Conclusion: Compare environmental differences by matching numbers and settings
Use the tool to check browser, version, OS, device candidates, screen, viewport, DPR, language, cookies, User-Agent, and more; enable safe sharing mode; then choose a format from text, Markdown, and JSON. Add the actions taken and errors separately.
| Item | worth seeing | Precautions when making decisions |
|---|---|---|
| Environment | Browser, version, OS, and device candidates | Includes the decision value |
| Display | Screen, Viewport, DPR | Important for reproducing display corruption |
| Settings | Language, Cookie, Touch, TimeZone | Share only what is necessary for the issue. |
| Copy | Text / Markdown / JSON | Safe sharing mode and content review |
| Reproduction | URL, date and time, action, expected and actual results | Add it outside the tool |
Distinguish between acquired values, judgment values, and reference values
A web page can inspect only the information exposed by the browser. Do not treat current screen or viewport values as having the same confidence as OS or device candidates inferred from a User-Agent.
| Type of information | Typical example | How to handle |
|---|---|---|
| Obtained directly from browser API | Screen, Viewport, DPR, language, cookie availability, number of touches, etc. | This is the value exposed by the current browser and is not the complete specification of the device. |
| Determined from User-Agent etc. | Browser name/version candidates, OS name/version candidates, rendering engine | Treated as a judgment value because it may be changed, reduced, or falsified. |
| Approximate/reference value | Estimated memory, number of logical processors, GPU, storage space, etc. | It may not necessarily match the actual loading capacity, product name, and quota limit. |
| Not available | Exact product model number, CPU product name, MAC address, serial number, etc. | Allow Unknown and do not force completion from another value |
Leave the judgment result as an estimate, such as "Device type: Estimated to be a smartphone." This information does not 100% identify the exact model name or PC specifications.
Steps for pasting into an inquiry
Browser:
Browser Version:
OS:
Device (including inferred values):
Screen:
Viewport:
DPR:
Language:
Cookie:
User-Agent (only if needed):
Date and time of occurrence:
Steps to reproduce:
Error details:When you enable "Safe sharing mode" in the device information tool, sharing of the user agent, detailed screen dimensions, model, estimated memory, GPU, and similar information is reduced. Add them only when needed, and reread the copied text.
Range that can be confirmed with the device/browser information confirmation tool
| classification | Main display | nature of information |
|---|---|---|
| Browser/OS | Browser, version, engine, OS, OS version, User-Agent, etc. | Mainly determined from User-Agent and Client Hints |
| Screen/display | Screen, available screen, Viewport, outer frame, DPR, orientation, display settings | Obtained from browser API |
| Input/region settings | Language, locale, TimeZone, cookie availability, maximum number of simultaneous touches | Obtained from browser API |
| Reference information | Number of logical processors, estimated memory, GPU, storage area, Web API support | May be unsupported/not disclosed/estimated |
| share | Secure sharing mode, bulk copy of text, Markdown, and JSON | Read content before sharing |
The tool organizes the values that can be retrieved by the displayed browser in the browser. Enabling secure sharing mode will limit the scope of sharing of User-Agent, detailed screen dimensions, device model, estimated memory, GPU, etc.
Information can be found on this page. When pasting it into an inquiry, please make sure that other personal information such as service name, account name, URL, and operation details are not mixed in.
Perform additional checks in the browser UI and developer tools
- Refresh information in the browser where the problem occurs.
- Enable safe sharing mode
- Copy the format appropriate for the contact channel from text, Markdown, or JSON
- Add the occurrence date and time, target URL, reproduction steps, and error details.
The cause cannot be determined from the device information alone. Reproduce with the same URL, same operations, and same account conditions to isolate Console errors, network failures, CSS application status, and effects of extensions and content blockers.
Isolation if the problem persists
- Check whether the copied result requires the User-Agent or detailed values
- Do not include cookie values, authentication information, personal information, or internal URLs
- Do not report reference values as exact PC specifications
Compare only one condition at a time, such as normal window and private window, normal browser and in-app browser, Wi-Fi and mobile connection. Even if the obtained result is unknown, it can be used as investigation material if you leave the found value and reproduction steps.
Share device information only to the extent needed for debugging or support. Do not design systems that store every available value by default for fingerprinting or tracking.
Browser specifications confirmed in this article
The public scope of browser API and User-Agent will change. The article uses MDN and browser official materials as a basis, and does not supplement information that cannot be obtained or reduced values with other guesses.
| Official materials | Points confirmed in the article |
|---|---|
| MDN Screen.width / Window.innerWidth | Screen size and layout viewport are different values, and both should be handled in CSS pixel units. |
| MDN Window.devicePixelRatio | Ratio of physical pixels to CSS pixels, which may be affected by page zoom |
| MDN Navigator.language / languages | Must be a list of preferred and ordered languages exposed by the browser |
| MDN Navigator.cookieEnabled / maxTouchPoints | Do not overinterpret the availability of cookies and do not equate the number of touches with the type of device. |
| MDN UA sniffing / Chrome UA Client Hints | Prioritize Feature Detection for function determination and do not rely only on reduced UA |
Example: report a layout issue in a GitHub issue
Copy the result in Markdown-formatted safe sharing mode, then paste the browser, OS, viewport, and DPR into the issue.
Add reproduction steps, expected results, actual results, and a minimal screenshot, and confirm there are no account names, internal URLs, cookies, or similar information.
- Update environment information in the issue tab
- Copy Markdown in safe sharing mode
- Add reproduction steps and expected/actual results
- Check secret information before posting an issue.
Copying everything is the starting point of an investigation. Remove unnecessary items and share only the information needed to reproduce the issue.
Frequently asked questions
- What is excluded in safe sharing mode?
- The current implementation excludes private-designated fields such as User-Agent, platform, architecture, model, detailed screen dimensions, estimated memory, GPU, and storage from shared content.
- Can I make an inquiry based only on the tool results?
- In addition to environment values, include the occurrence date and time, target URL, steps, expected result, actual result, and error details.
Try It in Your Browser
Your input is processed entirely in your browser. Keep the original data, review the output, and only then save or share it.
Check device/browser information