runlocally

Small tools that run locally in your browser.

Convert, build, read and trim files — entirely on your device. Free, open source, and nothing is ever uploaded.

🔒 No upload. Your files never leave your device.

Images

HEIC to JPG

Convert iPhone HEIC photos to JPG or PNG.

WebP to JPG

Convert WebP images to JPG or PNG.

Rename Images in Sequence

Reorder photos, then download them renamed in sequence as a .zip.

Images to XLSX

Build an Excel image index: thumbnail, file name, size, and info per row.

ZIP & archives

Create ZIP

Bundle your files into a single .zip archive.

ZIP Viewer

See what's inside a .zip without extracting it.

Fix ZIP Filenames

Repair garbled (mojibake) filenames in a .zip.

Unzip

Extract a .zip and download its files.

Encrypt ZIP

Create a password-protected (AES-256) .zip.

Unlock ZIP

Remove the password from a .zip you can open.

Recover ZIP

Salvage files from a broken or corrupted .zip.

Remove from ZIP

Delete selected files from a .zip.

Merge ZIP

Combine multiple .zip files into one.

Split ZIP

Split a large .zip into smaller parts.

Extract RAR/7z

Open RAR, 7z or TAR archives and download the files inside.

PDF

Split PDF

Extract page ranges into a new PDF.

Merge PDF

Combine several PDFs into one.

PDF to Image

Render PDF pages to PNG or JPG.

Extract PDF Text

Pull the text out of a PDF into a .txt file.

Audio & video

Remove Silence

Cut silent gaps out of an audio file.

Trim Audio

Cut an audio clip to a start and end point.

Data

CSV Viewer

Open and read CSV files right in your browser.

Hex Viewer

Inspect any file as a hex dump, right in your browser.

XLSX to CSV

Split an Excel workbook into one CSV per sheet, zipped.

Excel Workbook Viewer

Open and browse an Excel workbook: switch sheets, no editing.

XLS to XLSX Converter

Convert a legacy Excel 97-2003 .xls file to modern .xlsx.

XLSX to Markdown Table

Turn a worksheet into a Markdown table you can copy or download.

XLSX to JSON

Convert an Excel sheet into JSON or JSONL.

Compare Excel Workbooks

Compare two Excel workbooks cell by cell, sheet by sheet.

CSV to XLSX

Combine multiple CSV files into one Excel workbook, one sheet per file.

Merge Excel Workbooks

Merge every worksheet from multiple Excel workbooks into one.

Documents

EML Viewer

Open a saved .eml email and read it in your browser.

Winmail Viewer

Open a winmail.dat and download the real attachments.

Markdown Viewer

Open a local .md file and read it as sanitized, rendered HTML.

Edit Markdown Table

Edit a table in a grid — the Markdown syntax stays perfectly aligned.

Extract Images from Excel

Collect images embedded in an .xlsx/.xlsm workbook and download them as a ZIP.

Strip XLSX Metadata

Remove author, company, and custom-property metadata from an Excel workbook.

Remove Excel Sheet Protection

Remove sheet and workbook editing protection from an XLSX/XLSM file you can already open.

Utilities

Draw Flowchart

Write flowchart syntax, see it rendered live. Export as SVG or PNG.

Edit Flowchart

Edit a Mermaid flowchart visually — structure only, code stays lossless.

Strip Tracking Params

Remove UTM/fbclid/gclid and other tracking params from a URL.

Format JSON

Pretty-print, validate, or minify JSON.

Compare Text

Diff two texts, line by line.

Edit ASCII Diagram

Edit a Unicode box-drawing diagram — CJK and emoji widths stay correctly aligned.

Identify File Type

Detect a file's real type from its binary signature, not its extension.

HAR Viewer

Inspect a .har network capture — requests, timing waterfall, headers — with warnings for exposed tokens.

Decode Certificate

Decode X.509 certificates and CSRs — no server ever sees the private material.

Format SQL

Pretty-print SQL queries across MySQL, PostgreSQL and more dialects.

Convert Color

Convert live between HEX, RGB and HSL with a preview swatch.

Convert Timestamp

Convert between Unix timestamps and human-readable dates.

Encode Base64

Encode or decode Base64, for text or binary files, byte-for-byte.

File Hash

Compute SHA-256, SHA-1 or MD5 for a file and compare against an expected value.

Password Generator

Generate cryptographically random passwords with guaranteed character-class coverage.

QR Code Generator

Turn text or a URL into a static QR code — no redirect or tracking layer.

Decode JWT

Inspect a JWT's header, payload, signature, and time claims in your browser.

Convert Case

Convert names between camelCase, snake_case, kebab-case and more.

Count Text

Count characters, words, lines and bytes in pasted text.

Inspect Characters

See each character's Unicode code point and UTF-8/UTF-16 bytes.

Spell Characters

Read out letters and digits with clear phonetic code tables.

Normalize Text

Apply Unicode normalization and Japanese width conversion with a diff preview.

YAML to JSON

Convert YAML files or pasted YAML to JSON entirely in your browser.

Why "run locally"?

Privacy here is structural, not a promise — there is no server to upload to.

✓Nothing is uploaded. Files are read and processed in your browser.
✓Works offline. Each tool is a PWA you can install and use without a network.
✓Open source (MIT). The code is public — you can read exactly what runs.
✓No accounts, no tracking pixels. Just the tool and your files.