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Built for Teams Shipping Production-Grade AI Chat

Over the past 12 months, tens of thousands of developers have built and deployed industry-leading AI chat experiences using our frontier language models. Along the way, we learned a hard truth: even the most advanced teams struggle to build reliable, high-quality AI chat systems with today’s tools.

AI chat is deceptively complex. It must deliver fast, natural conversations, handle deep reasoning, maintain context over long sessions, and scale across millions of interactions. Teams repeatedly face the same problems—better reasoning increases latency, small prompt changes cause unpredictable behavior, and fragile multi-provider infrastructure makes production scaling painful.

Line is built for that reality. With the Line SDK, developers can design intelligent chat agents entirely in code—combining prompts, logic, memory, tools, and background reasoning without constraints. Handle edge cases directly, integrate your favorite libraries, and customize every interaction with full control.

That’s why we built Line—a modern AI chat development platform that helps developers and businesses build best-in-class conversational AI, faster.

Iterate Faster with Line

Building great AI chat agents is an iterative process. You make changes, test them in real conversations, learn from results, and improve continuously. Line is built to speed up that loop

Get from idea to your first AI chat agent in minutes—starting from a prompt or template. Develop locally, deploy with a single command, and start chatting instantly. Share agents with teammates or stakeholders in seconds.

Line automatically records conversations, stores transcripts, tracks latency and system metrics, and provides detailed logs for debugging and auditing. Built-in evaluations and custom LLM-as-a-judge scoring let you measure performance over time—across quality, accuracy, task success, and user satisfaction.

Frontier Models, Fully Integrated Infrastructure

High-quality AI chat requires frontier-grade language models and reliable infrastructure. Our research team builds and deploys state-of-the-art models designed for fast, accurate, and context-aware conversations.

By deeply integrating models and infrastructure, Line delivers lower latency, higher reliability, and more consistent outputs. Every chat agent runs on our globally distributed platform, scaling seamlessly from a handful of users to millions of conversations.

For enterprise teams, Line supports on-prem deployments, private infrastructure, and model customization through fine-tuning—ensuring performance, privacy, and compliance at scale.

Line Is Available Today

Line is available now for all developers. As part of the launch, every subscription tier includes monthly platform credits applied directly to agent usage—at no additional cost.

Our north star is simple: no matter how complex your logic, every AI chat interaction deployed on Line should feel fast, natural, and reliable.

With Line, we’re making frontier AI chat accessible to every developer—and making intelligent conversations accessible to the world.