345 free online tools
Find a tool by task, format, or name. Check its example and limits before working with PDFs, images, text, or data in your browser.
Explore tools
CSS filter generator
Combine CSS image filters with live before/after previews, then copy the generated rule.
Watermark PDF
Center a diagonal text watermark on every PDF page and inspect the actual output page by page.
PDF metadata workspace
Inspect and edit PDF metadata, resolve XMP conflicts, or clear supported fields locally.
Resize PDF pages
Fit each visible PDF page onto A4 or US Letter with chosen orientation and margins.
N-up PDF
Create a printable PDF with two or four source pages per sheet and preview every output sheet.
Grayscale image
Make a grayscale-looking PNG from one color image and compare it with the original.
Watermark image
Add a custom text label inside the lower-right edge of one image and compare the exported PNG.
Image border and padding
Add an equal-width solid outer border to one image without cropping its picture.
Stitch images
Arrange two or more images in one vertical or horizontal PNG without resizing them.
Image contact sheet
Create a PNG grid of 2–20 image thumbnails with optional numbered filenames.
CSV comparison by key
Compare two small CSV exports by a unique key and inspect added, removed and changed cells.
CSV lookup and join
Join two small CSV tables by selected key columns. Preview matches and choose left, inner or full output.
CSV pivot table
Group records into a cross-tab and calculate sums, counts, means, minima or maxima for each group.
Split CSV by column
Separate one CSV into files for each distinct group and download a manifest mapping group values to output filenames.
JSON structural comparison
Compare JSON values structurally and locate changes with JSON Pointer paths, without losing large integer precision.
JSON Merge Patch
Apply an RFC 7396 merge patch locally: update object fields, delete fields with null and replace arrays as whole values.
JSON Patch workspace
Apply RFC 6902 JSON Patch operations in order, review array index shifts and download the complete result.
NDJSON validation and quarantine
Validate pasted or imported NDJSON line by line; download valid records and a report with every rejected original line.
HAR request analysis
Analyze a local HAR export, list every failed request and summarize status classes and slow requests without contacting recorded URLs.
robots.txt rule tester
Test pasted or imported robots.txt rules for one URL and crawler token, with an allow decision, selected group, winning rule and line number.
Sitemap XML audit
Audit a pasted or imported Sitemap XML file for namespace, schemaLocation pairs, URL structure, duplicates, host consistency and common optional fields.
Nginx exact redirect rules generator
Convert a source,target CSV into exact-path Nginx location and return rules, checking duplicate sources and same-site loops.
CSP policy inspection
Inspect a pasted CSP policy for malformed source expressions, duplicate directives, broad allowances and missing restrictions.
Inspect and verify JWT
Inspect complete JWT header and claims, or verify HS256 / RS256 with a separately supplied trusted key.