URL Encoder & Decoder
Client-sideFree & FastEncode and decode URLs, URI components, and inspect query parameters.
Relevant Developer Workflows
URL Encoder & Decoder makes it easy to work with OAuth authorization redirects, UTM campaign tags, and encoded API parameters. Decoded a JSON object from a query parameter?
How to use the URL Encoder & Decoder
- 1Choose your encoding mode: 'encodeURIComponent' for query parameter values (encodes special characters like &, =, ?), 'encodeURI' for complete URLs, or 'Form / Query' for application/x-www-form-urlencoded formats.
- 2Paste your text, URL, or encoded string into the Input panel.
- 3Click 'Encode' to percent-encode characters, or 'Decode' to revert percent sequences (like %20 or %2F) back to human-readable text.
- 4Switch to the 'Parameters' tab to inspect every query parameter parsed into a dedicated key-value table. You can edit, add, or delete query parameters and update the URL instantly.
- 5Click 'Copy Output' to copy the converted result to your clipboard.
Practical Use Cases
OAuth Authorization & Callback URL Preparation
Properly percent-encode complex redirect URLs (such as redirect_uri parameters) in OAuth authorization requests or inspect callback query parameters without character truncation or delimiter collisions.
redirect_uri=https%3A%2F%2Fmyapp.dev%2Foauth%2Fcallback“The endpoint URI MUST NOT include a fragment component, and parameters MUST be percent-encoded per RFC 3986.”
Inspecting & Editing UTM Campaign Tracking Parameters
Parse, verify, and adjust marketing or analytics query strings containing UTM tracking parameters (such as utm_source, utm_medium, utm_campaign) using the visual parameter table.
?utm_source=devtoolnest&utm_medium=web&utm_campaign=launchDecoding JSON Payloads Embedded in Query Parameters
Decode URL-encoded JSON payloads passed inside query strings (such as filter, config, or state parameters) so you can review their contents in plain text.
?filter=%7B%22status%22%3A%22active%22%7D -> ?filter={"status":"active"}“Decodes a Uniform Resource Identifier (URI) component previously created by encodeURIComponent.”
Inspecting and Editing Query Parameters in a Table
Switch to the Parameters tab to inspect extracted query parameters in an editable key-value table. Update parameter values or add new ones and rebuild the full URL string automatically.
Frequently Asked Questions
What is the difference between encodeURI and encodeURIComponent?
encodeURI is designed for complete URLs and does not encode reserved characters that have grammatical meaning in a URL (such as :, /, ?, #, &, =). encodeURIComponent is designed for individual query string values and encodes all reserved delimiters so they do not break URL structure.
“URL parsing handles distinct delimiters separating protocol, host, path segments, and query parameters.”
Why are spaces sometimes encoded as '+' instead of '%20'?
In standard URI percent-encoding (RFC 3986), a space is encoded as '%20'. However, in HTML forms (application/x-www-form-urlencoded), spaces are traditionally replaced by '+'. DevToolNest supports both methods.
“Space characters are replaced by '+' in form submission data, whereas RFC 3986 mandates %20.”
Can this tool handle unicode and foreign characters?
Yes! Modern browsers encode UTF-8 multi-byte characters into standard hexadecimal percent sequences (for example, emojis and non-Latin alphabets like Japanese or Cyrillic).
Does DevToolNest log or track the URLs I enter?
No. All operations run directly in your browser JavaScript thread. We never store, log, or send your URLs, auth tokens, or search parameters.
Technical Glossary & Definitions
Key concepts, specifications, and parameters defined in accordance with web standards:
- Percent-Encoding
- A mechanism defined in RFC 3986 to represent arbitrary character octets in a URI using '%' followed by two hexadecimal digits.
- Reserved Characters
- Characters with special syntactic meaning in URIs (such as :, /, ?, #, &, =) that must be escaped when used as data.
- encodeURIComponent()
- JavaScript standard library function that encodes all URI characters except A-Z, a-z, 0-9, -, _, ., !, ~, *, ', (, ).
- encodeURI()
- JavaScript function encoding complete URIs while preserving reserved path, host, and query boundary delimiters.
- URLSearchParams
- Modern WHATWG Web API interface providing utility methods to read, edit, and serialize URL query parameters.
Authoritative Standards & Documentation
Primary specifications, IETF RFC standards, and verifiable technical documentation referenced by this tool:
RFC 3986: Uniform Resource Identifier (URI) Syntax
The authoritative internet standard for URI syntax, percent-encoding mechanisms, and reserved delimiter rules.
WHATWG URL Living Standard
Modern browser specification for URL parsing, URLSearchParams, host serialization, and percent-encoding sets.
MDN Web Docs: encodeURIComponent()
Complete developer documentation for escaping URI components, character sets, and UTF-8 surrogate pair handling.
MDN Web Docs: encodeURI()
Technical reference on preserving full URI delimiters including protocol schemes, slashes, and query markers.
RFC 6749: The OAuth 2.0 Authorization Framework
Defines requirements for query parameter encoding in OAuth authorization redirects and state verification.
W3C Forms: application/x-www-form-urlencoded
Specifies HTML form submission encoding conventions, including plus '+' space substitution.
In-Browser Execution & Security Architecture
Every operation performed on this page runs exclusively on your client device using modern browser web standards. Understanding how in-browser execution differs from traditional cloud-hosted developer utilities is essential for security-conscious software engineers:
Zero-Knowledge Local Sandbox
Unlike conventional web utilities that upload your payloads to a remote backend API for processing, DevToolNest executes native JavaScript algorithms directly in your browser's virtual machine (V8 on Chrome/Edge/Brave, JavaScriptCore on Safari, or SpiderMonkey on Firefox). Your tokens, keys, customer data, and JSON schemas never traverse the public internet or touch intermediate proxy caches.
Sub-Millisecond JIT Performance
Local execution eliminates HTTP round-trip latencies, TCP handshakes, TLS negotiation overhead, and cloud queue bottlenecks. Format 10MB payloads, parse deeply nested JSON objects, or decode thousands of tokens with instantaneous response times powered by native WebAssembly and optimized JavaScript JIT compilation.
Transient Memory & Ephemeral State
All parsed syntax trees, string buffers, and diff trees reside strictly within the ephemeral memory space of your browser tab. No persistent cookies, WebSQL, or remote databases store your computations. Closing the tab immediately releases all memory allocations, leaving zero residual footprint on external servers or local disk.
Strict RFC Standards Compliance
Our formatting and parsing logic conforms strictly to authoritative internet specifications including IETF RFC 8259 (JSON), RFC 7519 (JWT), RFC 3986 (URI), RFC 4648 (Base64), and YAML 1.2. This ensures that outputs generated in DevToolNest are 100% interoperable with production systems running Node.js, Go, Python, Java, and Rust.
Privacy Commitment
At DevToolNest, privacy is engineered into the code. This tool executes 100% locally in your web browser. No JSON payloads, URLs, API responses, or sensitive tokens are ever transmitted across the internet to our or any third-party servers.
“Client-side isolation eliminates data-in-transit risks and complies with zero-trust confidentiality mandates.”
Author & Technical Reviewer
Seasoned professional with over 5 years of experience in the IT industry specializing in Mobile and Web Development, strategic planning, project management, and delivering high-performance, user-centric digital tools.