toolbook.io

ToolBook's developer side covers the jobs you hit most often: JSON formatting and validation, JWT decoding, Base64 encoding, hashing, URL encoding, and converters for XML, YAML and CSV. The key detail is where the work happens. The JWT decoder, hash generator and Base64 tool all run client-side, so a token or key you paste stays in your browser. For anyone handling credentials, that is the difference between a useful tool and a risky one.

The calculator shelf spans health, time, money and math. You get percentage, age, BMI, calorie and TDEE, tip, discount and aspect ratio tools, all with live results. Each one shows the working, not just the final number, so you can see how the answer was reached. That makes them useful for checking your own math rather than trusting a black box.

The text section handles the chores that pile up around writing. There is a word and character counter, case converter with 14 formats, a find-and-replace with regex, a duplicate line remover, a line sorter with eight modes, and a text diff checker. The diff tool compares two versions side by side and highlights additions, removals and word-level edits, which is handy for reviewing an edit pass without a Git repo.

ToolBook groups its SEO tools so you can inspect a page without leaving for another site. The checks cover the on-page basics that decide how a page shows in search, and they sit next to the developer and text tools rather than in a separate product. For a writer or a small site owner, that keeps the workflow in one place.

The finance set is built around decisions, not just outputs. Mortgage, loan repayment, compound interest, retirement and savings goal calculators cover the global side, while a cluster of India-specific tools handles SIP, EMI, FD, PPF, RD, HRA and income tax. Each one breaks the result down year by year or month by month, so you can see where the money goes instead of staring at one total.

The image compressor and resizer work on JPEG, PNG and WebP, and both process your files on your device. That means a photo you shrink or crop is never sent to a server. For anyone working with client images or personal photos, keeping the file local removes the usual worry about what a free tool does with your uploads.

The whole site is built around not collecting what it does not need. There is no signup, no email wall and no cookie banner chasing you for consent to tracking you are not running. Support runs through Ko-fi donations instead of ads, so the page you came for is not buried under five ad slots. For a free tool, that is a rarer combination than it should be.