Base64 in JSON

Client

Walk string values, try UTF-8 Base64 decoding where it looks plausible, and read short previews—nothing is uploaded.

Learn more: embedded Base64

Walk string fields, guess Base64-shaped payloads, and show UTF-8 text previews—useful for JWT-like blobs or embedded JSON without leaving the tab.

Heuristics

Detection is heuristic: short strings or non-text binary will not look useful. Pair with Encoding tools or the hex tool for strict byte views or file workflows.

Base64 string preview

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Walks string values, heuristically treats long base64-shaped strings as Base64, and decodes UTF-8 text for preview—use the hex encode/decode tool when you need a byte-accurate view outside this JSON walk.

Common use cases

  • Spot embedded Base64 in API responses and preview UTF-8 text without leaving the browser.
  • Quickly sanity-check whether a string field is likely binary payload versus plain text.
  • Pair with Encoding workspace tools when you need full decode/encode of arbitrary binary.

Common mistakes to avoid

  • Treating every decoded preview as correct

    Detection is heuristic. Random-looking text can still decode to garbage; verify with domain knowledge.

  • Confusing JWT segments with generic Base64

    JWT uses Base64URL and may need different handling—use the JWT decode tool when working with tokens.

FAQ

Is scanning performed on your servers?

No. String walks and decode attempts run locally in your tab.

Does this replace the Encoding or Hex tools?

Use this for quick JSON-embedded strings. For raw bytes, files, or non-UTF-8 data, switch to the dedicated encoding or hex workflows.

More tools

Related utilities you can open in another tab—mostly client-side.