Online decoder tools that turn noise into meaning.
Decode Base64, JWTs, hex, URLs, ciphers, certificates, packets and IDs — free, instantly, and without a single byte leaving your machine. Built for developers, security researchers and sysadmins.
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- 90
- decoders catalogued
- 48
- live right now
- 0
- bytes sent to a server
- 9
- tool categories
A free online decoder for every format you meet
decoder.tools is a collection of 90 browser-based decoders and parsers that turn encoded, encrypted or binary data back into something readable. Paste a Base64 string, a JSON Web Token, a percent-encoded URL, a hex dump, an X.509 certificate, a packet header or a VIN, and read the decoded result immediately — no account, no upload, no command line.
Every tool is pure client-side JavaScript. Your input is processed in the page you are looking at, never transmitted to a server and never logged, which is what makes it safe to paste a live token or a private packet capture. Each decoder also carries a plain-English explainer, a spec table and answers to the questions people actually ask about that format.
Nothing leaves the tab
Every decoder is pure client-side JavaScript. Paste a secret token or a private certificate — it is processed in memory and never uploaded.
Built like an instrument
Structured readouts, not just a blob of text. See the fields, the bytes, the checksums and the warnings that matter for each format.
One place for everything
Stop juggling a dozen single-purpose sites. From JWTs to VINs to packet headers, it is all on one consistent bench.
Nine categories of decoder
From everyday text encodings to certificates, packet headers, radio protocols and file formats — pick the bench that matches what you are holding.
Popular decoders
The formats people paste most often — each with a working decoder and a full explainer of how the format works.
Questions, answered
Paste it. Read it. Move on.
No sign-up, no upload, no tracking. Just open a bench and decode.
Explore all 90 tools