If a company aims to incorporate in-app messaging or voice calling, it can leverage existing solutions like Twilio, rather than building its infrastructure from scratch. Likewise, for payment processing, Stripe is a go-to option; and for mapping needs, Google Maps is an industry leader.
However, integrating real-time multiplayer collaboration into software—similar to platforms like Google Docs or Figma—poses a unique challenge for developers. One route is to develop a custom solution and deploy it in the cloud, but this approach can be complex and resource-intensive. Alternatively, developers can utilize managed services like Pusher (owned by Twilio competitor MessageBird) or Atlassian-backed Liveblocks; while these options are popular, they can limit the flexibility developers need, as they often come with proprietary restrictions.
Enter PartyKit, an open-source deployment platform filled with essential libraries for companies looking to integrate multiplayer capabilities into their applications. “In the past, building and scaling collaborative backends required specialized expertise and significant operational investment,” said PartyKit founder and CEO Sunil Pai. “With PartyKit, it takes just minutes, making it accessible for most developers.”
After leaving his position as a senior systems engineer at Cloudflare last year, Pai launched an initial version of PartyKit alongside collaborative whiteboard app Tldraw. Since then, he has completely rewritten the product to accommodate a wider range of applications and successfully raised $2.5 million in pre-seed funding. This financing round was led by the prominent VC firm Sequoia Capital, with contributions from Cursor Capital, Remote First Capital, along with angel investors like Cloudflare co-founder Matthew Prince and Vercel co-founder Guillermo Rauch.
PartyKit is similar to services like Vercel or Netlify, but with a dedicated focus on collaboration. Developers can use their existing JavaScript or TypeScript code while integrating PartyKit with their chosen tools and services, enabling testing in their local environments through continuous integration and continuous delivery (CI/CD) practices.
“By offering powerful low-level building blocks for developers, PartyKit empowers them to create applications tailored to their needs, alleviating concerns about the underlying infrastructure complexities,” Pai explained.
In addition to enabling real-time collaboration between users—through digital whiteboards, games, or code-editing tools—companies can also integrate large language models (LLMs) from providers like OpenAI or even their proprietary models. This functionality allows human operators to collaborate alongside AI agents, with PartyKit managing background processes, memory, and context for these intelligent components—all with minimal coding effort.
For instance, a product design company might implement an AI assistant that offers suggestions during the website or app design process. Similarly, journalists could benefit from an embedded AI helper within their content management system (CMS) that provides real-time fact-checking and advice on tone and structure.
“Creating applications like these necessitates real-time infrastructure that delivers data and actions to users seamlessly,” Pai remarked. “With LLMs, collaboration extends beyond just humans—it includes AI entities contributing in various capacities. There’s a significant gap in existing platforms that empower developers to build such applications, which is why I founded PartyKit.”
On a technical level, PartyKit utilizes Cloudflare’s infrastructure, reflecting Pai's experience during his year-long tenure there. Prior to Cloudflare, he worked on multiplayer apps at Meta’s Oculus division, where low-latency and real-time capabilities are crucial for collaborative virtual reality experiences.
“In each of my roles, I was struck by the level of investment and effort needed on the infrastructure side to enable collaborative experiences,” Pai noted. “While application development has become increasingly accessible over the last two decades—recalling times when database expertise was mandatory to launch a blog—the same accessibility hasn’t reached multiplayer infrastructure. It isn’t surprising that creating platforms like Google Docs, Figma, or high-end games requires significant financial power.”
PartyKit has been in open beta since July, recently announcing its first hires. Today marks the formal introduction of its funding round and the launch of its platform for general use. The company is also primed to roll out premium features tailored for enterprise users, such as team management, analytics, and compliance. Pai emphasized that PartyKit would support both on-premise and cloud hosting, addressing the needs of enterprises facing strict regulatory requirements regarding data storage and processing.
“Our vision is to make real-time, multiplayer development accessible to millions of developers worldwide, and we believe the best way to achieve that is by offering it as a robust infrastructure solution,” concluded Pai.
Ranking
