Introduction HackerEarth has lots of candidates getting evaluated on a daily basis. We have a feature that benchmarks candidates across the platform. Benchmarking is the process of creating the profile of the ideal candidate for a position, and then measuring all candidates against that profile. To ...

Introduction HackerEarth handles millions of requests every day. To understand the user access patterns, get the usage of any particular feature or a page, figure out the daily active users or users who have been active for the past 6 months, etc in near real time, it is important to stream that dat...

Asynchronous background jobs can dramatically improve the performance and scalability of web applications by offloading resource-intensive and time consuming processing from the request-response cycle of an application. Last year, in an effort to make our asynchronous flows more reliable, secure, an...

During my internship at HackerEarth, I faced an interesting problem. This blog is about that and how I solved it. Problem: To set a background image to the textarea element. My initial impression on seeing the design was that it would be easy. I thought it’s a image but after exploring the code I ca...

“Hey the deployment is broken again. Can you push this change again” “Hey, I merged my changes were merged in the morning. I still don’t see them in production yet” “Argh, the static files are not updated. We have to run deployment again” These voices hollared across the hallway and this was followe...

In 2016, I was working to build a platform to help NGOs raise donations. The platform was supposed to be built using React. The beautiful designs were in place. I was excited to build some new features as well as to try out the new architecture using Redux on a larger scale. Yes, this was the time w...

Our older test creation flow had several inherent problems associated with it: 1. Profile drivenEarlier to this, we had test creation based on job profiles (role-based), which was restrictive as the skills were tightly coupled to the roles and were not customizable by the recruiters. For example, I ...

Earlier in 2016, I came up with the idea of creating a Python module which could provide functionality of profiling functions w.r.t. SQL queries and tell exactly at what lines of function, the queries were happening. I called that package Goofy and created it with the engineering of Python AST manip...

Introduction HackerEarth has grown into a platform that serves a huge number of customers for technical assessment. To make this possible, we try our best to make the platform as easy-to-use as it can get. At several places in our Recruiter Dashboard, we used to have a Markdown editor to allow users...

History We at HackerEarth created a single-page document with common and special CSS classes to make layouts, grids, buttons, inputs, tables, tooltips, and form elements in late 2017. That was our first attempt to develop on our own front-end framework. Old Nuskha screens: Framework is a platform, f...

HackerEarth prides itself in its scalable & automated evaluation system. What was initially designed keeping standard programming problems in mind (check this post out), gradually evolved to accommodate a plethora of problem types across various tech domains. Currently supported Problem Types Progra...

Introduction The infrastructure that powers a product and all of the services that it provides can be huge and complex because the product is scaled to serve millions of users. In most cases, each service might depend on various components for seamless functioning. With a product that houses a varie...

ReactJS, as the name suggests, helps create reactive (read interactive) UIs. If we have a UI with many interactive elements and on each interaction a bunch of elements change, ReactJS efficiently updates and renders the required elements. At HackerEarth, one such UI is the programming assessment env...

If you are here searching for answers about Minimum Viable Product or you are here as a result of watching the first episode of the first season of Silicon Valley, this might not be the blog you are looking for. If you are a software engineer and you develop apps (especially on Android), this is a m...

At hackerearth we send emails to keep our users updated on upcoming challenges and their activities, for example, when a user successfully solves a problem, receives test-invitation, updates on user comments. Basically whenever it is appropriate. Architecture It takes lot of computational power to s...

Introduction: By nature HackerEarth has so many programming puzzles. These puzzles bound to have mathematical equations, statements and symbols. Problem Setters often requested us to add support for Latex. Implementation: The obvious and easy solution for this is to implement Latex support for indiv...

Objective In Jan 2015, HackerEarth conducted nearly 10-12 hiring challenges, 5-6 coding challenges and numerous college challenges. HackerEarth has a decent social media presence and we wanted to inform our followers about the events at HackerEarth. One of the main objectives of this project was to ...

We at HackerEarth regularly conduct 24-hours internal hackathons usually once a month to boost ourselves to get familiar with new technologies and to come up with great ideas and hacks to increase our productivity. A hackathon project can be anything from creating a new product to creating some tool...

Introduction One of the primary issues when gathering information from users is suggesting the right options that they are looking for. At HackerEarth, we gather information from all our developers which help us provide them a better experience. So there came a time when we had to suggest very smart...

HackerEarth Recruit, is a platform for technical recruitment. Many companies use this platform for candidate assessments and interviewing. There can be multiple admins for a company account. As teams grow in size, access control is a special concern for applications that deal with financial and priv...

We had implemented a javascript logger to capture the pesky issues our users faced and had problems when using the site. When we came up with the idea, we thought it would be just a five minute job where we would just have to add a snippet and would be done, but as it is well know, nothing is simple...

Whenever we roll out an improvement on our platform, we at HackerEarth love to conduct A/B tests on the improvement to understand which iteration helps our users more in using the platform in a better way. Since the available third party libraries did not quite meet our needs, we wrote our own A/B t...

We, at HackerEarth, cater a huge number of questions in Assessment tool. Recruiters can choose from wide varieties of Multiple Choice and Programming/Coding questions to assess candidates. Every week or two, new questions are added to the Questions Library. As the time passed, thousands of questions...

HackerEarth’s web servers handle millions of requests every day. These request logs can be analyzed to mine some highly useful insights as well as metrics critical for the business, for example, no. of views per day, no. of views per sub product, most popular user navigation flow etc. Initial Though...

###Introduction HackerEarth uses django framework at its heart. We use two third party django packages for the purpose of user authentication and session management: django-allauth: Provides pre-built modules for email-based as well as all popular social authentication mechanisms. django-redis-sessi...

In this post, I am going to briefly descibe the challenges we faced while building a powerful comment system. Comments have become an integral part of our website. They are integrated almost everywhere - challenges, problems, notes etc. and soon will be added to our new products. We have been workin...

HackerEarth infrastructure is hosted on Amazon services. At any given point of time many webservers are running concurrently serving thousands of requests. This generates tons of access and error logs on each server separately. The task here was to parse the logs on all these webservers and store th...

One of the most liked feature of the newly launched HackerEarth profile is the accounts connections through which you can boast about your coding activity in various platforms. Github and StackOverflow provide their API to pull out various kinds of data. The API documentation of Github and StackOver...

We have been constantly adding features to our HackerEarth Developer Profile, making it better with every new update. One of the exciting data in it is HackerEarth Streak on the HackerEarth Activity page. This post explains how we process user data and compute such results. We split it into two part...

####Setting up a Google Project In order to use any of the Google APIs for your application, first you need to set up a project in the Google Developer’s Console. Enable all the APIs that you want to use in the APIs tab under APIs and auth. Under the Credentials tab, create a Client ID and Client se...