Free PDF Metadata Editor

1. What PDF metadata actually is

Every PDF file carries an invisible layer of context alongside its visible pages: the document information dictionary, a small set of key-value pairs that describe who made the file, what it is about, when, and in what language. This metadata is what file explorers display in their “Properties” pane, what search engines and academic indexes use to identify documents, and what email gateways and content-management systems read to classify attachments. Editing it is the difference between a file that announces itself as Q3 2026 Financial Report — Acme Corp and one that shows up everywhere as Document1.pdf.

2. The nine standard metadata fields

The PDF specification defines a standard set of entries in the information dictionary. This tool reads and writes all nine that pdf-lib exposes:

• Title — the document’s human-readable name. Shown in browser tabs, OS file previews, and search results.
• Author — the person or organisation that produced the document. Powers attribution in academic and corporate contexts.
• Subject — a short description or subtitle. Often used by cataloging tools to summarise the file’s purpose.
• Keywords — a comma-separated list of terms that describe the content. Stored as an array inside the PDF, used by indexing systems.
• Creator — the original authoring application (e.g. Microsoft Word, Adobe InDesign). Identifies which tool produced the source document.
• Producer — the PDF library that wrote the final file (e.g. pdf-lib 1.17.1, Adobe PDF Library 17.0). Identifies the conversion pipeline.
• Language — a BCP-47 language tag such as en-US or fr-FR. Helps screen readers pick the right pronunciation, search engines index by language, and CMS workflows route by locale.
• CreationDate — when the document was first created. Automotive for filing systems and retention rules; editable here to back-date or post-date for compliance.
• ModificationDate — when the document was last modified. Updated automatically by most readers when the file is touched, but editable here for full control.

3. Why editing metadata actually matters

Metadata is more than cosmetic. A lawyer filing a contract wants the recipient to see the matter name in their file explorer, not the internal filename. A researcher distributing a paper wants academic indexes to pick up the title, author, and language correctly. A marketing team sending a case study wants it to show up as Acme — Case Study, not draft_v17_FINAL.pdf. And in the opposite direction: metadata can leak identifying information — a Word export might reveal the author’s real name, an internal team name, or the source machine — which is why journalists, lawyers, and whistleblowers routinely strip metadata before publishing sensitive documents.

4. How this tool reads and writes metadata

The tool loads your PDF with pdf-lib and calls each getter (getTitle(), getAuthor(), getCreationDate(), …) to populate the form, then calls the matching setters when you click Apply & Downloadand re-serialises the document. Crucially, this operation touches only the information dictionary — page content streams, fonts, images, annotations, and form fields are untouched. The visual document is byte-for-byte identical; only the metadata layer changes. The page-1 preview in the live panel confirms that: it never moves no matter what you type into the form.

5. The live preview, and why it matters

Two things preview side by side. On the left, a rasterised thumbnail of page 1 so you can confirm you opened the right file — a real mistake given that all the action happens in the form, not on the page. On the right, a field-by-field preview of the metadata block as it will appear in the saved file, with the resolved date strings and the parsed keyword array. As you type, the preview updates in real time, so the file you download is exactly what the preview shows. No surprises, no last-mile translation.

6. Clearing fields, clearing traces

Empty string fields are written as cleared, not skipped — leave Title blank and the existing title entry is removed from the dictionary entirely. Clearing the date pickers sets them to the Unix epoch, which PDF readers treat as unset. Reset to original restores the values that were in the file when you uploaded it; for a full wipe, clear every field by hand. This is the simplest way to anonymise a document before sharing it — combine it with the page-level operations in the related Splitter or Page Delete tools if you also need to remove identifying page content.

7. Browsers, not servers

Uploading a draft contract, a medical record, or a confidential memo to a free online metadata editor is a real privacy risk: most such services store uploaded files for some period, and you have no audit trail over who accessed them. This tool runs the entire pipeline inside your browser tab using pdf-lib compiled to JavaScript and pdfjs-dist for the page preview. The file is loaded into your device’s memory, the metadata setters mutate the in-memory object, and the modified PDF is generated and downloaded directly back to your device. No upload step exists. Confidentiality is structural, not promised.

8. Limitations worth knowing

This tool edits the standard information dictionary only. It does not modify XMP metadata — the XML-based extension that Adobe introduced later and that some tools write in parallel. Most readers and indexes still fall back to the information dictionary when XMP is absent, so the standard fields remain the most widely-read metadata in practice. For documents where XMP correctness is critical (rare outside specialist publishing pipelines), a dedicated XMP editor is the better tool. For the vast majority of office, academic, and legal workflows, editing these nine fields is exactly what you need.