Grammarly has entered an agreement to acquire Superhuman, a San Francisco-based email productivity startup, as part of its broader strategy to develop an artificial intelligence-powered productivity suite.

The two companies, both headquartered in San Francisco, declined to disclose the financial details of the deal. Superhuman, which became known for its exclusive, waitlist-based access model, was last valued at $825 million in 2021 and currently generates about $35 million in annual revenue.

The acquisition follows Grammarly’s recent $1 billion funding round led by General Catalyst, positioning the company to expand beyond its core grammar-checking tool. Grammarly, founded in 2009, now serves over 40 million daily users and reports annual revenue exceeding $700 million. The company is reportedly considering a rebrand as it broadens its product scope.

Superhuman, which has raised more than $110 million from investors including IVP and Andreessen Horowitz, markets itself as a fast and efficient email platform that uses AI to enhance productivity. The company claims its users send and reply to 72% more emails per hour compared to traditional platforms. Use of its AI-powered email composition tools has grown fivefold over the past year, though the platform faces competition from major players like Google and Microsoft, which are increasingly embedding AI features in their email clients.

“Email continues to be the dominant communication tool for the world,” said Grammarly CEO Shishir Mehrotra.

“Professionals spend something like three hours a day in their inboxes. It’s by far the most used work app, foundational to any productivity suite. Superhuman is the obvious leading innovator in the space.”

Mehrotra, who co-founded the collaborative document platform Coda—which Grammarly acquired last year—said that integrating email into Grammarly’s AI ecosystem was a natural progression. That acquisition provided the company with the infrastructure to develop AI agents that help users perform research, analysis, and team collaboration.

Superhuman CEO Rahul Vohra, along with more than 100 employees, will join Grammarly as part of the acquisition. While Superhuman will continue operating under its own brand, Grammarly plans to integrate its AI tools into the platform.

“The Superhuman product, team, and brand will continue,” said Mehrotra. “It’s a very well-used product by tens of thousands of people, and we want to see them continue to make progress.”

Vohra said the deal would allow Superhuman to access “significantly greater resources” and accelerate development in areas such as calendars, task management, and collaborative tools.

Both companies aim to create a network of AI agents capable of pulling information from emails, documents, and other workflows to automate routine tasks and improve response efficiency. This move places Grammarly in direct competition with larger tech firms such as Salesforce and other AI-focused startups now offering similar productivity solutions.