Thu, Mar 13, 2025Agent Just Got Eyes — Click. Describe. Done.
Making changes to your app should be as fast as possible. Instead of manually describing what to edit, what if you could just click? Now you can. Meet Element Selector, a simple yet powerful way to select any UI element in your app and modify it instantly with Agent or Assistant. No need to type out descriptions or search through files — just Click. Describe. Done. How It Works Toggle the Element Selector — You can find it alongside the chat input tools in Agent and Assistant. Click to select — Want to edit a button? Change a heading? Just click it. Describe changes — Assistant updates text, colors, or styles in seconds. Use Agent to add features like turning a static list into a searchable one.
Sat, Mar 8, 2025Everything you need to know about MCP
You can find the 3-min quickstart from the video here What is MCP? MCP (Model Context Protocol) is a standard way to connect AI models to data sources and tools. It allows AI to access information and capabilities beyond what they were originally trained on. MCP works like a universal connector for AI systems. Just as standard ports let different devices work together, MCP lets different AI models connect to the same tools and data sources. This means developers can build a tool once and have it work with any AI model that supports MCP. It's like the USB-C port of AI applications.
Wed, Mar 5, 2025Using Tvix Store to Reduce Nix Storage Costs by 90%
For the past few years, Replit has been using Nix to serve packages/dependencies and provide consistent development environments to our users. Nix on Replit allows users to have access to a large number of packages and libraries that can be seamlessly integrated into a user's project. Motivation In order to quickly serve thousands of packages to our users, we attach a large Nix store persistent disk to all development containers serving Replit apps. While this approach has worked well for a while, this persistent disk grows with every subsequent NixOS release (eventually reaching a size of 20Tb). When considering ways to reduce the size of this disk, one important constraint was to never remove store paths from the cache. Project that depend on packages in older Nix channel releases could still link to these store paths, so in order to maintain backwards compatibility those store paths must remain. Tvix Store Tvix is a new modular implementation of Nix that contains a series of components that can be used individually. One of these components is the Tvix store. tvix-store is a Nix store implementation backed by the tvix-castore. The tvix-castore manages blobs (file contents) and directory info (file metadata, like names, permissions, etc). tvix-store manages nix path info metadata, effectively creating a mapping of Nix store paths to tvix-castore contents.
Thu, Feb 27, 2025Introducing Workflows
With Workflows, you can easily save your development processes and organize them as a sequence of Tasks. Instead of having to repetitively type commands into your shell and remember them, Workflows provide an intuitive interface to configure your frequently used commands and execute them with the click of a button. Simplifying development with Workflows Workflows give you the ability to better organize your project execution pipeline, while offering an accessible interface to reuse them. Using the Workflows pane, you can easily configure specific buttons to run specific commands, and even link multiple Workflows together in a chain. Instead of copy pasting "cd ./client && npm run dev && cd ../server && node server.js", you can define the procedure as a Workflow with multiple Tasks. Let's see how it works with an example.
Wed, Feb 26, 2025Replit's All-new Database Editor
This week, we launched a new Database Editor feature on Replit. This feature is another addition to Replit’s full suite of tools that make it easy for anyone to build an app — no coding knowledge required. When you build an app on Replit, you get a fully-functioning project that’s ready to send out to the world. This includes real databases powered by Postgres: the most popular database in the world, that powers many of the applications you use every day. Did you know? Postgres is used by half of all professional software developers, according to StackOverflow’s developer survey. Replit handles all the setup and management of your databases, so it’s never been easier to get started. Now, we’re making it even easier to use databases on Replit. Inside your app’s workspace, head to the “database” pane, and click to the “My Data” tab. Here, you’ll see a spreadsheet-like view of your app’s data.
Tue, Feb 25, 2025Introducing Replit Agent v2 in Early Access
Smarter with realtime app design preview In partnership with Anthropic’s Claude 3.7 Sonnet launch, we're excited to announce the release of Replit Agent v2 in our early access program. The early access program is available exclusively to users on Replit paid plans who have opted in to Explorer Mode (for instructions on opting in to Explorer Mode, see below). While we're encouraged by initial results, you may encounter speed bumps and areas needing improvement as we continue development. What's new: A more autonomous Agent
Tue, Feb 4, 2025Replit launches the first software creation Agent on iOS and Android
You've always wondered why that app didn't exist. Now you can — Make an App for That. We’re thrilled to announce that everyone can now try Replit Agent for free! Check out what we’re launching: Replit launches the first software creation agent on iOS and Android — use our AI app builder to build and deploy apps from your iPhone or Android. Chat with Agent as if texting a friend, and watch as it writes, deploys, and hosts your app in real time — no laptop required. Free Tier for Everyone: Replit Agent is now accessible to everyone with a free tier that includes trying Agent, making it easier than ever to start building apps!
Thu, Jan 30, 2025Repls are now Replit Apps
Today we made a big update to how we name things on Replit. What we previously called “Repls” are now “Replit Apps”, or just “Apps” for short. It’s a better description of what users are building on Replit today, and more in line with how we name things. REPLs are something we’ve always been a fan of at Replit. The read-eval-print-loop is one of the fastest and most intuitive ways to understand programming, try ideas, and get feedback. Those are all values we try to instill in the product to this day. The name Repl on Replit goes way back, even further than the company itself. When Amjad first launched a project to make coding in the browser easier, it was called JSREPL because it gave you a JavaScript REPL right in the browser. No installing tools, just write code.
Thu, Jan 16, 2025AI Coding is Better with Python
"Can everyone really code with AI?" I hear this question all the time. Usually after someone sees a viral post about an AI-built app and thinks "I could do that too!" But here's what those posts don't tell you: most AI-generated apps are just pretty shells—nice looking websites that lack functionality. Why? Most AI coding assistants build with JavaScript and are optimized for presenting information to the user (frontend development). These apps lack the backends and services that power functional applications. JavaScript is great. It creates beautiful frontends—Replit’s AI tools use it well. But Replit is unique: we don’t only use JavaScript. In fact, there are many times it’s not the right tool for the job. Perhaps you’re:
Tue, Dec 10, 2024Announcing the New Replit Assistant
Today on Replit, anyone can take their ideas and turn them into software — no coding required. For nearly a decade, Replit’s mission has been to bring coding to the next billion people. We’ve helped millions of people learn to code and made programming less intimidating. But now, thanks to our Agent and Assistant, our AI coding products, we’re taking a giant leap forward. You don’t need to learn coding to be a creator — you just need an idea. From local realtors in Cleveland to Japanese influencers to product managers at some of the world’s largest enterprises, people are building incredible things on Replit. We no longer need to limit ourselves to being users of software, we can all be creators. Today, we’re taking Replit Agent out of early access and officially launching it with groundbreaking updates that will radically expand who can create software. Let us show you what’s possible.
Tue, Nov 26, 2024So you suspect you have a memory leak...
Programming languages with Garbage Collectors are fantastic! You no longer need to keep track of every single piece of memory that your program needs to run and manually dispose of them. This also means that your programs are now immune to bugs like double-free (accidentally freeing a resource more than once, leading to crashes or security vulnerabilities) and most memory leaks (accidentally not freeing a resource, leading to crashes by running out of memory). But it is still possible to have a memory leak. Consider this TypeScript snippet: The global cache makes fibonacci fast, but it relies on a global cache that has no way of being cleared, so it will always accrue memory when it is called with larger and larger numbers. Slowly but surely. At some point during the development of Replit Agent, one of our engineers spotted the following graph in our dashboard: We had strong evidence that the agent processes were running out of memory roughly once an hour, and that likely means a memory leak. Since we were constantly serializing each agent process’ state to its Repl, we were able to recover without losing any data, but that meant that we had to re-run several LLM calls, and those tend to add up. This also implies that users would sometimes see some spurious slowdowns, so that was suboptimal too.
Wed, Nov 13, 2024Zero to MVP
Since joining Replit, I’ve faced a harsh truth—I’ve never written a line of code. As a UC Berkeley student studying business journalism, coding feels out of reach. I’ve had countless app ideas but would always hit the same wall: Who can build this for me? That’s until I discovered Replit. It's a platform that brings ideas to life fast—no technical background needed. Replit bridges the gap between creative vision and actual execution. Making Ideas Happen
Tue, Nov 12, 2024SpotHero: Innovation through Rapid Prototyping
SpotHero: Innovation through Rapid Prototyping With Replit Teams, the SpotHero marketing team has developed internal tools, data integrations, and prototypes to seamlessly and cost-effectively integrate disparate departmental systems. “Rapid prototypes that don’t tie up product and engineering teams with unproven methods are vital for innovation. Replit enables us to cycle quickly, helping us determine which projects are worthy of greater effort from our limited internal teams and which should continue to run departmentally.” SpotHero overview SpotHero is the leading parking reservation marketplace that helps drivers find, compare, and reserve parking across 300+ cities in the U.S. and Canada. Since being founded in 2011, SpotHero has helped drivers park over 75 million cars.
Mon, Nov 4, 2024How we name things
What’s in a name? Well, a lot, but first and foremost: stress. Whether we’re naming our babies, pets, companies, or features, we tend to worry a lot about finding the perfect name. We know intuitively that a name will shape how something is perceived and even influence its direction going forward. And yet, this stress isn’t equally distributed. In business, people tend to think a lot about the names of the companies they’re building but leave each product and feature name up to whoever thinks of the best-sounding name first.
Fri, Oct 11, 2024Shell2: 200× faster, persisted, multiplayer-native Shells
What even is a terminal? Back when computers were still in their infancy, the “computer” usually was a big cabinet in the middle of a room. They typically exposed some internals via a front panel with lots of knobs and ports. Users would connect a terminal device (sometimes called a teletype or a TTY) to this front panel in order to input text and print the corresponding output. In the 1970s when microcomputers like the Apple I started becoming more mainstream, displays and keyboards started to be integrated into the computers themselves. The rise of the graphical user interface meant that the displays and keyboards weren’t just used for the terminals themselves but for various other graphical programs too. At some point, smart computer people thought “wait a minute, we can make a graphical program that just emulates what a terminal would have done anyways!” and thus the terminal emulator was born. In these emulators, the wires of the traditional TTY are replaced with pairs of file descriptors (an abstraction for a stream of bytes) known as the PTY (short for pseudo-TTY). Importantly for Replit, the PTY doesn’t use a serial port to connect the TTY to the computer which means we can operate a PTY remotely over a network!