Every developer has a folder of bookmarks for tiny tasks: format this JSON, encode that string, generate a QR code for a demo. They are small jobs, but they interrupt your flow when you have to hunt for a decent tool each time.
Here are nine utilities I use regularly, all gathered on Toolharo, plus tips on when each one is worth opening.
- JSON Formatter
You’ve pasted an API response, and it’s one unreadable line. A JSON formatter indents it so you can see the structure at a glance.
Use it when: debugging an API response, reading a config file, or writing documentation examples.
- JSON Validator
Formatting shows you the shape, while validating tells you whether the JSON is actually correct. A JSON validator points out problems like trailing commas, missing quotes or unclosed brackets.
Use it when: a request fails with a parse error and you can’t spot why. The usual culprits are a trailing comma or single quotes instead of double quotes.
- Base64 Encoder / Decoder
Base64 turns up in data URIs, basic auth headers, email attachments and token payloads. A quick Base64 tool saves you from opening a terminal for a one-off decode.
Use it when: inspecting a header or embedding a tiny image as a data URI.
Remember: Base64 is an encoding, not encryption. Never treat it as a way to protect secrets.
- Password Generator
A password generator is useful for test accounts, staging environments and seed data. Choose long passwords with mixed character types.
Use it when: creating credentials for non-production setups. For real production secrets, use a proper secrets manager.
- QR Code Generator
QR codes aren’t only for marketing. I use a QR code generator to share a staging URL with testers on phones, open a mobile deep link, or hand someone a Wi-Fi login at a meetup.
Use it when: you need to move a link from your laptop to a phone without typing it.
- Robots.txt Generator
A mistake in robots.txt can quietly keep search engines away from your whole site. A robots.txt generator gives you the correct syntax for allow and disallow rules.
Use it when: launching a new site, or blocking admin and staging paths.
Always re-check the file before deploying. A stray Disallow: / is a classic launch-day mistake.
- Sitemap Generator
For small projects, a sitemap generator is the fastest way to produce an XML sitemap you can submit to search engines.
Use it when: shipping a portfolio, landing page or small static site that doesn’t generate sitemaps automatically.
- Text Diff Checker
Comparing two blocks of text by eye is slow and error-prone. A text diff checker highlights what changed between two versions of a config, a copy block or a log excerpt.
Use it when: you suspect a copy-paste changed something, or you need to compare two outputs outside of Git.
- Image Compressor
Large images are one of the most common causes of slow pages. An image compressor shrinks files before you add them to a project.
Use it when: adding hero images, screenshots or thumbnails to a site. Compare the file size before and after, and check the result visually before shipping.
Honorable mentions
A few more that come in handy:
Case Converter for switching text between camelCase, snake_case, uppercase and more (confirm the supported formats before listing them)
Find & Replace for quick bulk edits on pasted text
Lorem Ipsum Generator for placeholder copy in mockups
Favicon Generator for turning one image into the sizes a site needs
A simple way to work with small tools
A few habits make these tools safer and more useful:
Don’t paste secrets. Even if a tool runs in your browser, avoid pasting real API keys, tokens or customer data into any online utility. Use dummy values. [Add a note here if you can confirm which Toolharo tools process data entirely in the browser.]
Verify the output. Treat generated results, like a robots.txt file or an XML sitemap, as a first draft and check them before deploying.
Bookmark a collection, not a hundred links. One organized place beats a messy bookmarks bar.
Wrapping up
None of these tools are glamorous, but together they save a lot of small interruptions. The best utility is the one that gets out of your way and lets you finish the task.
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