See what bidirectional isolation does, by comparing your mixed text without isolation and with each foreign run wrapped in an isolate.
Quick Answer
The Urdu RTL Isolation Tester shows the effect of isolation on mixed text. It displays your text as it is, then again with each English or number run wrapped in a first-strong isolate, so you can see how isolation keeps a foreign run from disturbing the Urdu around it. Everything runs in your browser.
Test Bidi Isolation
Paste mixed Urdu and English text to see isolation at work.
Isolation result
- Runs isolated
- 0
- Isolates present
- 0
- RTL characters
- 0
- Foreign characters
- 0
Without isolation (dir=rtl)
With isolation applied (dir=rtl)
Rate This Tool
Tap a star to rate the Urdu RTL Isolation Tester.
What the Urdu RTL Isolation Tester Does
The Urdu RTL Isolation Tester shows what bidirectional isolation does to mixed text. It displays your text without any isolation, then again with each English word or number run wrapped in an isolate, so you can compare the two and see how isolation protects the Urdu flow.
Isolation is the modern, recommended way to embed a foreign run, and this tool makes its effect visible.
Everything runs on your own device. Your text is never uploaded or stored, so it stays private while you test it.
How to Test Isolation
- Paste your text. Enter Urdu with English words or numbers inside it.
- Compare the previews. See the text without isolation and with isolation applied.
- Read the counts. See how many runs were isolated and how many isolates were already there.
- Copy or download. Copy the report, or save it as a text file.
What an Isolate Does
An isolate wraps a run of text so that its direction is worked out on its own and does not affect the text around it. Without an isolate, a number or an English phrase can pull neighbouring punctuation the wrong way. With one, the run is kept separate and the Urdu stays put.
Comparing the Two Previews
The first preview shows your text as it is. The second shows it with each foreign run wrapped in an isolate. When the two look the same, the text did not need isolation. When they differ, isolation has fixed the order of something at a boundary.
The First-Strong Isolate
The tool uses the first-strong isolate, which takes its direction from the first strong character inside the run and closes with the pop isolate. It is the safe default, since it works whether the run is English, a number, or a mix, without you having to choose a direction.
A Worked Example
Text:
Loading example…
Isolation result:
Loading example…
The live tester is preparing this example…
The result above comes from the same function the tool uses, so it reflects real behavior. Press Load Example to try it.
Who Uses This Tester
Developers use it to decide where to add isolates. Localization engineers use it for message templates. Anyone embedding English in Urdu uses it to see the effect.
Accuracy and Limits
The tool wraps runs of left-to-right and number characters in a first-strong isolate and shows the result in a real right-to-left preview. It marks the boundaries of a run at the neutral characters. It shows isolation, not the full Bidirectional Algorithm.
Good to know: to see the isolate characters themselves, use the bidi control character inspector.
Your Data Stays Private
The tester runs fully in your browser with standard web technology. Your text is not uploaded or stored, and it is not sent to any analytics service. Only your star rating is sent, to record the tool’s rating. When you close the page, your text is gone.
Frequently Asked Questions
What does the Urdu RTL Isolation Tester do?
It shows your text without isolation and with each foreign run wrapped in an isolate, so you can compare the two and see how isolation protects the Urdu flow.
What is an isolate?
A wrapper that works out a run’s direction on its own so it does not affect the text around it. It keeps a foreign run separate.
Which isolate does it use?
The first-strong isolate, which takes its direction from the first strong character inside the run and closes with the pop isolate.
When do the two previews differ?
When isolation fixes the order of something at a boundary, usually a number or an English phrase between two pieces of Urdu.
How do I see the isolate characters?
Use the bidi control character inspector, which lists the isolate and pop characters.
Is my data safe?
Yes. Everything runs in your browser. Your text is never uploaded, saved, or shared.
Is this tool free?
Yes, it is completely free and needs no account to use.
Does it work on mobile?
Yes. It works on phones, tablets, and computers.
Explore More Free Urdu Unicode and RTL Tools
Inspectors, detectors, cleaners, and normalizers built for real Urdu Unicode text.
Open the Urdu Tools hubSources and standards
- The Unicode Standard and code charts (Arabic block U+0600, Arabic Supplement, Presentation Forms). unicode.org/charts
- UAX #9, Unicode Bidirectional Algorithm (RTL, marks, isolates, overrides). unicode.org/reports/tr9
- UAX #15, Unicode Normalization Forms (NFC, NFD, NFKC, NFKD). unicode.org/reports/tr15
- MDN Web Docs, String.prototype.normalize and code point methods. developer.mozilla.org
This free tool wraps runs of left-to-right and number characters in a first-strong isolate and shows the result in a right-to-left preview. It marks run boundaries at neutral characters and shows isolation, not the full Bidirectional Algorithm. Your star rating is stored on the site.