Most sales teams know the challenge: knowing which buyers are actively researching your solution is one thing—but turning those signals into actual meetings is another. That’s where LeadOnion and CallSine join forces.

What is LeadOnion?

LeadOnion is built to surface which companies and contacts are showing substantive behavior: researching topics, visiting web pages, showing intent signals across 20+ sources, and even identifying individuals behind anonymous traffic.

It combines account-level, person-level and website-visitor signals into one unified data layer—so you’re not just tracking companies, you’re tracking real buyers showing real interest.

That’s the kind of data that matters. And now, it’s data you can act on directly inside CallSine.

From Signal to Outreach in a Click

With CallSine’s new LeadOnion-powered Outreach Agent, you can deploy an Agent that takes LeadOnion’s rich prospect signals and turns them immediately into outreach-ready lists—without manual wrangling or guesswork.

Setup is straightforward:

• When creating an Outreach Agent in CallSine, choose Webhook as the lead source and select LeadOnion.

• Then go to your LeadOnion account and configure the integration according to their setup flow—pointing to the webhook/data feed URL that CallSine provides.

• From that point forward, the Agent handles the heavy lifting.

Your Outreach Agent will continuously receive new LeadOnion-driven leads, check them against your defined buyer-personas, validate email addresses and contact info, remove duplicates or existing contacts, and build clean outreach lists of qualified prospects—ready for action.

Why Filtering Still Matters

LeadOnion is world-class at identifying which buyers are active, what pages they visited, what topics they’re engaging with, and which contacts are tied to those behaviors.

But raw signals alone don’t guarantee outreach success. Not every contact fits your target persona, not every email is valid, and not every behavior warrants a campaign.

That’s the layer CallSine adds. We provide the intelligent filtering and qualification engine that ensures only the right prospects enter live campaigns—so your outreach is both scalable and sharply focused.

Less Time Sorting, More Time Selling

Instead of having your team spend hours digging through visitor logs, keyword spikes, and contact reveals, the LeadOnion-Agent setup automates that work. It runs in the background, makes filtering decisions automatically, and feeds your reps a steady stream of qualified leads. The net result: your team saves time, your pipeline flows faster.

Part of a Bigger Vision

The LeadOnion Agent isn’t a standalone novelty—it’s part of CallSine’s broader strategy of building specialized, source-specific Agents. As outlined in our recent Agent-Cluster vision post, the future of outbound sales isn’t one massive catch-all system trying to do everything. It’s a portfolio of experts—each Agent fluent in its own domain.
LeadOnion now sits on that bench. Other sources will follow.

The Takeaway

If you already have a LeadOnion account, you can begin building your LeadOnion-powered Outreach Agent today. With just a few clicks, you’ll be transforming high-precision buyer signals into booked meetings—without lifting a finger to sort, validate, or qualify manually.

This is the next wave of data-driven outreach: high-precision prospect discovery from LeadOnion, made actionable by CallSine.