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FeuTex · free tools runs in-browser no bloat built by LiMiT

Validator Toolkit

Validate common data formats in one place. Paste one value or a whole list, choose a validator (or auto-detect), and get clean, copyable results—fully client-side.

Category: General · URL: /tools/validator-toolkit.html
Privacy: runs locally in your browser. No uploads, no tracking scripts.

How to use

Paste your values, pick a validator (or leave it on Auto), then validate.

  1. Choose Mode: Auto-detect or a specific type.
  2. Paste input (one per line for batch checks).
  3. Click Validate to get a compact report.
  4. Switch Output to JSON if you need machine-readable results.
Keywords this page targets (natural cluster): validator toolkit, batch validator online, auto detect validator, email validator, url validator, ip address validator, ipv6 validator, json validator, uuid validator, iban validator, jwt format validator, base64 validator, hex string validator, domain validator, offline validator tool, validate list of inputs, client side validation tool, quick data validation, regex free url validation, validate uuid v4, validate iban checksum, validate json syntax
Secondary intents covered: Validate many lines at once and count how many are valid, Auto-detect what type an input looks like (email/uuid/json/etc.), Check if a string is valid JSON without sending it anywhere, Verify an IBAN checksum locally before submitting a form, Spot malformed URLs/IPs before logging or parsing them, Generate copyable results (text or JSON) for debugging, Quickly validate JWT structure and decode header/payload (no signature verification), Validate Base64/Base64URL strings before decoding

FAQ

What does “Auto-detect” do?

It runs several validators locally and reports which formats match your input (for example: uuid, json, iban).

Is this tool offline and private?

Yes. Validation runs in your browser and nothing is sent to a server.

Can I validate a list of values at once?

Yes—keep “Batch (1/line)” enabled and paste one value per line.

Does the email validator check if an address really exists?

No. It only checks syntax (format), not mailbox/domain deliverability.

What IBAN checks are performed?

It checks the basic pattern and validates the checksum using the standard MOD 97 algorithm.

Does the JWT check verify the signature?

No. It validates the 3-part structure and decodes header/payload when possible, but it does not verify signatures.

Why can Auto-detect show multiple matches?

Some strings can be valid in more than one format (for example, a short hex string may also look like Base64). Use a specific mode when you need a single strict check.