Static + Browser-Only

Plain Text Regex Tester Online

Test regex rules against JSON online. Put regex rules JSON on the left, validate a plain text payload on the right, and highlight invalid or missing fields directly in the browser.

This is useful for plain text validation, support note review, and regex-based key-value checks without uploading data.

Rules

Regex rules JSON

Paste regex rules JSON on the left and a plain text payload on the right.

Payload

Payload Text

Validated payload with field-level regex highlights will appear here

What Is It

What is a plain text regex tester?

This page validates plain text against a rules JSON object where each field contains a regex pattern. It helps teams test whether key-value lines match expected formats before sharing, debugging, or using that text elsewhere.

Use Cases

When should you validate plain text with regex rules?

Check API fixtures before QA or release review
Validate form payload patterns like email, phone, and member IDs
Review line-based text against internal standards
Highlight plain text fields that break expected regex rules

Features

What this plain text regex validation tool can do

Use a JSON object of regex rules as the source of truth
Validate fields such as email and phone
Highlight invalid and missing values in plain text payloads
Run locally in the browser with no upload

FAQ

Common questions

How do I test a payload against regex rules?

Paste your regex rules JSON on the left, paste the matching payload format on the right, and run validation. Invalid or missing fields are highlighted in red inside the payload viewer.

Can I validate plain text fields?

Yes. Nested objects are supported, so rules like customer.memberId and customer.email work when the text structure matches.

Does this work only for plain text?

Yes. This page is focused on plain text validation. Other regex pages are available for XML, HTML, CSV / TSV, SQL, logs, plain text, and HTTP payloads.

Does this upload the rules or payload?

No. Validation runs locally in the browser and no rules JSON or payload content is uploaded during the workflow.

Why plain text regex validation matters before sharing or testing text

Teams often assume sample payloads are valid until a downstream system rejects them. A plain text regex tester makes those formatting problems visible before a payload reaches QA, support, docs, vendors, or AI workflows.

This is useful for text fields such as emails, phone numbers, IDs, and status values where format errors are easy to miss.

Teams often search for a free regex tester online when they need to validate field formats, check sample payloads, enforce naming rules, or catch invalid values before QA, release review, or external sharing. A browser-only regex validator is especially useful when payloads, logs, or request examples should stay local and should not be uploaded to a remote validator.

Examples

Example plain text rules and payload

The rules JSON defines regex patterns, and the payload is plain text with invalid values highlighted.

Regex rules JSONValidation rules

{
  "email": "^[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,}$",
  "phone": "^\\d{3}-\\d{3}-\\d{4}$",
  "status": "^(active|pending|paused)$",
  "customer": {
    "memberId": "^mem_\\d{3,}$"
  }
}

Payload TextInvalid fields highlighted

{
  "email": "john@example.com",
  "phone": "2045550199",
  "status": "trial",
  "customer": {
    "memberId": "204"
  }
}