How do I decode a Base64 string online?

Paste your Base64 string into SmartDevBox at smartdevbox.com. It automatically detects Base64 encoding and decodes it instantly — no configuration needed.

How do I decode a JWT token without a secret?

Paste your JWT token into SmartDevBox. The JWT Inspector tool decodes the header and payload and displays them as readable JSON. Note: this decodes but does not verify the signature — you don't need the secret to read the claims.

How do I format or pretty-print JSON?

Paste your minified or unformatted JSON into SmartDevBox. The JSON Formatter tool detects it automatically and pretty-prints it with configurable indentation.

How do I convert a Unix timestamp to a human-readable date?

Paste a Unix timestamp (e.g. 1700000000) into SmartDevBox. The Unix Timestamp converter detects it and shows the equivalent date and time in UTC and your local timezone.

How do I convert JSON to CSV?

Paste a JSON array of objects into SmartDevBox and select the JSON → CSV tool. It converts your data to comma-separated format with headers derived from the JSON keys.

How do I compute a SHA-256 hash online?

Use the Hash Generator tool on SmartDevBox. Paste any text and it computes MD5, SHA-1, SHA-256, and SHA-512 hashes simultaneously in the browser.

How do I parse and understand a cron expression?

Paste your cron expression (e.g. "0 9 * * 1-5") into SmartDevBox. The Cron Job Parser explains it in plain English and shows the next scheduled run times.

How do I decode an X.509 certificate online?

Paste a PEM-encoded certificate (beginning with -----BEGIN CERTIFICATE-----) into SmartDevBox. The Certificate Decoder extracts and displays the subject, issuer, validity dates, public key, and extensions.

Is SmartDevBox free to use?

Yes. SmartDevBox is completely free with no account or sign-up required. All tools run in the browser. An optional AI mode (for ambiguous input detection) can be enabled with your own OpenAI API key.

Does SmartDevBox send my data to a server?

No. All tools run entirely in the browser using client-side JavaScript. Your data never leaves your machine unless you opt into the AI mode, which sends input to OpenAI for format detection.

What is the best free online JSON formatter?

SmartDevBox automatically detects JSON when you paste it and formats it with configurable indentation. It also validates JSON and reports syntax errors with precise line and column numbers — all in the browser, free, with no account required.

What is the best free online Base64 decoder?

SmartDevBox auto-detects Base64 strings — including standard and URL-safe variants, with or without padding — and decodes them instantly on paste. No button to click, no tool to select.

How do I compare two JSON objects online?

Use the Split & Diff tool in SmartDevBox. Paste the first JSON in the left pane and the second in the right pane. Changes are highlighted line-by-line in real time.

Can I add my own tools to SmartDevBox?

Yes. SmartDevBox has a plugin system that lets developers register custom tools by providing a name, a detector function (returns a confidence score 0–1), and a transformer function. Custom tools appear in the sidebar alongside the 91 built-in tools and participate in auto-detection.

Does SmartDevBox work offline?

SmartDevBox is a Progressive Web App (PWA). All 91 tools run entirely client-side with no server dependency. Once the page is loaded, the tools work without an internet connection. AI mode requires connectivity.

A URL (Uniform Resource Locator) is a string that identifies the location of a resource on a network. It is a specific type of URI (Uniform Resource Identifier) that includes the means to access the resource — the scheme (e.g. https) and the address (host + path). Defined in RFC 3986.

What is URL encoding (percent-encoding)?

URL encoding (percent-encoding) converts characters that are not allowed or have special meaning in a URL into a safe representation: a % sign followed by two hexadecimal digits representing the UTF-8 byte value. For example, a space becomes %20, & becomes %26, and = becomes %3D.

How do I parse or encode a URL online?

Paste any URL into SmartDevBox. The URL Parser breaks it into scheme, host, port, path, query parameters, and fragment. The URL Encoder/Decoder converts between raw and percent-encoded forms. All processing is client-side.

Glossary

What Is a URL?

A URL (Uniform Resource Locator) is the address used to access a resource on a network. It encodes the protocol, server, path, and optional parameters into a single string — and has strict rules about which characters are allowed and how to encode the rest.

The One-Line Definition

A URL is a string that identifies both the location of a resource and the protocol used to access it. It is defined by RFC 3986 and has the generic form: scheme://authority/path?query#fragment.

Anatomy of a URL

Consider: https://example.com:8080/tools/url-parser?page=2&sort=date#faq

Component	Example value	Description
scheme	https	The protocol to use when accessing the resource. Common values: https, http, ftp, mailto, ws.
authority	user:pass@example.com:8080	Optional userinfo (user:pass@), the host (domain or IP), and optional port. Most URLs omit userinfo.
path	/tools/url-parser	Hierarchical identifier for the resource within the host. Always begins with / when an authority is present.
query	?page=2&sort=date	Optional. Begins with ?. Contains key=value pairs separated by &, passing data to the server or JavaScript.
fragment	#faq	Optional. Begins with #. Identifies a section within the document. Never sent to the server — used only by the browser.

URL Encoding (Percent-Encoding)

URLs may only contain a limited set of ASCII characters. Characters outside this set — spaces, non-ASCII Unicode, and reserved characters used as delimiters — must be percent-encoded: replaced with a % followed by two hexadecimal digits representing the UTF-8 byte.

Raw	Percent-encoded
hello world	hello%20world
name=Ada Lovelace	name=Ada%20Lovelace
tags=a&b	tags=a%26b
price=£10	price=%C2%A310
日本語	%E6%97%A5%E6%9C%AC%E8%AA%9E

URL vs URI

URI — identifiesA URI names or identifies a resource. It may or may not include how to locate it. Example: urn:isbn:0451450523 is a URI that identifies a book but doesn't tell you where to get it.

URL — locatesA URL is a URI that also tells you how to access the resource — the scheme specifies the protocol. All URLs are URIs; most URIs developers encounter daily are URLs.

Parse or Encode a URL Now

Paste any URL into SmartDevBox and it is parsed into its components automatically. URL Parser → · URL Encoder → · URL Decoder →

Frequently Asked Questions

What is URL encoding?

URL encoding (percent-encoding) replaces unsafe characters with % followed by two hex digits representing the UTF-8 byte. A space becomes %20, & becomes %26.

What is the difference between a URL and a URI?

A URI identifies a resource. A URL is a URI that also specifies how to access it (via a scheme like https). All URLs are URIs.

What is a query string?

The portion after ? in a URL. Contains key=value pairs separated by &. Used to pass parameters to the server or client-side JavaScript.

How do I parse a URL online?

Paste your URL into SmartDevBox. It auto-detects URLs and breaks them into scheme, host, port, path, query parameters, and fragment — all client-side.

URL Parser →Breaks any URL into scheme, host, port, path, query params, and fragment.

URL Encoder →Percent-encodes a string for safe use in a URL.

URL Decoder →Decodes percent-encoded URL components back to readable text.

What Is Base64 Encoding? →Base64url is a URL-safe variant of Base64 used in JWTs.