Guides
Walkthroughs that use several tools in turn to solve a whole problem, grouped by the area they start in.
Accessibility
Writing content everyone can readMake text, captions and charts that work for more people: plain-language reading levels, why fancy Unicode letters break screen readers, invisible characters, caption timing, and colours that survive colour blindness.
Is my web page accessible?Check a page for the problems that shut people out: automatic checks, text contrast, colour blindness and keyboard focus order, with what to fix first.
Audio
Making an audiobook from recorded chaptersTurn a chapter-by-chapter recording into one M4B audiobook: trim each chapter, match their loudness, add a cover, join them with a chapter list, and check the result.
Practising music: tuning, tempo and slowing it downTune your instrument, find a song's tempo and practise to a metronome, play a drone or reference note, and slow a hard passage down so you can learn it by ear.
Making a private podcast feed of your own recordingsListen to your own recordings, notes or articles read aloud in your podcast app: trim and level each episode, check its tags, put the files on your web space and write the RSS feed that apps follow.
Getting a sound clip ready to useTurn a raw recording into a clip for a podcast, course or video: cut it to length, fade it, check for hum, set its loudness to the target the platform uses, and remove the details it carries.
Ciphers
Making a puzzle, treasure hunt or escape roomBuild clues that have one answer: check anagrams and word clues, encode messages as pigpen, flags, Morse or Enigma, make a two-transparency reveal, and playtest it before anyone sees it.
Solving an unknown cipherFrom a page of gibberish to plain text: find what kind of cipher it is, read its letter statistics, then crack it or decrypt it with a key.
Data
Making barcodes and QR codes, and fixing a rejected numberFind the typo in an IBAN, ISBN or card number a form rejects, make barcodes and QR codes that scan, test them before printing, and see where a QR code leads before you open it.
From a messy CSV to clean dataCheck a CSV for broken rows, fix its encoding, look through it as a table, convert it to JSON, split or join large files and chart the result.
Opening a Parquet, SQLite or Excel data exportLook inside a data file you can't open: read a Parquet file's columns and rows, browse an SQLite database or an Excel workbook, query any of them with SQL, and save the answer as CSV or a chart.
Making test data for a demo or test systemFill a demo, test system or import with realistic made-up data instead of real people's: describe the rows, link tables by ID, choose CSV, JSON or SQL, check it before loading, and add test files.
Developer
Documenting a project's files, tables and linksWrite a README or handover note that's easy to follow: draw the folder structure as a tree, turn a spreadsheet into a table, make every link the same format, give files tidy names and check the Markdown.
Debugging a failing API callFrom a browser's network capture to a fix: find the failing request, read its status, token and times, turn it into code, and share the capture safely.
Why won't my JSON file load?Find the error in a JSON file that a program rejects, repair the common slips, check it has what the program expects with a JSON Schema, and find your way round a large file.
Handling passwords and tokens in your own appStore passwords as bcrypt hashes and choose the cost, make API keys and store only their hash, add two-factor sign-in with TOTP, and check the tokens your app issues.
Reading a crash or a logFind the cause of an error: filter a log by level and time, find your code in a stack trace, read timestamps and compare a working config.
Testing an upload limit or a slow uploadFind out whether an upload problem is the file size, the number of files or the connection: make test files of exact sizes, work out how long they should take, capture what the browser did, and match it to the server's log.
What is this file?Work out what an unknown file really is, look inside its bytes, check it against a published hash, and unpack compressed or encoded data.
What time is this number? Timestamps in logs and IDsWork out which kind of time a number is (Unix, Windows, Chrome, .NET, Excel, GPS and more), read the time hidden in an ID, find the bytes in a file, and turn a day or week into exact start and end times.
Why is Git ignoring my file (or not ignoring it)?Find out why Git ignores a file you want to commit, or keeps showing one you meant to ignore: test your .gitignore patterns, re-include a file inside an ignored folder, stop tracking a committed file, and spot invisible characters.
Documents
Filling in, signing and returning a formFill in a PDF form, put your signature on it, check what the file gives away, protect it with a password if it holds private details, and send it back.
Paper and templates for printing or an e-ink tabletMake lined, graph, dot grid, Cornell or music paper to print or load onto an e-ink tablet, mix different kinds into one notebook PDF, print it as a folded booklet, and convert a template to another format.
Putting a PDF together to sendTurn photos and scans into one PDF, add and reorder pages, get it under an upload limit, clean it before it goes, and take pictures, pages and text out of a PDF you've been sent.
Publishing an ebook that stores acceptFrom a manuscript to an EPUB that Apple Books, Kobo and Kindle accept: write it in Markdown, make the book with a cover and pictures, check it for the errors stores reject, and size the cover and pictures.
Sending an invoiceWork out the due date, make an invoice as a PDF, sign it if the client wants a signature, and protect it with a password when it goes by email.
E-learning
Loading learning data into SuccessFactors with connectorsGet users, courses or learning history into SuccessFactors Learning by connector without rejected rows: convert spreadsheet rows, fix the encoding, check every field, split large files and read the connector log.
Why won't my course work in the LMS?Fix an e-learning package an LMS rejects or won't track: check the ZIP, play it in a test LMS, decode suspend data, and check xAPI statements and captions.
Is this email genuine?Check a suspicious email: read it safely, trace where it came from, see whether it passed SPF, DKIM and DMARC, and look at its links and attachments.
Moving contacts between contact appsMove your contacts from one app or service to another, such as Outlook, Google Contacts, Apple Contacts or a CRM: export them, merge and tidy the files, fix garbled names, and save them in the format the new app imports.
Encoding
Decoding Base64, URL and other encoded text, and escaping itWork out what a strange string in a log, link or config is and decode it, layer by layer; then escape text correctly for JSON, a shell command, a URL, HTML or a regular expression so it arrives as you meant.
What's inside this JWT?Read a JSON Web Token's claims, see when it was issued and when it expires, check its signature, and look at the certificate behind its key.
Everyday
Arranging a meeting across time zonesFind an hour that suits everyone, share it when you don't use the same calendar system, avoid the weeks the clocks change on different dates, and work out why an invitation shows the wrong time.
Planning a photo shoot or a night of stargazingPick the place and the day, then the hour: golden hour and twilight for photographs, the darkest hours and a moonless night for the stars, for a town or a spot on a map.
Keeping a workshop day on timeRun a workshop or training day that starts and restarts on time: send times that suit remote attendees, put a link to the materials on screen, keep the screen awake, and show a break countdown everyone can see.
Fonts
Why does my document look different on their computer?Fonts that weren't embedded, fonts that weren't allowed to be, and fonts the other computer doesn't have: find which fonts a PDF uses, check a font's embedding rights, and choose fonts that survive the trip.
Getting a font ready for the webCheck a font's licence and features, convert it to a web font with its @font-face CSS, stop the page jumping when it loads, and set a type scale.
Images
Before you share a photo or documentFind and remove what a file gives away: the location in a photo or video, tags in a recording, faces and numbers on a screenshot, and the names and history inside PDFs and Office files.
Finding what's hidden in a pictureLook for messages hidden in an image's metadata, pixels or bit planes, behind zero-width characters, and in the spectrogram of a sound file.
Getting images ready for a websiteSize and compress photos for the web, choose between JPEG, PNG, WebP and SVG, export logos at the sizes you need, take a colour scheme from a logo, and make the share image and icons.
Screenshots for a blog post, slide or app storeCheck a screenshot's size, frame it, mark it with a watermark, combine several into one image, compare versions and make the files small enough to publish.
Mac
Checking a downloaded Mac app before you open itBefore opening an app from the web: check the download matches the checksum its maker publishes, see what's in the ZIP, who signed the app and their team ID, whether it runs natively on Apple silicon, and what it's allowed to do.
Customising your Mac: icons, shortcuts, links and scheduled jobsGive an app or folder your own icon, add a keyboard shortcut to any menu command, make link files for the Dock and desktop, and run a script on a schedule with launchd.
Checking Mac profiles, plists and .DS_Store filesCheck a configuration profile before installing it, read a plist to see what an app or background job is set to do, and see what a .DS_Store gives away.
Maps
Solving a geocache puzzleFrom a mystery cache listing to the final coordinates: decode the clues, work out the formula, convert the position and check the distance and bearing.
Sharing a walk or ride route safelyShare a GPS track without giving away where you live: check its distance and climb, hide the start and end, remove times, convert it for another app, put your photos on the route and give a meeting point in any format.
Security
Getting an HTTPS certificate: from request to installedMake a certificate signing request with the right names, check what the certificate authority sends back, confirm the certificate matches your private key, put the chain in the right order, and check the site's security headers afterwards.
Sending a file only the right person can openLock a file with a password before you email or upload it, choose a password that holds up, send the password a different way, and check the file arrived unchanged.
Setting up an SSH key for GitHub or a serverMake an SSH key pair, add a passphrase, put the public key on GitHub or a server, fix the 'permissions are too open' error, choose the key for each host, and check which key is which by its fingerprint.
Strong passwords, two-factor codes and shared secretsStrong passwords and passphrases, two-factor codes and secrets split between people, all made and checked in your browser.
Text
Cleaning up text copied from a PDF, email or web pageClean up text copied from a PDF, an email or a web page: rejoin broken lines, fix quotes and spaces, change case, sort and de-duplicate a list, compare two lists, and turn rows into a Markdown table or clean HTML.
Filtering a log or file: Line Filter or Log Viewer?Choose between the Line Filter and the Log Viewer to cut a log or text file down to the lines you need, and use them together when one isn't enough.
Fixing garbled textTurn café back into café: spot text read in the wrong encoding, see the characters behind it, repair it and remove invisible characters that break things.
Video
Before a video call or recordingCheck your camera and microphone, see how loud your room is, and try a short screen recording before an important call, interview or recorded talk.
Recording a how-to videoRecord your screen with narration, trim the start and end without losing quality, take a thumbnail, make a short GIF for documentation, shrink it to fit an email, and check the captions before you share it.
Making a short animated GIF for docs or a chatRecord a few seconds of your screen or take a clip from a video, turn it into an animated GIF small enough to post, fix its timing and frames, and know when a short video is the better choice.
Getting a still frame and the recording details from a videoFind when and where a video was recorded, step to the exact frame you need, save stills and a contact sheet, and compare frames for what changed.
Web
Fixing sitemap errorsFind out why a search engine rejects or ignores your sitemap.xml: check it's well-formed XML, find bad addresses and dates, keep within the size limits, and make sure robots.txt lets crawlers reach it and the pages it lists.
Moving a website without losing visitorsRebuild or move a site without broken links: map every old address to its new one, turn the map into redirect rules for your server or host, avoid chains and loops, and check robots.txt, status codes, share previews and structured data on the new site.
Making a page look finished with CSSPick colours that match a logo and are readable, set a type scale, then build the gradient, shadow, shaped edge, blob and animation curve that make a plain page look finished.
Getting a website ready to launchThe finishing touches before a site goes live: favicons, share cards, structured data for search results, robots.txt and the sitemap, security headers and SRI hashes, and a check of its HTTPS certificate.
A website works for me but not for one userWhen a page works for you but not for someone else: find out their browser and settings, see what they see, capture the requests their browser makes, and check their keyboard, without a call or remote access.