Encoders, decoders, and validators
9 tools in this category. Each runs in your browser.
Working with text formats means moving values between systems that have different rules about what is safe to include. Encoders translate values into safe forms; decoders reverse the translation; validators check that an input matches a format rules without modifying it.
The tools below cover the encoding systems that matter most in everyday work: URL percent-encoding for query parameters, Base64 for binary-in-text transport, HTML entities for safe markup, JSON for structured data, JWT for signed tokens, IP and CIDR for network identifiers, Kubernetes manifests for cluster config, TOML for hand-written config files, and ROT13 (which is not encryption but is the historical convention for spoiler hiding on text-only forums).
The common thread: each one runs entirely in your browser. Nothing is uploaded, nothing is logged, nothing is sent to a server you do not control. Even cryptography-adjacent tools (hashes, JWT decoding, ROT13) keep your input on your machine. The result: you can paste sensitive values, reload the page, or close the tab and your input is gone forever.
Pick a tool below to start. If you are decoding a value you copied from somewhere, the decoder is usually the right starting point. If you are preparing a value to put somewhere, the encoder is. When a tool flags an error, the message tells you which character or which structure violated the format rules.
All 9 tools in this category
URL encoder / decoder
Percent-encode strings for URLs.
Base64 encoder / decoder
Standard or URL-safe base64.
HTML entity encoder / decoder
Named or numeric entities.
JSON formatter / validator
Format, validate, minify JSON.
JWT decoder + claims explainer
Decode JWTs and explain standard claims.
IP address validator (IPv4 + IPv6)
Validate addresses and compute CIDR subnets.
Kubernetes manifest validator
Quick structural pre-check for k8s YAML.
TOML formatter / validator
Validate and reformat TOML.
ROT13 / Caesar cipher
Adjustable shift cipher (toy, not security).
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