Apollo.io is a business-to-business sales technology company based in San Francisco, California. Its platform combines a large database of business contacts with tools for finding prospects, reaching out to them, and tracking the results, and it is used by sales, marketing, and revenue teams to run their outbound programs. The company describes its category as go-to-market software, a label that covers the full path from identifying a potential customer to booking a meeting and closing a deal.
The company was founded in 2015 under the name ZenProspect and later rebranded as Apollo.io. It grew from a prospecting tool into a broader platform that pairs contact data with sales engagement features and, more recently, artificial intelligence. By the time of its 2023 financing, Apollo.io reported serving millions of sales professionals across hundreds of thousands of companies, and it has continued to add paying customers since.
What Apollo.io does
At its core, Apollo.io is built around a database of business contacts and companies. Sales teams search that database to build lists of potential buyers, filtering by attributes such as industry, company size, job title, location, and the technologies a company uses. The platform supplies contact details, including email addresses and phone numbers, so that representatives can reach the people who match their target profile.
On top of that data sits a layer of engagement tools. Users build multi-step outreach sequences that combine email, calls, and social messages, then track opens, replies, and meetings booked. The platform also includes a dialer for placing and recording calls and connects to customer relationship management systems so that activity stays in sync with a company's existing records. The combination of data and outreach in one product is what Apollo.io presents as its main advantage over using separate tools.
Founding and history
Apollo.io was started in 2015 by Tim Zheng, Ray Li, and Roy Chung, originally operating as ZenProspect. The founders set out to solve a problem they had seen firsthand, namely how much time sales teams spent finding accurate contact information and managing scattered outreach tools. The young company joined the Y Combinator accelerator in its Winter 2016 batch, an early milestone that connected it with mentors and investors.
The company later rebranded from ZenProspect to Apollo.io, a change that reflected its move from a narrow prospecting service toward a wider go-to-market platform. Over the following years it expanded its database, added engagement and analytics features, and built integrations with the major CRM systems that sales teams already relied on. You can read more about its co-founder in our profile of Tim Zheng.
Product and platform
Apollo.io organizes its product around a few connected areas. The contact and company database is the foundation, and the company has reported figures in the range of hundreds of millions of contacts and tens of millions of companies. Around that data, the prospecting tools let users define their ideal customer and pull matching lists, while enrichment features keep records current as roles and companies change.
The engagement side of the platform handles the outreach itself. Sequences automate a series of touches across channels, the dialer supports live calling, and reporting shows which messages and steps are producing replies and meetings. In recent years the company has added artificial intelligence features that help draft personalized messages and recommend next steps, positioning the assistant on top of its existing data. Apollo.io's products and pricing are described on its own site at apollo.io.
Who it is for and why it matters
Apollo.io is aimed primarily at outbound sales teams, from individual representatives at small startups to larger revenue organizations. Because it bundles data and outreach into a single subscription and offers a free tier, it has been adopted widely by smaller companies that want the kind of prospecting capability that was once reserved for firms with bigger budgets. The platform sits alongside other tools that founders and operators evaluate in our guide to the best AI tools for business.
The company's growth has tracked the broader shift toward consolidated go-to-market software, where buyers prefer one system over a stack of separate point tools. In August 2023, Apollo.io raised a 100 million dollar Series D round led by Bain Capital Ventures at a valuation of roughly 1.6 billion dollars, bringing its total funding to about 250 million dollars at the time. That financing, reported by outlets including TechCrunch, underlined its position as one of the more prominent companies in the sales technology market.
Frequently asked questions
What is Apollo.io?
Apollo.io is a business-to-business sales platform that combines a large contact and company database with prospecting, outreach, and analytics tools. Teams use it to find potential buyers, run multi-step email and call sequences, and track the results, all from one system.
When was Apollo.io founded and where is it based?
The company was founded in 2015, originally under the name ZenProspect, and is headquartered in San Francisco, California. It later rebranded as Apollo.io.
Who founded Apollo.io?
Apollo.io was co-founded by Tim Zheng, Ray Li, and Roy Chung. The company joined the Y Combinator accelerator in its Winter 2016 batch.
What does Apollo.io's platform include?
It includes a database of business contacts and companies, prospecting and list-building tools, data enrichment, multi-channel outreach sequences, a dialer, analytics, CRM integrations, and AI features that help draft messages and suggest next steps.
How much funding has Apollo.io raised?
In August 2023 the company raised a 100 million dollar Series D round led by Bain Capital Ventures at a valuation of about 1.6 billion dollars, bringing its total funding to roughly 250 million dollars at that time.