
Hem and Haw by Tin Le
ExperimentalExperimental
Looks for hashed email addresses (HEMs) and other personal information sent to third parties.
You'll need Firefox to use this extension
Extension Metadata
Screenshots




About this extension
https://tincangit.github.io/hemandhaw-study/
About Hem and Haw:
This browser extension monitors when hashes of your personally identifiable information (like emails or phone numbers) are sent to third parties.
How it works:
- You enter email addresses, phone numbers, and/or other details, and press submit.
- Hem and Haw creates hashes of these inputs.
- When a matching hash is detected being sent to a third party, Hem and Haw takes note and logs to our server:
Type of data (e.g., email),
Hash type (e.g., MD5),
Third party's hostname,
Originating website's hostname,
Where in the transmission (HTTP request) the hash was found,
Whether you use an ad blocker (based on your response).
At any point, you can stop Hem and Haw from searching for hashes, add/modify/delete the PII to search for, and see the logs of transmissions.
What Hem and Haw does NOT collect:
- Your actual personal data (e.g., email addresses or phone numbers),
- HTTP request details and data,
- Any other personal information. Your IP address is also not collected by our server.
IMPORTANT NOTE:
Hem and Haw will clear all results when you clear all history.
About Hem and Haw:
This browser extension monitors when hashes of your personally identifiable information (like emails or phone numbers) are sent to third parties.
How it works:
- You enter email addresses, phone numbers, and/or other details, and press submit.
- Hem and Haw creates hashes of these inputs.
- When a matching hash is detected being sent to a third party, Hem and Haw takes note and logs to our server:
Type of data (e.g., email),
Hash type (e.g., MD5),
Third party's hostname,
Originating website's hostname,
Where in the transmission (HTTP request) the hash was found,
Whether you use an ad blocker (based on your response).
At any point, you can stop Hem and Haw from searching for hashes, add/modify/delete the PII to search for, and see the logs of transmissions.
What Hem and Haw does NOT collect:
- Your actual personal data (e.g., email addresses or phone numbers),
- HTTP request details and data,
- Any other personal information. Your IP address is also not collected by our server.
IMPORTANT NOTE:
Hem and Haw will clear all results when you clear all history.
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Permissions and dataLearn more
Required permissions:
- Download files and read and modify the browser’s download history
- Access browsing history
- Access browser tabs
Optional permissions:
- Access your data for all web sites
More information
- Add-on Links
- Version
- 3.5.4
- Size
- 1,014.21 kB
- Last updated
- 2 days ago (4 Jul 2025)
- Related Categories
- Licence
- MIT Licence
- Privacy Policy
- Read the privacy policy for this add-on
- Version History
- Tags
Add to collection
Release notes for 3.5.4
- Searching for more phone variations
- New privacy-ranking use question
- Prolific heartbeat now also sends number of search items
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