Introducing Agent 4 — our fastest, most versatile Agent yet. It's built around a simple idea: you should spend your time creating, not coordinating. Agent 4 takes on the tedious-but-necessary work in the background so you can stay in creative flow and ship production-ready software 10x faster. Because Replit is where software is built, run, and shipped — all in one place — Agent 4 can handle both the complex and the mundane, so you can focus on what's uniquely human: creativity.
Summary
Agent 4 is built on four pillars designed to keep you in creative flow and ship production-ready apps 10X faster.
- Design Freely: Generate design variants on an infinite canvas, tweak them visually, and apply the best one directly in your app.
- Move Faster: Tackle auth, database, back-end functionality and front-end design all at once with parallel agents, with progress across tasks clearly visible. Once done, tasks can be merged seamlessly into the main app.
- Ship Anything: Create mobile and web apps, landing pages, decks, videos and more in the same project, with shared context and design so you can scale efficiently.
- Build Together: You and your team can focus on planning your app while the Agent handles all the messy coordination and execution. Submit requests in any order, and Agent 4 intelligently sequences them and executes in the best order.
With Agent 3, we pushed autonomy forward. Agent could run for hours independently- self-testing, fixing issues, and driving builds ahead on its own. At the time, it set a new bar for autonomous vibe-coding agents and showed what was possible when software could move without constant oversight.
That breakthrough unlocked something important: once the mechanics of building can run independently, the next frontier is creative control.
With Agent 4, we’re building on that foundation by putting human creativity at the center of the process.
Agent 4
Agent 4 is built on four pillars designed to keep you in creative flow: tighter iteration loops, less context switching, fewer mundane tasks, and more progress per minute.
What makes this possible is that it's the complete environment where software is built, run, and shipped. That full-stack context allows Agent 4 to handle both the complex and the tedious, so you can focus on what’s uniquely human: creativity.
Let’s walk through the ecosystem of improvements that bring this to life.
Replit Agent 4 is incredible. Its ability to take a one-shot prompt and flesh out the requirements before a full build is unmatched. It requires very little guidance to take a rough concept to a functional prototype. This makes my life as a Product Manager 10x easier. Rather than writing requirements and waiting for Figmas, I can show, not tell.
— Alex Meyers, Principal Product Manager, Gusto
1. Design & build in the same place, anytime
Design iteration is the most frequent kind of change—and often the slowest. In many teams today, design and development happen in different environments. That separation can sometimes create extra coordination overhead, especially when small visual changes need to be reflected across both design and code.
With Agent 4, we’re dramatically speeding up design iteration by removing that friction. Design and code now live in the same environment. You can explore ideas, generate variants, and refine details inside your design board—without disrupting your working app or breaking your flow.
When you land on a design that works, you can bring that into your app and integrate them into production code. You can explore freely while it builds in the background, then move forward with confidence.
The result is faster iteration, fewer surprises, and designs that don’t just look good in isolation—they translate cleanly into the real product.
To make that possible, Agent 4 introduces a set of focused improvements:
1. Design while the Agent builds
You can now work on one part of your app while the Agent builds another. Design is no longer a separate mode, it’s something you can do continuously, at any point in the build process.
2. Faster design exploration with an infinite canvas & multiple UI variants
Sometimes you don’t want the answer—you want options that you can compare, refine the strongest one, and move forward. Agent 4 introduces a canvas that allows free-form design exploration and lightweight flows for generating and managing UI variants directly in context, so you can explore and iterate on real UI without leaving your app.
3. More precise and reliable design controls
We are providing more precise design controls like multi-select, hover/active state editing, responsive overrides, hover-to-preview interactions and easy undo etc. to enable you to make much more precise design changes directly in the UI, and those changes are applied straight to production code.
Agent 4 unlocks true collaboration and real-time learning — now our teams can design and build with our closest partners live, turn instant feedback into measurable wins, and deliver outcomes that delight customers and partners.
— Doug Rodermund, Principal Program Manager, Zillow
2. Do more at once
At some point, the only way to free up more time for strategic and creative work is to go faster on execution. Projects often feel slow because everything happens one step at a time. You wait for one thing to finish before starting the next, even when the work could move in parallel.
Agent 4 frees up more time for creativity by enabling parallel work—multiple agents working at the same time, each focused on a different part of the project. It’s the difference between one person tackling a checklist alone and a small team dividing the work and moving together.
There are two ways Agent 4 speeds things up:
- Working on multiple tasks in parallel. Independent tasks can run in parallel, with progress visible and coordinated. Once the tasks are done, they can be merged into the main project. When changes conflict, Agent 4 uses specialized sub-agents to resolve them.
- Breaking up big tasks automatically. For larger jobs, Agent 4 can split a single task into smaller pieces, work on them simultaneously with sub-agents, and recombine the results—shortening long-running tasks without sacrificing quality.
Because Replit powers your full environment—projects, files, and execution—it can coordinate this work safely. The result is faster iteration, less waiting, and more momentum, without losing control of your project. That’s performance you can feel.
Note: Parallel task execution will be available to Pro and Enterprise users, designed for power users who want to take full advantage of Agent 4’s advanced capabilities.
To celebrate the launch of Agent 4, we’re making it temporarily available to Core users for a limited time.
The parallel task execution is a game-changer for us. We have multiple builders working on the same codebase every day, and the ability to submit tasks simultaneously with full visibility before anything merges is exactly how we've wanted to work. Agent 4 feels like it finally matches the speed our team actually operates at.
— Barak Hirchson, Co-Founder & Chief AI Officer (CAIO), Payouts.com
3. Focus on the vision while Agent handles the execution
One of the biggest reasons building with an Agent can break your flow is the coordination overhead. When everything runs through a linear chat thread, you can end up spending more time managing the process than actually moving the project forward.
Agent 4 reimagines collaboration to work more like a great team: clear priorities, visible progress, parallel execution, and clean handoffs.
That’s why we’re introducing a task-based workflow. Team members can send multiple design or build requests at the same time and every request to Agent 4 is broken into discrete tasks that run in parallel in the background. You can track the status of each task, review the results, and approve them before they’re merged into your main project. Agent 4 intelligently sequences and executes them in the optimal order.
The result: less overhead, more flow.
- Plan or design while the Agent builds in parallel, no more constant context switching
- Submit requests in any order. Agent 4 handles dependencies and sequencing
- Stay hands-on where it matters, designing or vibe coding critical pieces of your app while the Agent works in the background on other tasks
Together, this unlocks faster iteration, easier experimentation, and more effective collaboration.
Agent 4 is a game-changer. Multi-user vibe coding via the kanban is a significant milestone for enterprises. It’s great for turning individual concepts into team realities and managing tasks through diverse role definitions
~ Takeshi Fujiwara, Director , SMFL Digital Labs
4. Create everything you need in one project
Historically, the Agent has focused on building apps. But real work is broader than that. You don’t just ship apps, you ship outcomes. And a huge amount of build time gets burned on workflow fragmentation: your app lives in one place, your deck in another, your data somewhere else, your launch assets scattered across tools, and every handoff costs time and context. Agent 4 is designed to allow you to seamlessly think, ideate, build, and iterate.
- With Agent 4, you can build:
- Web and mobile apps
- Slide decks
- Data apps
- Animations
and more within the same project—sharing the same context and design.
Just ask the Agent what you want to build in the prompt, and the Agent will build it for you. No manual stack selection needed.
- You can also chat directly with any services connected to Replit and ask the Agent to take action on your behalf. For example, the Agent can:
- Create Tickets in Linear
- Answer questions based on your notes in Notion
- Build or monetize your business with a storefront or local payment processing
- Query and analyze data stored in tools like Excel or Databricks
- You can also convert your existing web apps into mobile apps seamlessly, or build additional artifacts like slides or animations related to your existing web apps, within the same project.
This unification helps keep you in the flow- you can produce what you need without switching contexts. The same environment that contains your source code, design guidelines, dependencies, and runtime can also generate the outputs you need to launch. More finished work, fewer separate workflows.
Unlocking your creativity
Creative momentum doesn’t come from models alone. It comes from an environment built for real work—where building, running, iterating, and collaborating happen seamlessly in one place. That’s what protects your flow.
You feel it in the details: how quickly you can turn an idea into something tangible, how easily you can refine it, how naturally momentum builds, and how smoothly a spark becomes something substantial. When those pieces work together, creativity doesn’t stall—it compounds.
Agent 4 is designed for that creative loop—a faster, tighter rhythm between ideation and execution. It helps you move quickly without losing clarity, explore without losing control, and scale your ideas with confidence from first spark to finished product.
Because building with the Agent isn’t just about completing tasks. It’s about expanding what you’re capable of creating.
