Effective date: August 16, 2026
ChemPal ("the extension") is a browser extension that lets you search and compare laboratory chemical product listings across supported supplier websites. This policy explains what data the extension handles, where it goes, and why.
Short version: ChemPal has no backend server of its own, shows no ads, and never sells your data. It does use PostHog, an independent product‑analytics service, to collect basic usage and error statistics — which searches are run, how many results they return, when the extension is installed or updated, and when it hits an error — associated only with a random, per‑install identifier, never your name or an account. Beyond that, the data that leaves your browser is the search terms and chemical identifiers you enter, sent directly to the third‑party supplier and public chemistry services you choose to search — the same way your browser would send them if you visited those sites yourself.
ChemPal is an independent, open‑source project maintained by Justin Hyland. There is no company, hosted service, or third‑party data processor operated by the developer.
When you run a search, the extension sends your query — a product name, CAS number, chemical formula, or similar identifier — directly to the supplier websites and public chemistry services you have enabled, in order to retrieve and display matching product listings and pricing.
Because these are ordinary web requests, the receiving third party also sees the standard technical information any website receives (such as your IP address and browser user‑agent). ChemPal does not add any identifier of its own to these requests. The developer does not receive, log, or store your searches.
Some suppliers require an active session to return search results. For those suppliers, the extension reads and sets cookies on that supplier's own domain solely to establish the session needed to perform your search. These cookies are used only for the supplier's normal site functionality; the extension does not use cookies to profile or track you, and does not share cookie data with the developer or any unrelated party.
The extension stores the following locally on your device (via the browser's extension storage and IndexedDB). This data never leaves your browser and is not transmitted to the developer:
If you save a product as a favorite, the extension may create and use a bookmarks folder (e.g. "ChemPal Favorites") in your browser to store it. The extension accesses your bookmarks only to provide this feature and does not read or transmit your other bookmarks to any external party.
The extension reads limited information about your current browser tab (such as the page URL) to provide context for opening product pages, search selections, and related links. This information is used only at the moment you take an action and is not logged or transmitted to the developer.
ChemPal uses PostHog, an independent product‑analytics service, to understand how the extension is used, so the developer can prioritize fixes and improvements. It sends an event to PostHog when you:
These events are associated with a random identifier generated and stored on your device, not with your name, email, or any account, and the extension loads no advertising or third‑party tracking code. Every event is sent as an anonymous event, meaning PostHog does not build or update a person profile for you — there is no stored record that accumulates properties over time. As with any web request, PostHog also receives standard technical information such as your IP address, from which it derives an approximate country or region, and which it processes under its own privacy policy. ChemPal does not use this data for advertising or to profile you.
If you use the Report a bug or Report Error actions, ChemPal opens a prefilled GitHub issue or Google Form in a new browser tab. The prefill includes diagnostic details — such as the extension version, your browser and operating system, and recent error messages captured on your device — to help diagnose the problem. Nothing is submitted automatically: the report opens for you to review and edit, you send it under your own GitHub or Google account, and you can remove anything first or simply close the tab.
Depending on which suppliers you enable and which features you use, the extension may send requests to:
pubchem.ncbi.nlm.nih.gov) and the CACTUS chemical resolver
(cactus.nci.nih.gov) — to resolve chemical names, CAS numbers, and formulas.
Only the chemical identifier you are looking up is sent.api.github.com) — to check whether a newer version of the
extension is available. No personal data is sent.us.i.posthog.com) — to collect the usage and
error statistics described in section 2.6, tied only to a random identifier.Each of these third parties handles the data it receives under its own privacy policy. ChemPal has no control over, and takes no responsibility for, the data practices of these independent services.
| Permission | Why the extension requests it |
|---|---|
storage |
Save your settings, favorites, and search/price history locally. |
cookies |
Establish the session cookies certain suppliers require to return search results, on those suppliers' own domains. |
bookmarks |
Create and manage the favorites folder used to save products. |
tabs |
Read the current tab's context to open product pages and search links, and to power the right‑click "search selection" action. |
contextMenus |
Add a right‑click menu item to search selected text with ChemPal. |
| Host permissions (supplier domains, PubChem, etc.) | Send search and lookup requests to the supplier and chemistry services you enable. |
All data the extension keeps is stored locally in your browser. You remain in control of it at all times:
Because the developer never receives your data, there is nothing for the developer to retain or delete on your behalf.
ChemPal is a tool intended for laboratory, educational, and professional use. It is not directed to children under 13 and does not knowingly collect any information from them.
This policy may be updated as the extension evolves. Material changes will be reflected by updating the effective date above and publishing the revised policy in the extension's repository. Continued use of the extension after an update constitutes acceptance of the revised policy.
Questions about this policy or the extension's data practices can be directed to:
Justin Hyland — jhyland87@gmail.com https://github.com/jhyland87/chem-pal