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Engineering Articles

Engineering articles about Engineering from the people building Replit.

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20265 entries
JEAH

By Jon Eide and Aadil Hussaini

9m read
Cover artwork for the article “AI adoption starts with truth”.

AI adoption starts with truth

AI adoption is limited by trust. A user who gets burned by a confidently wrong answer will double-check the next one, eventually routing consequential work around the system entirely. Once that happens, AI remains a tool at the edges rather than infrastructure at the center… useful, but never trusted with the workflows where its value compounds. Before a company can benefit from more capable agents, those agents need a reliable way to know what the company considers true.

DFPZZLMC

By Daniel Furman, Peter Zhong, Zhen Li, and Michele Catasta

12m read
Diagram comparing a one-off human shipping decision with a continuous evaluation system that learns from production and ships improved agents.

Closing the loop: Evaluating and improving Replit Agent at scale

Most Replit Agent users start with an idea. They describe the goal in natural language — without a repo, test suite, or chosen framework — and expect the agent to turn it into a functioning app. The result might be a website, slide deck, mobile app, several connected artifacts, or something else entirely.

20256 entries
VF

By Victor Fuentes

4m read
Cover artwork for the article “Using Tvix Store to Reduce Nix Storage Costs by 90%”.

Using 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.

SKDHJZ

By Szymon Kaliski, Devin Halladay, and Jonathan Zhou

6m read
Cover artwork for the article “Introducing Workflows”.

Introducing 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.

TA

By Talor Anderson

2m read
Cover artwork for the article “Replit's All-new Database Editor”.

Replit'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.

20248 entries
LC

By Luis Héctor Chávez

16m read
Cover artwork for the article “So you suspect you have a memory leak...”.

So 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:

JZSK

By Jacky Zhao and Szymon Kaliski

9m read
Cover artwork for the article “Shell2: 200× faster, persisted, multiplayer-native Shells”.

Shell2: 200× faster, persisted, multiplayer-native Shells

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.

GSTR

By Gian Segato and The Data Team @ Replit

17m read
Cover artwork for the article “How Replit makes sense of code at scale”.

How Replit makes sense of code at scale

For any company making creative tools, being able to tell what its most engaged users are building on the platform is critical. When the bound of what’s possible to create is effectively limitless, like with code, sophisticated data is needed to answer this deceivingly simple question. For this reason, at Replit we built an infrastructure that leverages some of the richest coding data in the industry.

PS

By Patrick Stoica

2m read
Cover artwork for the article “Improved Dependency Management”.

Improved Dependency Management

We recently revamped the dependency management experience in your Replit workspace. You can now use and configure multiple languages in one Repl. We’ve consolidated language support, packages, and system dependencies into one new Dependencies pane for beginners and experienced developers alike!

CD

By Colton Donnelly

4m read
Cover artwork for the article “Searching Nixpkgs in Under 30 Milliseconds”.

Searching Nixpkgs in Under 30 Milliseconds

Today, we’re releasing the first version of rippkgs, a CLI utility for indexing and searching Nix expressions. With rippkgs, you can quickly search the nixpkgs available to your system with accurate results. Read on for more details about why we created it, how to use it, and how it works.

DS

By Devon Stewart

3m read
Cover artwork for the article “Replit + pip”.

Replit + pip

We’re thrilled to announce that first-class pip support is now available on Replit! This should work out-of-the-box when importing existing repositories from GitHub. For developers who want to switch from poetry to pip: start by deleting poetry.lock, then move your dependencies over from [tool.poetry.dependencies] to requirements.txt (structure hint: flask = "^3.0.2" would become flask>=3.0.2,<4 in requirements.txt), and finally, delete the other [tool.poetry...] sections from pyproject.toml. After that, the packaging infrastructure will use pip for all future operations going forward.

CD

By Colton Donnelly

4m read
Cover artwork for the article “Easier Editing for .replit Files”.

Easier Editing for .replit Files

At Replit, we want to make it easy to support any project configuration possible. This includes ensuring your binaries are in the right place and intelligent code completion works. Historically, the .replit file has been at the center of this, but the experience of editing the file is a process shrouded in mystery. While documentation exists for the file and what various configurations imply, it’s much more convenient if the documentation is visible inside the Workspace.

20236 entries
IK

By Ian Kirkpatrick

3m read
Cover artwork for the article “Landscape or Portrait? You Decide”.

Landscape or Portrait? You Decide

People have expected apps to rotate with their mobile devices since before the introduction of the iPhone in 2007. It’s especially important for productivity apps to adapt and let people choose how they want to utilize their screen space. With the newest version of the Replit Mobile App, you can now code in both landscape and portrait modes. This creates a significantly improved experience on smaller tablets like the iPad mini or larger phones like the Pixel Fold. Want to code on the go with your iPad mini? Simply rotate it to portrait, then later, when you’re home, connect it to your wireless mouse & keyboard and rotate it to landscape for maximal screen space. This is the first of many more improvements to the Replit Mobile App, unlocking your ability to build and launch your next startup from your phone.

LC

By Luis Héctor Chávez

3m read
Cover artwork for the article “Dec 12 Incident Update: Secrets and repl.co Static Hosting Unavailable”.

Dec 12 Incident Update: Secrets and repl.co Static Hosting Unavailable

Between Dec 12 and Dec 16, Secrets in interactive Repls and files in our legacy repl.co static hosting were unavailable. The root cause was a configuration push to GCS storage that was misinterpreted as a request for all the files to be evicted from storage. Deployments and Secrets in Deployments were unaffected. We have since recovered all known user Secrets and instituted new data retention procedures in our storage systems to ensure that this issue doesn’t reoccur. This will allow us to have a faster recovery going forward. This post summarizes what happened and what we're doing to improve Replit so that this does not happen again.

RM

By Ryan Mulligan

3m read
Cover artwork for the article “Skip the README, let us install for you”.

Skip the README, let us install for you

If you’ve ever tried to install a complex Python package, you know the pain of scouring the package’s README for the apt install or brew install commands necessary to bring in the system-level dependencies the package needs. This approach can be time-consuming and frustrating, especially when a cascade of errors indicates a missing system dependency — a pain point that isn't always immediately obvious.

JH

By Jake Hamilton

2m read
Cover artwork for the article “System Dependencies on Replit”.

System Dependencies on Replit

We recently released some improvements to our Packages tool, and now we're extending that work to bring a new System Dependencies tool to Replit, powered by Nix! Replit has bet big on Nix, and we're not slowing down. It's now easier than ever to leverage Nix's power with a brand-new user interface for adding, removing, and searching system dependencies.