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Browse all pages and tools available on PDFCheck. Everything you need for PDF analysis and optimization.
PDF Tools
Free PDF analysis and optimization tools
- PDF Metadata Checker Check PDF metadata, creation dates, and author information
- PDF Validator Check that a PDF parses and review structure and metadata warnings
- AI PDF Indicator Check Check generator metadata for signs of AI or automated PDF tools
- AI PDF Chat Chat with any PDF using source-backed AI answers and page citations
- PDF Optimizer Compress and optimize PDF file size
- PDF Signature Checker Find digital signatures and read signer and certificate details
- PDF Image Extractor Extract all images from PDF documents
- PDF Accessibility Checker Check five basic accessibility signals, including tags and language
- PDF/A Validator Screen a PDF for PDF/A declarations and common archival issues
- Batch PDF Checker Analyze multiple PDF files in one verification workflow
- PDF Text Extractor Extract searchable text from PDF documents
- PDF to Markdown Convert PDF content into structured Markdown
- PDF Font Checker Identify fonts and embedding details in PDF files
- Compare PDFs Compare PDF versions and identify document changes
- Merge PDF Combine multiple PDF files into a single document
- Split PDF Split a PDF into individual pages or custom page ranges
- PDF to Image Convert PDF pages to PNG or JPG images
- PDF Password Add or remove password protection from PDF files
- PDF Metadata Editor Edit PDF title, author, subject, keywords, and creator fields
- PDF Metadata Remover Remove hidden PDF metadata for privacy before sharing documents
- PDF Form Filler Fill in interactive PDF form fields online
- PDF Form Builder Add fillable form fields to any PDF document
- PDF Editor Add text, shapes, and annotations to PDF pages online
- PDF Highlighter Highlight PDF text, add notes, and download annotated PDFs online
- All PDF Tools Complete archive of PDFCheck analysis, editing, conversion, and automation tools
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Learn about our PDF analysis methods
Developers
API documentation and developer resources
- API Documentation REST API reference and code examples
- MCP Server Model Context Protocol server for AI integrations
- AI Agents Guide Use PDFCheck through MCP, APIs, and agent workflows
- Chrome Extension Browser extension for quick PDF analysis
- LLMs.txt AI/LLM integration information
- LLMs Full Complete LLM context documentation
Blog
PDF tips, security guides, and best practices
- All Articles Browse all editorially reviewed blog articles
- How to Make a PDF Fillable Add text fields, checkboxes, dropdowns and radio groups to an existing PDF in your browser, name them so the data is usable, avoid the radio-group trap near the page bottom, and test the form before sending it.
- How to Check When a PDF Was Created, and How Far to Trust the Date Find a PDF's creation date, decode the raw D: string, see what a real report makes of two dates, and learn which ordinary events make the date misleading.
- How to Check a PDF Version (1.4, 1.7 or 2.0) and What It Means Read a PDF's version in a report, a viewer or the terminal, learn why two tools can disagree, and fix a version a portal refuses without faking the header.
- How to Convert PDF Pages to Images Without Blurry Text PNG or JPG, 72 to 600 DPI: measured pixel sizes and file sizes from our test pages, the settings the converter applies, and what a page image can no longer do.
- Why Is My PDF Signature Invalid or Unknown? A Troubleshooting Ladder Invalid usually means the signed bytes changed. Unknown usually means your reader can't trust the certificate. Work down five rungs, with a measured byte-range example, to find which one you have and what to do about it.
- How to Edit PDF Metadata: Title, Author and More Change a PDF's title, author, subject, keywords or creator on a copy. See a measured before-and-after of what the rebuild keeps, what it drops, and when to edit the source document instead.
- How to Check a PDF in Chrome Before You Trust It Read a PDF in Chrome's viewer, open its Document properties, understand what Safe Browsing does and does not cover, and know when to run a deeper check.
- How to Highlight a PDF Online, and What Happens to the File Highlight passages in a PDF from your browser, keep the original intact, and understand why drawn highlights behave differently from the comment highlights in Acrobat or Preview.
- How to Fix PDF/A Validation Errors Match each PDF/A error to its cause, fix it in the source document, re-export with the PDF/A option, and validate the new file. Includes three test files I ran through our checker.
- How to Check a PDF Before You Send It: a Pre-Send Checklist Eight checks on the exact file you are about to send: recipient rules, every page, searchable text, structure, fonts, hidden metadata, signatures and size, with what each tool can and cannot tell you.
- How to Fill Out a PDF Form Online Find out whether your PDF has real fields, fill them in the browser, decide about flattening, and learn from a measured test fill why totals stay empty and some letters refuse to save.
- How to Identify Fonts in a PDF Before Editing or Printing Read the font list stored in a PDF, decode names such as COMMLB+Helvetica, tell embedded, subset and referenced fonts apart, and see what one page looks like exported two ways.
- How to Fix an “Invalid PDF” Error When Uploading A troubleshooting ladder for files a portal rejects: not really a PDF, cut off, password-protected, too big, or breaking an unpublished rule. With the exact messages our checker gives for each.
- How to Create an Accessible PDF from Microsoft Word Build the structure in Word, export with tags switched on, then check the file. Includes the five signals our checker reads, how three test files scored, and what no checker can see.
- How to Search a Scanned PDF When Ctrl+F Finds Nothing Why search fails on a scanned PDF, three quick tests that prove the pages are images, and how to get searchable text with OCR, including what our converter can and cannot read.
- PDF to Markdown for AI Work: What You Actually Get, Line for Line I converted a two-page inspection report to Markdown and pasted the result here. See what survives, what turns into plain lines, when OCR takes over, and how to check the text before it goes into a prompt.
- How to extract images from a PDF online, and why you get more files than you expected Pull the photos, logos and scans out of a PDF at their stored size. What a measured 3-page test returned, which file types land in the ZIP, and the cases where converting the page is the better move.
- Password Protect a PDF Online: a Secure Sharing Checklist Add an open password to a PDF, pick one that will hold, test the file and send the password by a different route. Plus exactly what 128-bit RC4 protection does and does not do.
- Batch PDF verification: how to check many PDFs at once Upload a set of PDFs, read the columns the batch checker gives you, and learn which differences are worth opening the full report for and which questions a metadata batch cannot answer.
- Split and Merge PDF Pages Online: What Carries Over and What Doesn't Split a PDF into single pages, merge up to 20 files in any order, and rebuild a document page by page. With measured results for what gets lost, why split pages can be huge, and which errors to expect.
- How to Compress a PDF Without Losing Quality (and When You Can't) Measured results for four compression levels on photo, text and scanned PDFs, why a text-only file can come out larger, and what to check before you replace the original.
- What an Online PDF Accessibility Checker Can Tell You, and What It Can't A five-signal check finds missing tags, title, language, text and bookmarks in seconds. Here is how each signal is counted, three files I measured, and why a 5/5 score is not WCAG or PDF/UA.
- How to chat with a PDF using AI, and how to check what it tells you What happens between your question and the answer in PDF AI Chat: how pages become excerpts, how eight of them are picked by word matching, what a page citation proves, and which answers need you to open the page.
- How to Compare Two PDF Files: Wording, Appearance or Properties Pick the comparison that answers your question, see what a property comparison of an original and a converted copy really shows, and learn when a match is not identity.
- How to Remove Metadata From a PDF Before Sharing Blank a PDF's Title, Author, Subject, Keywords, Creator and Producer before sharing, see exactly what a cleaned test file still contained, and learn why this is not redaction.
- How to check if a PDF has been edited: five signs and what each one proves A PDF keeps no log of its edits, so you read the signs: dates, the software that last wrote the file, the hash, the signed byte range, and a copy from the source. Measured examples show what each sign looks like and where it stops.
- How to View PDF Metadata Online and on Your Own Computer Where a PDF keeps its title, author, software and dates, how to read them online or with Acrobat Reader, Chrome, Preview and pdfinfo, and how to decode a raw PDF date string.
- Can you detect an AI-generated PDF? What the file actually records A PDF names the software that built it, not who wrote the words. See how the AI-generator score adds up from Creator and Producer, measured scores for ten common producers, and why a 0 or a 95 proves nothing about authorship.
- How to Verify a PDF Digital Signature, and What a Checker Cannot Tell You Verify a signed PDF in three steps: confirm nothing changed since signing, confirm the certificate is trusted, confirm where the time came from. With a real byte-range example from our test file.
- Why PDF Metadata Matters: What It Reveals, and What It Can Never Prove Viewers, search tools and recipients read your PDF's properties without opening a page. Here is where they show up, a test file read back field by field, what leaks, and why none of it proves who wrote the document or when.
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