Tools that run inside your browser
Every tool on this site does its work inside your browser tab. Your documents and photos are opened by your own device and are never sent to a server — not to us, not to anyone.
164tools
0uploads
100%work offline
These need an internet connection: your browser asks a public service directly (a DNS resolver, a certificate database…). Nothing is sent to our server, and each page says which service it uses.
PDF14
- Compress a PDFTwo ways: a lossless tidy-up that keeps the text, or page rasterising that shrinks scans by 70–90%. Runs locally, no upload.
- Merge PDF filesCombine several PDFs into one, in your browser. No upload, no sign-up, no watermark, no page limit.
- Split a PDFSplit a PDF by page ranges, into single pages, or every N pages. Runs in your browser: no upload, no sign-up.
- Reorder, rotate and delete PDF pagesDrag page thumbnails to reorder, rotate or delete pages, then save the PDF. Entirely in your browser.
- Scan documents with your cameraPoint your phone at a document: the page edges are detected, the perspective is corrected and multiple pages export as one PDF. The camera feed never leaves the device.
- Compare two PDF documentsRender both PDFs and highlight every pixel that moved, alongside a word-level text diff. Nothing is uploaded.
- Convert a PDF into imagesRender each page as PNG, JPG or WebP at the resolution you choose, and download them as a ZIP. Nothing is uploaded.
- Make a PDF from imagesStack photos or scans into a single multi-page PDF, on A4, Letter or a page that follows each image. Nothing is uploaded.
- Watermark a PDFStamp text, a logo or page numbers across every page of one or many PDFs. Opacity, position and size are yours to set. Nothing is uploaded.
- Extract the images inside a PDFPull every embedded photo and graphic out of a PDF at its original resolution, preview them, and download as PNG or a ZIP. Nothing is uploaded.
- Put a password on a PDF — or remove oneTwo functions in one tool: lock PDFs with real AES-256 encryption, choosing whether printing and copying stay allowed — or remove the password from PDFs whose password you know. Everything runs inside your browser; nothing is uploaded.
- Pull a table out of a PDFFind tables in a PDF whose text can be selected, preview the grid, and download it as CSV (for Excel) or copy it as Markdown. What it cannot detect is listed too. Runs in your browser.
- Look inside a PDFBrowse every object in a PDF — pages, streams, fonts, metadata, encryption — with search, type filters and a saved-generations check. A developer’s X-ray, run locally.
- Redact a PDF or image, for realDraw boxes over sensitive regions; the pages are rebuilt as flat images with the boxes burned in, so no text survives underneath. Locally.
Image21
- Convert HEIC to JPGTurn iPhone HEIC/HEIF photos into JPG or PNG without uploading them. Batch conversion, quality control, EXIF kept or stripped.
- Convert images between formatsConvert JPG, PNG, WebP, AVIF, GIF, BMP, SVG and HEIC in batches. Resize, rotate and compress in the same pass. Nothing is uploaded.
- Convert images to PNGTurn JPG, WebP, AVIF, HEIC, GIF, BMP or SVG into PNG, in batches, inside your browser. No quality loss, no upload.
- Convert images to WebPBatch-convert JPG, PNG, HEIC and more to WebP in your browser. Typically 25–35% smaller than JPG at the same quality.
- Convert images to AVIFConvert JPG, PNG, WebP and HEIC to AVIF on your own device, in your browser. AVIF is the smallest of the common web image formats.
- Convert SVG to PNGTurn SVG files into PNG images at whatever size you need, in your browser. Batch conversion, transparency preserved.
- Resize imagesResize photos by longest side or to exact dimensions, in batches, shrinking in steps so the result stays smooth. Nothing is uploaded.
- Rotate and flip imagesRotate by 90, 180 or 270 degrees and flip horizontally or vertically, in batches, without uploading anything.
- Convert images to greyscaleTurn colour photos into greyscale in batches, weighting the colours the way the eye sees brightness rather than just averaging them.
- Compress imagesMake JPG and PNG files smaller with the MozJPEG and OxiPNG compressors, running in your browser. Batch, no upload, real before/after sizes.
- Make a photo collageArrange photos in a grid and export a single PNG, JPG or A4 PDF. Drag to reorder, set columns, gaps and corners. No upload.
- Remove the background from a photoCuts out the main subject of a photo with an AI model that runs in your browser. The photo is never uploaded. The model is downloaded once and kept for next time.
- Resize an image with AIEnlarge a small photo with an AI model that runs on your own device (up to 2048 px wide), or shrink one cleanly. No upload, no account, no watermark.
- Make a colour transparent by clickingClick the background and everything of that colour disappears. Keep clicking on the leftovers. Exports a transparent PNG, nothing uploaded.
- Crop images to a proportionCut photos to a square, 16:9, 4:3, A4 or any common proportion, in batches, choosing which part to keep. Nothing is uploaded.
- Adjust images in batchesBrightness, contrast, saturation, sharpening, sepia and greyscale applied to a whole folder at once. Nothing is uploaded.
- Get the dominant colours of an imagePull the main colours out of a photo or a logo, with the share of the image each one covers. Copy as CSS variables or JSON.
- Frame imagesPut a border, an inner mat, rounded corners and a drop shadow on photos — the same frame applied to a whole folder at once. Nothing is uploaded.
- See your design as colour-blind readers see itSimulate protanopia, deuteranopia, tritanopia and more on any image or PDF page, compare side by side, and export the views. Local.
- Build a timeline from your photosDrop hundreds of photos: a day-by-day timeline with thumbnails, camera and lens statistics, a per-month chart and a coordinates plot — plus a self-contained HTML report. Local.
- Count things in a photoPhotograph a pile of similar objects and get them counted. Two modes: instant detection for round things seen end-on — pipes, rebar, logs, bottles, pills — or an AI mode where you box 1–3 examples and a local model counts anything. Correct with a tap, download the numbered image. The photo never leaves your device.
Video & audio12
- Extract frames from a videoTake still images out of a video, either one every so many seconds or a fixed number in total, and download them as a ZIP. Runs in your browser with FFmpeg (a video tool) — nothing is uploaded.
- Turn audio into a waveform imageDraw the waveform (the picture of a sound’s ups and downs) of an MP3, WAV or M4A file and save it as PNG or SVG. Bars or a line, your own colours, transparent background. Nothing is uploaded.
- A focus soundscape with rules, not just slidersMix rain, wind, fireplace, stream, white/pink/brown noise and a low rumble — all synthesised in your browser — with rules: fade in, bring the rumble in later, go quiet on pomodoro breaks, end the session on time. Nothing downloaded or streamed.
- Convert videoConvert between MP4, WebM and MKV with FFmpeg compiled to WebAssembly. Resolution, frame rate and quality controls. Nothing is uploaded.
- Compress a videoReduce a video’s size with FFmpeg running locally: lower the resolution, the frame rate or the quality, and see the real before and after.
- Trim a videoCut a clip out of a longer video by start and end time, locally, without re-uploading gigabytes anywhere.
- Extract the audio from a videoPull the soundtrack out of any video as MP3, M4A, WAV, OGG or FLAC, locally, with no upload and no length limit beyond your device.
- Turn a video into a GIFMake a clean animated GIF from a video clip with a per-clip colour palette. Runs locally with FFmpeg — no upload, no watermark.
- Convert audio filesConvert between MP3, WAV, M4A, OGG and FLAC locally with FFmpeg. No upload, no length limit beyond your device.
- Speed a video up or slow it downPlay a video or audio file at 0.5×–2× speed. Keep voices natural with pitch correction, or let the pitch shift like a tape. Nothing is uploaded.
- Fade a video in and outAdd a fade from black at the start and to black at the end — audio fades along. Set each duration separately. Nothing is uploaded.
- Change a video’s audio trackStrip the audio out of a video, or swap in a new soundtrack from an audio file. The video stream is copied untouched — fast and lossless.
Documents24
- Romaji, hiragana and katakana — all at onceType in any box and every other form updates live: romaji, full-width romaji, hiragana, full-width katakana, half-width katakana. Runs in your browser.
- Convert a Word file (DOCX) to HTMLTurn a Word document into clean HTML for a website, in your browser. Headings, lists, tables and images are kept; Word’s fonts and colours are not. Nothing is uploaded.
- Convert DOCX to MarkdownConvert Word documents to clean Markdown, including tables. Runs locally: the document is never uploaded.
- Convert Markdown to HTMLRender GitHub-flavoured Markdown to HTML with a live preview, in your browser. Tables, task lists and fenced code included.
- Convert HTML to MarkdownTurn HTML into clean Markdown with Turndown, tables included. Nothing is uploaded.
- Convert a document to PDFTurn DOCX, Markdown or HTML into a PDF using your browser’s own print engine. No upload, no watermark, no page limit.
- Count words and charactersLive counts of characters, words, kanji, kana, lines and 400-character manuscript sheets, plus kanji-density readability. Nothing is uploaded.
- Compare two texts or documentsSide-by-side or inline diff of text, Markdown, HTML and DOCX, by line, word, sentence or character. Export a unified diff.
- Extract text from images and PDFs (OCR)Recognise Japanese (horizontal and vertical), English and more with Tesseract running locally. Exports plain text or a searchable PDF.
- Convert Japanese era datesConvert between 令和・平成・昭和・大正・明治 and Western dates, and count working days excluding Japanese public holidays.
- Convert an ePub to Markdown or HTMLTurn an ePub without copy protection (DRM) into clean Markdown text or a single HTML file with the pictures included, chapters in reading order. Nothing is uploaded.
- Make an invoiceFill in your details and line items, get a clean A4 invoice with totals and tax, and save it as PDF from the print dialog. Nothing is uploaded.
- Make a quotationLine items, totals and tax on a clean A4 quotation with a validity date, saved as PDF from the print dialog. Nothing is uploaded.
- Make a CV (Japanese rirekisho format)The standard Japanese rirekisho layout — photo, history table, licences, motivation — filled in the browser and saved as PDF. Nothing is uploaded.
- KyuukeiChan – active-break reminders for WindowsFree Windows program: every 30 min of real activity, an overlay with KyuukeiChan, a bodyweight exercise and a vocabulary word (JLPT, HSK, EN/DE/FR/IT/PT). No sign-up, nothing sent anywhere.
- Make a Japanese seal (hanko) and stamp documentsCreate round name seals (認印), square company seals (角印) and date stamps (日付印), then place them on a PDF or image with an inked look. Nothing is uploaded.
- Check the kanji level of a textPaste Japanese text and see every kanji coloured by JLPT level or school grade, with a breakdown table. Runs locally.
- Turn Markdown into slidesWrite Markdown, split slides with ---, download a single HTML file with keyboard navigation, speaker notes, a timer and print-to-PDF. No account, no internet to present.
- Add furigana to Japanese textAdds readings over every kanji using kuromoji + IPADIC — the dictionary family behind Japanese IMEs. HTML <ruby>, bracketed text or kana-only output. The 17 MB dictionary loads once from this site.
- Make a clean signature and sign a PDFDraw your signature or clean up a photo of one, get a transparent PNG/SVG, and place it on a PDF or image. Nothing leaves your browser.
- Turn your handwriting into a fontDraw each character in a box — kana, letters, digits — and download a real TrueType/WOFF2 font of your own handwriting. Built entirely in your browser.
- Show people how to say your nameMake a card with your name, its reading (kana), Latin spelling and a “say it like this” respelling — plus a recording of your own voice — as PNG, WAV or a self-contained HTML you can share. Nothing is uploaded.
- Japanese qualified invoice generatorCreate a 適格請求書 (Japan invoice-system qualified invoice) with the registration number checked, per-rate tax totals and a clean printable PDF. Nothing leaves your browser.
- Add or remove VATType an amount, pick the rate — 10% and 8% for Japan, 20%, 19%, 21% or any custom figure — and get net, tax and gross in either direction, with the rounding under your control. Works offline.
Data18
- Convert CSV to JSONTurn CSV or TSV into a JSON array of objects, with a preview. Quoted fields and embedded newlines handled properly.
- Convert JSON to CSVTurn a JSON array into CSV or Excel, with a BOM option so Excel on Windows opens Japanese correctly.
- Convert Excel to CSV or JSONRead .xlsx and legacy .xls in your browser and export CSV, TSV or JSON. Shift-JIS files decode correctly.
- Convert CSV to ExcelTurn a CSV or JSON file into a real .xlsx workbook locally, with no encoding surprises.
- Format JSONPretty-print and validate JSON locally. Your code is never uploaded — which matters when it contains keys, hostnames or customer data.
- Format XMLPretty-print and validate XML locally. Your code is never uploaded — which matters when it contains keys, hostnames or customer data.
- Format YAMLPretty-print and validate YAML locally. Your code is never uploaded — which matters when it contains keys, hostnames or customer data.
- Format SQLPretty-print and validate SQL locally. Your code is never uploaded — which matters when it contains keys, hostnames or customer data.
- Format CSSPretty-print and validate CSS locally. Your code is never uploaded — which matters when it contains keys, hostnames or customer data.
- Format HTMLPretty-print and validate HTML locally. Your code is never uploaded — which matters when it contains keys, hostnames or customer data.
- Build a Markdown tableEdit a table in a grid and get aligned Markdown instantly. Import CSV, TSV or an existing Markdown table.
- Compare two JSON, YAML or XML filesShows what really changed between two versions of a JSON, YAML or XML file. Key order, indentation and quote style do not count as changes. You get a list of the changed places and a side-by-side view.
- Test a regular expressionType a regular expression (a search pattern) and see the matches highlighted as you type, plus a table of the captured parts and a live find-and-replace preview. JavaScript rules; runs in your browser.
- Generate realistic, made-up test dataChoose columns — Japanese names, addresses, phones, emails, prices, dates, UUIDs (long random IDs) — set the number of rows and download CSV or JSON. All invented, all made in your browser.
- Filter a log fileDrop a log file, filter it by plain text or by a regular expression (search pattern), see the matching lines as you type, turn captured parts into table columns, and download the result. Runs in your browser.
- Compare two files byte by byteA heatmap shows where two files differ; click any region to open a synchronised hex view with the differing bytes highlighted. Any file type, local.
- Explain a number with things people knowTurn any length, area, volume, weight, time or headcount into everyday comparisons — Tokyo Domes, laps of the Yamanote line, elephants, blue whales — with sources. Copy the sentence or download a card.
- Postal code → address, in kanji, kana and romajiType a Japanese postal code and get the prefecture, city and town in kanji, katakana and romaji; look up a list at once, search by place name, and copy the address in Japanese or international format. All 124,000 entries load into your browser once and then work offline — nothing is looked up online.
QR codes19
- Bulk QR codes & barcodes from a spreadsheetTurn a column of a spreadsheet into thousands of QR codes or barcodes, downloaded as a ZIP or a printable label sheet. No upload.
- QR code for a websiteTurn any address into a QR code. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- Wi-Fi QR codeLet guests join your network by pointing a camera at a card. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- vCard QR code for contact detailsPut your whole contact card into one code. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- WhatsApp QR codeStart a WhatsApp chat with you, with the first message already written. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- LINE QR codeLet people add you on LINE by scanning. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- Email QR codeOpen a new email addressed to you, with subject and body ready. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- SMS QR codeOpen a text message to your number, already written. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- Phone number QR codeOffer to call your number when scanned. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- Calendar event QR codeAdd an event to the calendar with one scan. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- Location QR codeOpen a point on the map. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- Telegram QR codeOpen your Telegram profile or channel. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- Messenger QR codeOpen a Messenger conversation with your page. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- YouTube QR codeOpen a video or a channel. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- Zoom meeting QR codeJoin a meeting by scanning. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- Plain text QR codeEncode any text, with no link and no app behind it. Generated locally: nothing is uploaded, the code never expires and no one counts your scans.
- Generate barcodesMake Code 128, Code 39, EAN-13, EAN-8, UPC, ITF-14 and MSI barcodes in batches. Download as PNG or SVG. Nothing is uploaded.
- Read QR codes and barcodesScan with the camera or drop a screenshot, photo or scan. Reads QR, Code 128, EAN, UPC, DataMatrix and more. Nothing is uploaded.
- Print labels from a listA CSV column becomes a print-ready PDF matched to standard A4 label sheets (65/44/24/12 per page), QR or Code 128 plus text, with a skip-used-labels option. Local.
Forensics2
- See what is hidden inside a file, and remove itDrop a photo, a video, an audio file or a document and see everything it carries: camera and device, dates, GPS location, the software that touched it and in what order, author and company. Then remove it, in your browser.
- Examine an imageError level analysis, histogram and noise, full metadata, C2PA Content Credentials and AI-generator markers — plus a self-contained HTML report with the file’s SHA-256. No verdict invented.
Web29
- Generate a favicon setOne image in, a complete icon set out: a real multi-size favicon.ico, PNGs from 16 to 512, a maskable icon, the manifest and the HTML.
- Generate CSS visuallyDrag sliders, watch the live preview, copy the CSS: linear/radial/conic gradients, box-shadows with presets, per-corner radii and fluid clamp() sizes.
- Manage this site’s storage in your browserLists everything tools.loreatec.jp keeps in your browser — offline caches, downloaded engines, AI models, IndexedDB, OPFS — with working delete buttons.
- Subset a font in your browserKeep only the characters your site actually uses and get a WOFF2 (and TTF) that is a fraction of the size, plus the @font-face line. hb-subset — the engine Google Fonts uses — compiled to run locally.
- Describe the mood, get a paletteType how the design should feel — calm, bold, luxurious, 和風 — and get a harmonious six-colour palette with WCAG-checked text pairs, as hex/HSL, CSS variables, JSON or SVG. Deterministic, local, no AI.
- Which country is this IP address from?Paste one IP address, a list, or a whole server log, and see the country of each address plus a count by country. The country table is downloaded once and searched inside your browser — no address is sent anywhere.
- Time zone converter and world clockAdd cities from around the world and drag a bar to see the same moment in each one at once — for scheduling a call across time zones. Daylight saving is handled automatically, and the clocks keep working with no connection.
- How many days between two dates?Pick two dates and get the exact number of days between them — plus the same span in weeks, in calendar years-months-days, and split into weekdays and weekends. A second box adds or subtracts days from a date. Works offline.
- Check a page’s on-page SEOTwenty checks on how well a page is set up for search engines: title and description width, headings, image alt text, canonical link, Open Graph, hreflang, structured data. All in your browser.
- Generate meta tagsWrite the title, description and social-share (Open Graph) tags for a page while watching a live preview of the Google result and the social card. Copy and paste the result into your page.
- Preview your search resultSee how a page title and description will look in Google search results, cut off at the same width as the real thing, on desktop and on a phone.
- Preview your social share cardBuild and preview the card that appears when a page’s link is shared on social media (Open Graph and Twitter/X tags). Your browser loads the image straight from the address you give; nothing passes through this site.
- Generate structured data (JSON-LD)Structured data is extra code that tells Google what a page is about. Build it for a company, local business, article, product, FAQ, breadcrumbs, event or site search, and check existing code.
- Build and test a robots.txtrobots.txt is the file that tells search engines and other bots which parts of a site they may visit. Build one, block AI crawlers separately from search engines, and test any URL against the rules.
- Generate an llms.txtllms.txt is a short text file, placed at /llms.txt, that describes your site to AI systems (language models). Build one here. It is a convention, not a standard, and this page says what it does not do.
- Generate an XML sitemapA sitemap is the list of pages you hand to search engines. Turn a list of URLs into a valid sitemap.xml with last-modified date, change frequency and priority. Also opens an existing sitemap for editing.
- Generate hreflang tagshreflang tags tell Google which language versions of a page belong together. Build a complete, mutually linked set as HTML link tags, HTTP headers or sitemap entries, with checks for the usual mistakes.
- Generate redirect rulesA redirect sends visitors from an old address to a new one. Turn a list of old → new URLs into rules for Apache (.htaccess), nginx or Netlify, and catch chains, loops and duplicates before they go live.
- Base64 encode and decodeBase64 is a way of writing any data as plain letters and digits. Encode or decode text here, or drop a file to get a data: URI you can paste into a web page. Handles Japanese correctly; nothing is uploaded.
- Encode and decode URLsSpaces, Japanese, & or ? are not allowed as-is in a web address and must be written as %-codes. Encode a whole URL or a single value, or decode either. Detects internationalised (punycode) domains.
- Generate a hashA hash is a short fingerprint of a file or text. Compute SHA-256, SHA-384, SHA-512, SHA-1 or MD5 in your browser and compare it with the one the download page lists, to check a file arrived intact.
- Generate UUIDs and passwordsGenerate unique IDs (UUID v4) in bulk and strong passwords with a strength readout in bits. Uses the browser’s secure random-number source, and nothing leaves your device.
- Decode a JWTA JWT (JSON Web Token) is a login token used by many web apps. Read what is inside one, see when it expires, and check an HS256 signature with your secret key — all inside your browser.
- Convert timestampsUnix time is the number of seconds computers count from 1970. Convert between it, milliseconds, ISO 8601, your local time, UTC and Japan Standard Time. Type in any field and the rest follow.
- Check colour contrastCheck whether text is readable against its background. Measures the contrast between two colours against the WCAG 2 accessibility levels (AA and AAA) for body text, large text and buttons or icons.
- Convert text caseConvert between sentence case, Title Case, camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE and dot.case.
- Generate URL slugsA slug is the readable part at the end of a web address, like /tokyo-photos. Turn titles into clean slugs: accents removed, punctuation dropped, and Japanese kana written in romaji instead of being deleted.
- Generate placeholder textGenerate filler text for design mockups: lorem ipsum, English filler or real Japanese sentences, by paragraphs, sentences or words, so your layout is tested with realistic line lengths.
- Check keyword densityCount how often each word appears in a page’s text or HTML, and what share of the text it makes up, with common words filtered out. Runs in your browser.
Email17
- Read a message’s headersPaste an email’s headers and see the route it took, server by server, with the delay at each step; what the receiving server decided about the sender (SPF, DKIM, DMARC); what the spam filters wrote; and the sender fields. Entirely offline — this page makes no network request at all.
- Read your DMARC reportsDrop the .xml, .xml.gz or .zip files from your DMARC mailbox and get a readable table: who sent mail as your domain, how many messages, whether SPF and DKIM passed, what the receiver did, and which sources fail. Several reports at once, CSV export, no upload.
- Check the HTML of your emailPaste your e-mail HTML and see what mail clients will do to it: unsupported elements, external stylesheets, missing alt text, tracking pixels, the 102 KB Gmail clipping limit, link problems, and a preview at 320, 375, 600 and 800 px with images blocked and dark mode. Nothing is uploaded.
- Make the plain-text version of an HTML emailTurn your HTML e-mail into a readable plain-text alternative: headings, lists, and links written as “text <url>”, wrapped at 78 characters. Paste, copy, done — in your browser, with no upload.
- Inline the CSS of an emailMove the rules from your <style> block into inline style attributes, in the right order of specificity, keeping media queries and pseudo-classes where they have to stay. Runs in your browser; the HTML is never uploaded.
- Test your subject line and preheaderSee exactly where your subject is cut off in Gmail, Outlook, iPhone Mail, Yahoo! Japan and docomo, with full-width Japanese counted properly, plus an inbox preview and the words filters weigh. Live, in your browser.
- Understand a bounced emailPaste a bounce (NDR) and get the recipient, the status code, the receiving server’s own diagnostic, and what it actually means — including Gmail, Microsoft and Yahoo messages and the Japanese carrier filters (docomo, au, SoftBank, ドメイン指定受信). Offline.
- Is this email a phishing attempt?Paste a suspicious message and see the signals explained one by one: mismatched Reply-To, lookalike and punycode domains, failed authentication, links that go somewhere other than they say, dangerous attachments, and manufactured urgency. No verdict, no upload, no link is ever opened.
- See what is tracking you inside an emailPaste a message and find its tracking pixels, remote images, click-tracking redirect links and campaign parameters. Nothing is loaded and no link is opened, so checking a message here never tells the sender you read it.
- Check and clean a list of email addressesPaste a list and get syntax validation (RFC 5322 and 6531), likely typos of common domains including Japanese carriers, disposable domains, role accounts, Gmail dot and +tag normalisation, and a deduplicated clean list. CSV export. The list never leaves your browser.
- Open a .eml fileRead a saved e-mail without a mail program: headers, MIME structure, the HTML rendered in a sandboxed frame with remote images blocked, the plain-text part, the raw source, and downloadable attachments. Print or save as PDF. Nothing is uploaded.
- Decode =?ISO-2022-JP?B?…?= and other MIME encodingsDecode e-mail headers written as RFC 2047 encoded words, in UTF-8, ISO-2022-JP, Shift_JIS or EUC-JP, and decode quoted-printable or base64 body parts. Also encodes a header value correctly folded. All in your browser.
- Build the List-Unsubscribe headers (one-click unsubscribe)Create the two hidden mail lines, List-Unsubscribe and List-Unsubscribe-Post, that let Gmail and Yahoo show an unsubscribe button. The rules they apply to bulk senders since 2024 are checked as you type. Built in your browser.
- Build an email signatureMake an email signature in Japanese or Western order. It uses only the simplest HTML, with no images and no web fonts, so it looks the same in Outlook and every other mail program. Copy it straight into your mail settings, or take the code. Built in your browser.
- Build a mailto: linkMake a click-to-email link that opens the visitor’s mail program with address, subject, body, cc and bcc already filled in. Japanese text and line breaks are converted correctly, which is what breaks when the link is written by hand. Preview and ready-made HTML.
- Hide (obfuscate) an email address on a web pageFour ways to put an email address on your website without leaving it readable to the robots that collect addresses for spam. Each comes with working code, a live demo, and a frank note on what it really protects against. Made in your browser.
- Check a logo SVG for BIMI (your logo next to your emails)BIMI is the system that shows your logo next to your emails in some inboxes, and it only accepts a strict SVG format (SVG Tiny P/S). This checks your logo file against each rule and previews it at inbox size. The file is never uploaded.
Local AI1
Security6
- Print the first 60 minutes before you need themFill in your contacts, platforms and backups; get a one-page A4 card with what to do in the first hour of a ransomware attack, an e-mail compromise, a lost device or a cloud outage. Generated in your browser — your contacts are never uploaded.
- Nobody keeps access after they leaveTick the platforms and assets your company uses and get an offboarding (or role-change) checklist ordered by timing and owner — accounts, tokens, shared passwords, devices, badges. Print, Markdown or CSV. Nothing is uploaded.
- Put a number on the slow computerEnter your headcount, hourly cost and the minutes lost to slow PCs, crashes, outages and IT waiting; get the yearly cost as a range, a breakdown, and the payback time of a fix. Every assumption is visible and editable. Local.
- Write the AI usage rules your company does not have yetClassify your tools into three tiers, tick the data that must never be entered, choose permitted uses and reporting rules — and get a complete policy document in English or Japanese, as Markdown or a printable page. Nothing is uploaded.
- Twenty-five questions, honest answers, a planAnswer 25 baseline security questions across devices, accounts, backups, people and network; get your gaps ordered by importance and a printable action plan. Aligned with IPA’s SME baseline and Cyber Essentials. Your answers never leave the browser.
- Check what WebRTC reveals about youSee whether your browser hands your local or IPv6 addresses to any website that asks through WebRTC, and whether the modern placeholder protection is on. The whole test runs offline: this page contacts no server, not even ours.
Field ops2
- You have 60 places to visit. Who goes where, on which day, in what order?Paste a list of Japanese addresses (branches, stores, customer sites) and get them split into working days: which sites are visited on the same day, the driving order inside each day, the approximate arrival time at each one, and the kilometres. Exports to CSV, KML/GeoJSON (Google My Maps, Google Earth) and a printable route sheet per day. Geocoding by the Geospatial Information Authority of Japan; everything else runs in your browser.
- Find the competent office for any Japanese municipalityPick a prefecture and municipality (or type its name) and see, in one screen, the tax office (税務署), pension office (年金事務所), Hello Work (公共職業安定所), Labour Standards Inspection Office (労働基準監督署), Legal Affairs Bureau for company registration (法務局) and immigration office (出入国在留管理局) that cover it — with address, phone and official link. Data compiled from the agencies’ official jurisdiction tables; works offline.
Online tools14
Every other tool on this site works with no connection at all. These few need one, because they ask a question over the network — usually a public service such as a DNS resolver or a certificate database, straight from your browser. Each page names exactly what it contacts and what is sent; the “what is my IP” tool, by design, asks our own server (which sees your address anyway), and none of them route your files or data anywhere to hide it.
- Everything DNS says about your domain’s security, in one tableOne query, one table: SPF, DMARC, DKIM (common selectors), MTA-STS, BIMI, CAA, DNSSEC and TLSA/DANE for a domain, plus a Cloudflare-vs-Google comparison to spot propagation. Read via public DNS-over-HTTPS from your browser; nothing goes through this site.
- See every certificate ever issued for your domainSearch the public Certificate Transparency logs (via crt.sh) for a domain and its subdomains: hostnames, issuing CAs, first seen, expiry, soon-to-expire and expired. Find forgotten subdomains and certificates you did not request. CSV export.
- Convert with today’s rate — and know which day it isConvert between JPY, USD, EUR, GBP, CNY, KRW and 20 other currencies with daily reference rates; the date of the rate is always shown, and the last rates are kept in your browser so it still works offline. No account, no tracking.
- Find the archived copy of a pageCheck whether a web address is archived on the Wayback Machine, open the latest capture or the one closest to a date you choose, and jump to the full calendar. For dead links, evidence and “what did it say back then”. Direct from your browser.
- Is this dependency alive, and what licence is it?Paste a list of npm packages, PyPI packages or GitHub repositories and get the latest version, its date, the licence and how long since the last release — with old ones flagged. Weekly downloads for npm, stars for GitHub. CSV export. Queries go from your browser to the public registries.
- What is my IP address?Shows your public IPv4 address and its country, from our own server — no third-party service involved. The country is worked out inside your browser, so your address is not sent anywhere to look it up. An optional button adds IPv6, the owner and reverse DNS. For support calls, allow-lists and VPN checks.
- Test your email: paste the source, get the verdictPaste a message’s source or drop a .eml file and get a rough 0–10 score, explained: sender checks (SPF, DKIM, DMARC), spam blocklists, delivery route and about sixty content rules. In your browser, nothing uploaded.
- Check an SPF record, or build oneSPF is the list of servers allowed to send mail for your domain. Read a domain’s record and everything it includes, count the lookups against the limit of ten, catch the classic mistakes, and test whether a given IP is allowed to send. Builder included.
- Check a DMARC record, or build oneDMARC tells receivers what to do with mail that fails the sender checks. Read a domain’s record with every part explained, catch the usual typos, and check that an outside report address is really allowed to receive your reports — the part most checkers skip. Generator included.
- Check an IP or domain against mail blocklistsA blocklist is a public list of addresses known to send spam. Check an IP or domain against fifteen of them, plus its reverse DNS name, straight from your browser. Lists that cannot be checked from a browser are named as such — never reported clean — with a link to their own page.
- SEO meta checkerPaste a URL and get a pass/warn/fail audit of its title, meta description, canonical, robots, hreflang pairs, Open Graph tags, headings and image alts. Analysis runs in your browser.
- Look up DNS recordsQuery A, AAAA, CNAME, MX, TXT, NS, SOA, CAA and SRV records over DNS-over-HTTPS, and compare two resolvers to spot propagation.
- Check your email DNS recordsLook up MX, SPF, DMARC and a DKIM selector for a domain and see what each one means for deliverability. Queried from your browser.
- Look up a domain registrationQuery registration data over RDAP: registrar, creation and expiry dates, status codes, name servers and DNSSEC. Straight from your browser.
Why build it this way?
The usual free file converter works by uploading your file to a server, processing it there and giving you a link. That means a stranger’s machine has held your contract, your passport scan or your holiday photos, and you have only a privacy policy as a guarantee. It also means queues, size caps, watermarks and a sign-up wall.
Browsers have been able to do this work themselves for years. The same software engines that desktop programs use — the PDF engine from Firefox, the image code from Chrome, ffmpeg for video — now run inside the browser, on your own machine, at close to full speed. So we simply left the server out.
What that buys you
- Nothing to leak. There is no upload, so there is no copy of your file anywhere else.
- No limits worth mentioning. The ceiling is your own device, not a pricing tier.
- It works on a plane. Load a tool once and it keeps working with the connection off. (The only exceptions are the few “online tools”, which ask a public service such as a DNS resolver — and say so on their page.)
- No account, no watermark, no “pro” version.
See how to verify all of this yourself in about thirty seconds →