-To Guides
How to Add Page Numbers to a PDF Free (No Upload, No Acrobat)
Pick position, font, size, and starting number. PDF-lib renders the numbers directly into the PDF stream — no rasterization, no quality loss, no upload.
How-To Guides
How to Convert Excel to PDF Free — No Upload, No Microsoft 365
SheetJS parses your XLSX locally and outputs a clean, printable PDF. No $9.99/month subscription, no upload — and formulas stay as values so there's nothing to leak.
How-To Guides
How to Compress a PDF to 1 MB Free (No Upload)
Gmail caps at 25 MB and many portals require under 2 MB. Here's the exact workflow — Light, Aggressive, or split-compress-merge — to hit a target size without losing readability.
How-To Guides
How to Convert JPG to PDF Free — Combine Images, No Upload (2026)
Combine multiple JPG, PNG, or WEBP images into one PDF — drag to reorder, choose A4 or Letter, adjust margins. Everything runs client-side; works on mobile too.
How-To Guides
How to Extract Text from a PDF Free — Copy or Download as TXT
Extract selectable text or run OCR on scanned documents with Tesseract.js. Copy directly or download a .txt file — no upload, and OCR accuracy exceeds 95% on clean scans.
How-To Guides
How to Convert PDF to JPG Free — No Upload, Adjustable DPI (2026)
PDF.js renders every page to a canvas element and exports JPG or PNG at your chosen DPI — 72 for web, 150 for email, 300 for print. Download all pages as a ZIP.
Privacy & Security
How to Redact a PDF Free — Permanently Black Out Text, No Upload
Highlight-and-delete is not redaction. Here's how to permanently remove sensitive content — flattened, unrecoverable — without uploading your document to any server.
How-To
How to Delete Pages from a PDF Free
Remove specific pages from any PDF directly in your browser. Select by page number, range, or thumbnail. No upload — your document stays private.
How-To
How to Rearrange PDF Pages Free
Rearrange PDF pages with drag-and-drop thumbnails. Fix mis-scanned documents, reorganize reports, move cover pages — all without uploading a file.
How-To
How to Add Text to a PDF Free
Add text labels, captions, and annotations to PDF pages using a browser-based overlay tool. No upload, no Acrobat license required.
How-To
How to Crop PDF Pages Free
Remove unwanted margins, borders, and whitespace from PDF pages. Important: cropping adjusts the visible area — the underlying content is preserved.
PDF Tools
How to Repair a Corrupted PDF File Free
FusionPDF attempts to recover the PDF structure using PDF.js + pdf-lib. Covers what corruption types can and cannot be repaired — honest guide.
PDF Security
How to Remove PDF Metadata Free
Strip author name, creation date, GPS data from embedded images, software info, and revision history before sharing confidential documents.
How-To
HTML to PDF Free — Convert Web Pages Online
Convert HTML files or web page source to PDF in your browser. Covers limitations honestly: complex JavaScript and some CSS may not render as expected.
Tool Comparisons
Best Free PDF Tools in 2026
Objective comparison of FusionPDF, PDF24, iLovePDF, Smallpdf, and Adobe Acrobat. Which tool wins on privacy, pricing, features, and real-world usability?
PDF Tools
How to Flatten PDF Forms Free
Convert interactive PDF form fields into permanent, static content. Essential before sharing completed forms, signing documents, or archiving.
How-To
How to Resize PDF Pages Free
Change PDF page dimensions to A4, Letter, A3, Legal, or custom sizes. Covers scale-to-fit vs exact dimensions and when resize vs compress is the right tool.
PDF Security
How to Change a PDF Password Free
Update an existing PDF password or remove encryption entirely. Covers open password vs owner password, AES-256, and what FusionPDF cannot do (brute-force).
How-To Guides
How to Sign a PDF Free Online — No Printing, No Signup (2026)
Draw, type, or upload your signature and place it on any PDF page. The signature is flattened into the PDF locally — no upload, no account, no printing required.
71 free tools — all in your browser
PDF, developer, and QR tools. Merge, compress, format JSON, generate QR codes. Free, no signup, no upload.