The Free Developer Tools Worth Keeping in Your Bookmarks

Most of a developer’s day is made of small tasks. You paste a JSON response to read it, decode a Base64 token to see what is inside, generate a throwaway password, or check what IP a request is coming from. None of these deserve a heavy desktop app or an account, they deserve a fast browser tab that does one thing well and gets out of the way.

Here are the small, free utilities that genuinely earn a bookmark, with a note on when each one is the right tool to reach for. A useful side benefit of browser-based tools: when the work happens locally on your machine, your data never gets uploaded to someone else’s server.

JSON Formatter, for when the response is one unreadable line

Copy a payload out of a network tab and it arrives as a single thousand-character line. A formatter turns it into indented, readable structure so you can actually find the field you need, and validation tells you exactly where the syntax broke instead of failing silently. This is probably the tool you will open most often. Reach for it any time you are debugging an API or cleaning up a config file before committing.

Base64 Encoder/Decoder, for tokens and data URIs

Base64 shows up everywhere: JWT payloads, CSS data URIs, API fields full of encoded strings. A good encoder handles UTF-8 properly, including emoji and non-Latin characters that plain btoa and atob tend to mangle. Use it to peek inside a token or to encode a small blob for transport. Just remember Base64 is encoding, not encryption; anyone can decode it.

Password Generator, for unique, genuinely random secrets

When you need a strong password for a new account or a service credential, do not invent one in your head. A generator that uses the browser’s cryptographically secure random source produces something far harder to guess than anything you would type. Set the length to 16 or more, generate, and paste it straight into your password manager. The whole point is that you never have to remember it.

IP Lookup, for "where is this request coming from?"

Whether you are confirming your VPN is actually masking your address, debugging a geo-targeted feature, or investigating a suspicious login, an IP lookup gives you the location, ISP, and network details behind an address. Geolocation is approximate, city-level at best, and VPNs report the exit node, but for most debugging that is exactly the detail you need.

Text Tools, for the small string chores

Converting a heading to title case, counting words against a limit, stripping extra whitespace from pasted content, these tiny chores come up constantly and do not justify opening a word processor. A bundled text toolkit with live word and character counts handles them in one place. Handy for writing meta descriptions, social posts, or quick SQL string tweaks.

URL Tools, for encoding, decoding, and parsing links

URLs have strict rules about which characters are allowed, and getting encoding wrong breaks links and corrupts API requests. URL tools let you encode text for a query string, decode percent-encoding back to readable form, validate structure, and break a long URL into its parts. Indispensable when you are debugging redirect chains or untangling tracking parameters.

QR Code Generator, for menus, demos, and handoffs

Sometimes you just need a scannable square, a staging URL for a teammate to open on their phone, a link on a slide, or a contact card. A generator that builds the code in the browser produces a static PNG that never expires and never routes through a third-party service, so you can encode private URLs without them being logged anywhere.

Color Picker, for HEX, RGB, and HSL without the math

Design work means constantly converting between color formats. A picker that shows HEX, RGB, and HSL together, updating live as you drag or type, saves you from doing the conversion by hand or guessing. Click to copy the format your CSS or design tool expects and move on.

Why small browser tools beat heavyweight apps for these jobs

There is a real argument for keeping these tasks in lightweight, single-purpose tools. They load instantly, they do not need installing or updating, and the good ones process everything locally so sensitive input never leaves your machine. For the small, frequent jobs that fill a developer’s day, that combination of speed and privacy beats firing up a large application every time.

Bookmark the two or three you reach for most, and the next time you need to format a payload or generate a password, it is one click away instead of a search-and-hope.