Skip to content

100+ developer utilities

Home All Tools About FAQ Contact Privacy

Fast & free

Browse

Search and browse categories

JSON Tools

JSON Formatter

Format and beautify JSON

JSON Validator

Validate JSON input

JSON Minifier

Minify JSON

JSON Compare

Compare two JSON documents side by side and highlight differences

JSON to CSV

Convert JSON to CSV

JSON to XML

Convert JSON to XML

JSON to YAML

Convert JSON to YAML

JSON Keys Extractor

Extract all keys from JSON

JSON Size Calculator

Calculate JSON size

Base64 Tools

Base64 Decoder

Decode Base64 to text

Base64 Encoder

Encode text to Base64

Base64URL Decoder

Decode URL-safe Base64 to text

Base64URL Encoder

Encode text to URL-safe Base64

Base64 to Image Preview

Preview an image from a Base64 data URL

JWT Tools

JWT Decoder

Decode JWT payload

JWT Header Decoder

Decode JWT header

Regex Tools

Regex Tester

Test a regex pattern from line 1 against the remaining text

Regex Replace

Replace matches using line 1 pattern, line 2 replacement, and the remaining text

Regex Validator

Validate a regular expression

Regex Match Extractor

Extract regex matches using line 1 pattern and the remaining text

Email Extractor

Extract email addresses from text

URL Extractor

Extract URLs from text

Phone Extractor

Extract phone numbers from text

Regex Escape

Escape special regex characters

UUID Tools

UUID Generator

Generate a UUID

UUID Validator

Validate UUID strings

URL Tools

URL Parser

Break a URL into readable parts

URL Decoder

Decode URL-encoded text

URL Encoder

Encode text for URLs

Query String Parser

Convert a query string to JSON

Query String Builder

Convert JSON to a query string

URL to Base64

Fetch an image URL and convert it into Base64

Password Tools

Password Strength Checker

Analyze password strength, entropy, and common risk patterns

Strong Password Generator

Generate strong high-entropy passwords with required character variety

Random Password Generator

Generate configurable passwords with secure browser randomness

PIN Generator

Generate numeric PINs with secure browser randomness

Hash Tools

SHA256 Hash Tool

Generate and verify SHA-256 digests for integrity workflows

MD5 Hash Tool

Generate and verify MD5 digests for legacy checksum workflows

Bcrypt Hash Tool

Generate and verify bcrypt password hashes with configurable cost factors

SHA512 Hash Tool

Generate and verify SHA-512 digests for long-form integrity workflows

SHA1 Hash Tool

Generate and verify SHA-1 digests for legacy interoperability workflows

HMAC Generator

Generate and verify keyed HMAC digests for signed message workflows

File Hash Checker

Hash uploaded files in the browser and compare them against known checksums

Hash Compare

Hash plain text and compare it against an expected digest

CRC32 Checksum

Generate and verify CRC32 checksums for non-cryptographic integrity checks

SQL Tools

SQL Formatter

Format SQL queries for easier reading

SQL Minifier

Minify SQL queries

CSV Tools

CSV to JSON

Convert CSV data into a JSON array

CSV Formatter

Format and normalize CSV while preserving quoted values

CSV Validator

Validate CSV row and column consistency

XML Tools

XML Formatter

Format and beautify XML with proper indentation

XML Validator

Validate XML syntax and report line-level errors

XML to JSON

Convert XML to formatted JSON

YAML Tools

YAML Formatter

Format YAML with standardized indentation

YAML Validator

Validate YAML syntax and structure

YAML to JSON

Convert YAML to formatted JSON

Markdown Tools

Markdown Preview

Render Markdown as HTML output

Markdown to HTML

Convert Markdown into HTML

Markdown Formatter

Clean up Markdown spacing

Markdown Table Generator

Build Markdown tables with editable rows, columns, alignment, and CSV import

Markdown Link Generator

Generate a Markdown link from line 1 text and line 2 URL

Markdown List Generator

Turn plain lines into a Markdown list

Markdown Image Generator

Generate a Markdown image from line 1 alt text and line 2 URL

Date Tools

Date to Timestamp

Convert a date into a Unix timestamp

Days Between Dates

Calculate the number of days between two dates

Time Duration Calculator

Calculate the duration between two dates

Timezone Converter

Show UTC and local time for a date value

Age Calculator

Calculate age from birth date

ISO Date Formatter

Convert a date into ISO 8601 format

Color Tools

Color Picker

Pick a color and inspect the selected value

HEX to RGB

Convert HEX colors to RGB

RGB to HEX

Convert RGB colors to HEX

RGB to HSL

Convert RGB colors to HSL

HSL to RGB

Convert HSL colors to RGB

RGB to CMYK

Convert RGB colors to CMYK

Color Name to Code

Convert named colors into Hex, RGB, HSL, CMYK, and HCL

Tailwind Color Palette Generator

Browse a small Tailwind-style color palette preview

CSS Tools

CSS Formatter

Format CSS code for easier reading

CSS Minifier

Minify CSS code

Border Radius Generator

Create CSS border-radius values with a live preview

Box Shadow Generator

Create CSS box-shadow values with a live preview

Gradient Generator

Create linear gradients with a live preview

Clip Path Generator

Create CSS clip-path values with a live preview

CSS Unit Converter

Convert between px, rem, em, vh, vw, pt, pc, and percent

CSS Color Extractor

Extract colors from CSS

CSS Property Extractor

Extract CSS properties

Text Analysis

Word Counter

Count words in text

Character Counter

Count all characters

Character Counter Without Spaces

Count characters excluding spaces

Sentence Counter

Count sentences in text

Line Counter

Count lines in text

Paragraph Counter

Count paragraphs in text

Reading Time Calculator

Estimate reading time

Average Word Length

Calculate average word length

Frequent Words

Extract the most frequent words

Remove Empty Lines

Remove blank lines from text

Remove Punctuation

Remove punctuation from text

Random Text Generator

Generate random alphanumeric text with secure browser randomness

Text to Hex

Convert text to hexadecimal

String Tools

Uppercase Converter

Convert text to uppercase

Lowercase Converter

Convert text to lowercase

Sentence Case Converter

Convert text to sentence case

Capitalize Words

Capitalize each word

Reverse String

Reverse the input text

Random String Generator

Generate a random alphanumeric string with secure browser randomness

Number Tools

Percentage Calculator

Calculate what percentage one number is of another

Percentage Change Calculator

Calculate percentage increase or decrease between two values

Average Calculator

Calculate the average of a number list

Decimal to Binary

Convert decimal numbers to binary

Prime Number Checker

Check whether an integer is a prime number

Factorial Calculator

Calculate the factorial of a non-negative integer

Roman Numeral Converter

Convert numbers to Roman numerals and Roman numerals to numbers

HTML Entity Tools

HTML Encoder

Encode HTML entities

HTML Decoder

Decode HTML entities

HTML to Markdown

Convert HTML into Markdown

SVG Tools

SVG Preview

Preview raw SVG markup in the browser

SVG to JSX

Convert SVG markup to JSX for React

SVG to CSS

Convert SVG to CSS background-image

SVG to Data URI

Convert SVG markup to a URL-encoded data URI

SVG Minifier

Minify SVG markup by removing comments and extra whitespace

Image Tools

Image to Base64

Convert an uploaded image into a Base64 data URL

SEO Tools

Open Graph Generator

Generate Open Graph meta tags from structured page metadata

Slug Generator

Slug Generator

Convert text to a URL slug

Timestamp Tools

Timestamp to Date

Convert timestamp to UTC date

Timestamp to Local Date

Convert timestamp to local date

Unix Timestamp Generator

Generate current timestamp

Unicode Tools

Unicode Decoder

Decode Unicode escape sequences

Unicode Encoder

Encode text as Unicode escape sequences

ASCII Tools

ASCII Decoder

Convert ASCII codes to text

ASCII Encoder

Convert text to ASCII codes

Binary Tools

Binary Decoder

Convert binary to text

Binary Encoder

Convert text to binary

Binary to Decimal

Convert binary numbers to decimal

Hex Tools

Hex to Text

Convert hexadecimal to text

ROT13 Tools

ROT Encoder

Encode text with ROT13, ROT5, ROT18, ROT47, and custom Caesar shifts

ROT Decoder

Decode ROT13, ROT5, ROT18, ROT47, and inspect Caesar shifts

100+ developer utilities

Product

Home All Tools About FAQ Contact

Tools

Browse All Tools

Legal

Privacy Policy Terms Cookie Policy Disclaimer

© 2026 FreeToolkit. Built for fast, focused development.

Ads Disclosure Editorial Policy

Home
All Tools
Query String Builder

Tool workspace

Query String Builder

Build query strings from JSON instantly. Convert structured data into URL query parameters for APIs and web requests.

url input

1

2

3

4

5

6

7

8

9

10

11

12

1 line0 chars

Output

Read only

Output will appear here...

Action panel

Query String Builder

Convert JSON to a query string

Status

Waiting for input

Query String Builder converts JSON objects into URL query strings. This makes it easier to generate URL parameters for APIs, web applications, and HTTP requests.

How to Use

Paste JSON data into the editor.
Click Run Tool.
The tool converts JSON into a query string.
Copy the generated URL parameters.

Example

Input

{"name":"John","age":30}

Output

name=John&age=30

Explanation

Each key-value pair in the JSON object becomes a parameter in the query string separated by "&".

FAQ

What is a query string?

A query string is a set of parameters appended to a URL.

Where is it used?

It is commonly used in HTTP GET requests.

Can nested JSON be converted?

Nested structures may require flattening.

Does the tool encode parameters?

Yes special characters are URL encoded.

Is this tool secure?

Yes data remains in your browser.

Can multiple parameters be generated?

Yes any number of JSON fields can become parameters.

Related Tools

Query String Parser URL Encoder URL Decoder