Base64 Encode Decode Offline vs JWT & Base64 Decoder/Verifier

Paste a Base64 string, tap once, read the answer — right on your iPhone, fully offline. No web converter, no upload, no wondering who just logged the token you pasted. Base64 Encode Decode Offline is a developer scratchpad built for the real thing you paste: blobs copied out of logs and terminals. The decoder tolerates URL-safe alphabets, missing padding and line-wrapped copy-paste, auto-detects whether you meant encode or decode, and refuses garbage instead of returning silent nonsense. URL decoding is byte-accurate, so a leading BOM or odd byte is preserved instead of being quietly eaten. Everything renders in a proper monospaced font. WHAT YOU GET • A wrapped, unpadded, URL-safe Base64 blob from a log file still decodes cleanly — whitespace, CRLF and base64url handled for you • Paste a JWT and read its pretty-printed header and payload immediately — the signature never touches a server • One input, four digests: MD5, SHA-1, SHA-256 and SHA-512 update as you type, with one button to copy all four • URL-encode a query value and the &, =, + and # characters that break query strings are actually escaped • Turn any file into Base64 or a ready-to-embed data URI with the correct MIME type — and turn Base64 back into a file • The String Inspector shows characters, UTF-8 / UTF-16 / UTF-32 byte counts, words and lines the moment text is entered PERFECT FOR • Backend and mobile developers debugging an API payload away from the laptop • QA engineers inspecting auth tokens without pasting credentials into a website • Sysadmins decoding config blobs and verifying checksums from a phone session • Students seeing exactly how encodings and hash digests behave WHY NOT JUST USE A WEB CONVERTER? Because every online encode/decode tool receives your string on its server — and the strings developers convert are exactly the ones that should never leave the machine: session tokens, API keys, connection strings, JWTs. This app does all conversion and hashing on the device with Apple's CryptoKit. It works in airplane mode. PRIVATE BY DEFAULT No accounts, no tracking of your content, no network needed to convert. Your inputs and your conversion history are stored only on your iPhone. FULL ACCESS Pro unlocks unlimited saved conversions, file conversion beyond 5 MB in both directions, and Batch mode to convert many lines in one pass. Full access is available as a weekly subscription, a yearly subscription, or a one-time lifetime purchase. Decode that string before the next station — download Base64 Encode Decode Offline. Terms of Use: https://leanstudio.asia/terms-of-use Privacy Policy: https://leanstudio.asia/privacy-policy Support: support@leanstudio.asia

JWT Decoder, Encoder & Verifier is the JSON Web Token companion your phone has been missing. Paste a token and instantly see its header, payload, and claims decoded - then verify its signature, sign your own, or convert Base64 back and forth. Everything runs on the device. No accounts, no network calls, nothing stored. 100% OFFLINE, NOTHING LEAVES YOUR DEVICE Tokens often carry sensitive data, so this app never uploads them. All parsing, verification, signing, and Base64 work happens locally. There is no server, no logging, and no analytics on the content you paste. It is the safe way to inspect a production token on your phone. DECODE - Live decoding as you type or paste - no "decode" button needed - Pretty-printed JSON for both the header and the payload - Time claims (iat, nbf, exp) shown as readable UTC, with EXPIRED and "not yet valid" badges - Raw Base64URL signature segment displayed separately - Clear, specific errors for malformed tokens VERIFY SIGNATURES - HMAC: HS256, HS384, HS512 with a shared secret (raw or Base64 key) - RSA: RS256, RS384, RS512 (RSASSA-PKCS1-v1.5) with a PEM public key - RSA-PSS: PS256, PS384, PS512 with a PEM public key - ECDSA: ES256, ES384, ES512 with a PEM public key - The input automatically switches between secret and PEM based on the token's algorithm, and the result clearly states valid, invalid, or why it could not be checked SIGN AND GENERATE - Build and HMAC-sign a JWT from any JSON payload (HS256/384/512) - One-tap "Generate key pair" creates a throwaway RSA or EC key for testing, fills the private key, and shows the public key to copy straight into the Verify tab - a complete sign-then-verify loop, entirely on device BASE64 TOOLBOX - Encode and decode standard Base64 and URL-safe Base64URL - Optional padding control - Falls back to a hex view when decoded bytes are not valid UTF-8 text BUILT FOR ENGINEERS - Paste straight from the system clipboard with one tap - Load a built-in example to see how each tool works - Copy any result to the clipboard - Monospace, selectable output throughout POLISHED TO MATCH YOUR PHONE - Native Material Design 3 interface - Light and dark themes that follow the system setting - Localized in English, Traditional Chinese, Simplified Chinese, and Japanese WHO IT IS FOR - Backend and mobile developers debugging auth tokens - Security engineers inspecting and verifying JWTs - QA and support teams checking expiry and claims - Anyone who needs to decode a token without pasting it into a website A note on standards: this tool reads and verifies tokens; it is an inspection and testing utility, not a secrets manager. Keys you paste or generate stay on the device and are never transmitted. JWT Decoder, Encoder & Verifier is fast, private, and made for real debugging. Install it once and stop pasting tokens into random web decoders.