Customer service is one of the biggest areas of enterprise spending that AI can directly automate.

Large companies still employ thousands of people to answer calls, reply to messages, verify customers, look up information, update accounts, process requests, and solve fairly repetitive problems.

So far, most of this work has been hard to automate because customer conversations are unpredictable. Traditional chatbots and phone systems could follow predefined decision trees, but they struggled as soon as a customer asked something outside the script.

AI models can now understand natural language, keep track of context throughout a conversation, search company knowledge, access customer data, and generate increasingly human-like responses. And instead of just answering questions, an AI agent can authenticate a customer, access backend systems, check an account, update information, run workflows, and complete the request without needing a human employee.

That’s why customer service is one of the best real-world applications for AI agents, and this is exactly what Five9 does.

Five9 originally built its business around cloud contact center software. Its platform handles the infrastructure companies use to communicate with customers across voice and digital channels, including routing calls, managing agents, recording interactions, workforce management, analytics, and integrations with systems like CRM software.

Five9 already serves more than 3,000 customers and works with more than 1,400 partners globally. This allows Five9 to introduce AI directly into the contact centers companies already use.

Five9's Voice AI Agents can understand what a customer wants, work through the request, and take actions across enterprise systems. An orchestrator agent decides what needs to happen, while specialized agents can handle tasks such as identity verification, retrieving information from backend systems, and carrying out actions. If the AI cannot complete the request, the conversation can be transferred to a human agent while keeping the full context.

For the interactions that still require humans, Five9 is using AI to make those employees more productive. Agent Assist can transcribe calls, surface relevant information, provide real-time guidance, and automatically generate summaries after a conversation. Five9 also offers AI Knowledge, conversational analytics, workflow automation, and tools for managing these AI systems.

Five9 generated $312M of revenue in Q2 2026, up 10% year over year, while subscription revenue grew 14%. More importantly, AI revenue grew 78% year over year to approximately $39M during the quarter. That puts AI above a $150M annualized revenue run rate and means AI already represents around 15% of subscription revenue, compared with roughly 9% a year earlier.

The company is also starting to win much larger enterprise deployments. During Q2, Five9 announced a new customer agreement worth approximately $100M in total contract value through Google Cloud Marketplace.

Five9 has historically grown faster than its profitability suggested, but the company is now starting to show meaningful operating leverage. Q1 adjusted EBITDA reached $74.5M, or a 24.4% margin, compared with 18.8% one year earlier. Q2 adjusted EBITDA remained strong at $70.1M, or 22.4% of revenue, even as the company continued investing heavily to speed up AI implementations.

Five9 was one of the companies that benefited heavily during COVID, similar to Zoom. Its stock peaked during that period and then fell more than 90% from the highs at its lowest point, even though the business continued to grow. Now, it looks like it may have finally found a bottom which is driven by the new acceleration thanks to AI.