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Overview

The MoltSets Firefox Extension puts MoltSets enrichment in the Firefox sidebar next to LinkedIn. Open a profile, click a lookup, and get verified contact data from the MoltSets database in seconds. It’s built for salespeople, recruiters, and founders who already prospect on LinkedIn and want accurate contact details without copying, pasting, or switching tabs.

Coming soon to Firefox Add-ons

The MoltSets Firefox Extension isn’t available to install yet. In the meantime, use the Chrome Extension.
The extension doesn’t scrape LinkedIn. It reads only the URL of the profile in your active tab, then looks that URL up in the MoltSets database using the MoltSets API.

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What you get

Not sure which to pick? Start with the full business profile. Every email comes with an A–F risk score that rates how safe the mailbox is to send to. See Email risk scores for what each grade means.
Mobile lookups need a paid plan with a phone token subscription. One phone token is used per number found. See Getting carrier-verified mobile phones.

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Requirements

  • Firefox 140 or later
  • A MoltSets account and API key. Sign up for free to start with 1,000 API calls.

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Setup

1

Install the extension

Install MoltSets from Firefox Add-ons once it’s available. Firefox asks you to allow access to linkedin.com and api.moltsets.com when you install. The extension only reads the address of your LinkedIn tab. Nothing on the page is read or changed.
2

Open the sidebar

Click the MoltSets icon in your Firefox toolbar to open the sidebar.
3

Connect your API key

Click I already have an account, paste your API key, and click Connect. MoltSets keys start with ms_. Find or create a key in the MoltSets app. See Authentication for details.New to MoltSets? Click Sign up for free instead.

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Enrich a profile

1

Open a LinkedIn profile

Navigate to any personal LinkedIn profile. The sidebar recognizes the profile from the page address.
2

Choose a lookup

Click Get next to the data you need: full business profile, business email, personal email, or mobile phone.
3

Use the results

Results appear in the sidebar in seconds. Click an email or phone number to copy it.
The sidebar stays open as you move between profiles, so you can work through a list without reopening anything. New users see a Getting started checklist that ticks itself off as you open and enrich your first profile. Click the ? icon in the footer at any time to open the in-panel guide.

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Control what you spend

  • Nothing runs automatically. Every lookup starts with your click.
  • Lookups that find nothing are free. No tokens are charged for a not_found result.
  • Saved results don’t cost again. Results are saved in your browser. Return to a profile you’ve already enriched and your data is waiting. Click the refresh icon when you want the latest data.

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Track your usage

Your usage appears at the top of the panel:
  • Free plan: the number of free tokens remaining. Each lookup that finds something uses 1 token.
  • Paid plans: your fair use for the last 5 hours and the last week (5h records, 1w records, 5h requests). See the Fair Use Policy and Rate limits.
Click your account name in the footer to open the Account panel. It shows your plan, phone token balance, and when your limits reset. It updates as you browse, so an upgrade shows up straight away.

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Enriched contacts

Every profile you enrich lands in your Enriched contacts list, most recent first, with what was found for each person.
  • Search by name, company, or email.
  • Download a single profile from its page, or your whole list from the list view, as a CSV file.
  • Delete profiles one at a time, or select several and delete them in bulk.
The enriched contacts list reads from your browser only. Opening it never calls the API.

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CSV export

CSV files open cleanly in Excel and Google Sheets and are ready to import into your CRM. Each file has one row per profile with these columns: List fields such as skills and interests are joined with ; .

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Privacy and permissions

  • Reads only the URL. The extension reads the address of your active LinkedIn tab so it knows which profile you’re viewing. It doesn’t read page content or add anything to LinkedIn pages.
  • Sends data only when you click. A lookup sends the profile URL and your API key to api.moltsets.com. Nothing is sent until you click.
  • Stores data locally. Your API key and saved results stay in your browser’s local extension storage. They aren’t synced to other devices or to your MoltSets account.
  • No tracking. The extension contains no analytics or advertising code.
Permissions the extension requests:

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Remove your data

  • Click the sign-out icon in the footer to delete your API key from the browser. Saved lookups remain until you delete them.
  • Delete saved lookups for one profile, selected profiles, or all profiles from the Enriched contacts list.
  • Remove the extension from Firefox to delete everything it has stored.
See the MoltSets Privacy Policy for full details.
You’re responsible for using contact data in line with the laws that apply to you, such as GDPR, CAN-SPAM, CASL, and the TCPA. Mobile numbers aren’t screened against Do Not Call registries, so check them before you call or text.

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Troubleshooting

Make sure you’re on a personal LinkedIn profile page and that the extension has access to linkedin.com in Firefox’s add-on settings. Company pages, search results, and the feed aren’t profiles.
Mobile lookups need a paid plan and a phone token subscription. Click View plans in the panel or see pricing.
Upgrade to a paid plan from the MoltSets billing page to keep looking people up.
Click Report a problem at the bottom of the profile view, or email support@moltsets.com.

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Go further with the API

The extension enriches one profile at a time. To enrich whole lists, search for people and companies, or connect tools like Claude, ChatGPT, and Clay, use the MoltSets API, the MoltSets MCP server, or the Clay integration.
LinkedIn is a trademark of LinkedIn Corporation. MoltSets is not affiliated with, endorsed by, or sponsored by LinkedIn.