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Backend Engineer and Blockchain Developer. Keep learning | Spread Knowledge

And deploy it using Remix IDE

Disclaimer: This article is only for informative purposes. It doesn’t recommend you to buy, sell or trade any cryptocurrencies, and doing so is highly subjected to market risks. The code is not suitable for production. The purpose is only to give an overview of how things work.

Right from the beginning of the DeFi Summer of 2020, a lot of new cryptocurrency and blockchain-related projects flooded the Ethereum network which resulted in the hike in gas price. People were in a situation to pay a 100$ gas fee for a 10$ transaction. …


Image by Pete Linforth from Pixabay

Welcome! In this article, we will be developing a secure and lightweight REST API using Node.js, Express server, and MongoDB from scratch that can be used as a backend for authentication systems. This is completely a beginner-friendly article.

As a bonus, I have explained how to create a simple referral system, using which you can share the referral code, and your friends can signup using that code. The concepts we will see throughout this article are completely generic, and it can be implemented using any programming language.

Agenda ✍️:

  1. User signup/registration with Email verification.
  2. User Login.
  3. Forgot password and reset password.
  4. Session…


A simple workaround that can save tons of gas!

Now-a-days, a lot of NFT projects are being launched every single day. During the public sale, the gas fee is going crazy.

Have a look at the picture below 👇


Using NodeJS & Ethereum Blockchain

Yeah! That’s true. Now we can send push notifications in a decentralized fashion using the public blockchain — Ethereum.

Push notifications are crucial in any applications for improving the user experience. People feel more engaged with the application and they prefer realtime information rather than delayed notifications through email or sms. But the DeFi space is still new and emerging everyday, it demands some way to notify their users that has nothing to do with their personal data. The only identity of the user in the DeFi world is his/her wallet address.

And that’s what the EPNS (Ethereum Push Notification…


Develop a lightweight, in-memory API rate limiter using Node.js.

Rate Limiting is one of the most important features which should be implemented in every web application. There are a lot of variations in the case of rate-limiting such as -

  • IP based rate limiting — preventing Denial of Service attacks
  • Account specific rate-limiting — protection against brute force attacks

In this demo, we will implement a basic rate-limiting mechanism that will lock the user’s account for X duration after Y consecutive invalid attempts. Also, we are not going to use any database for this, as I want to keep it more simple and precise.

I’ll be using Node.js to…


Leverage the Remix IDE

Drawing of faucet
Image by the author.

In this demo, we will be exploring how to create a faucet for your token using Solidity and deploy it to the Matic/Polygon live network. There are several reasons for a token to have a faucet. It can be a mainnet faucet used to distribute tokens to the community on the basis of some task completion, a testnet faucet to support developers building apps using the token, etc.

This article will focus on explaining how to:

  • Create a faucet smart contract.
  • Deploy it on Mumbai testnet.

Note: You can deploy this faucet on Ethereum or Binance Smart Chain (BSC) as…


Sentiment based trading-bot on Binance using NodeJS

Yes! In this article we are going to build a customizable trading bot, that can buy and sell Bitcoins on Binance based on the tweet sentiment whenever Elon musk tweets.

Question: Can you tell us the motivation behind this bot?

Answer: Sure, why not?!


A curated list for the beginners.

Nowadays, we can see a high rate in the adoption of blockchain technology and cryptocurrencies in particular. As a result, these technologies are transforming into an irreplaceable part of our day-to-day life. However, blockchain has reserved its place almost for the next decade because of its wide range of applicability.

Lack of trust and need for privacy paved the way for cryptocurrencies to become a trillion-dollar industry. Several projects and innovations in technology are emerging every day. …


P2PKH address generation using Node.js.

Photo by André François McKenzie on Unsplash

We are going to have a look at how to create your own Bitcoin wallets — Testnet and Mainnet, using a simple Node.js script. We can generate as many wallets (public/private key pairs) as you want instantly. We don’t need to use any third-party blockchain providers for this, as the wallet generation part is done offline.

In order to run the code given in this tutorial, we’ll need Node.js installed and configured on your PC which will not take even more than 5 minutes.

Without wasting much time on the introduction, let’s jump into the implementation part.

Currently there are…


Use Express.js, BullMQ, Cron jobs, and get email notifications

Stock price on phone
Photo by CardMapr on Unsplash.

Everyone in this world is busy and we often forget things. Motivated by these two statements, I decided to build a simple cryptocurrency price alert microservice that will send an email notification if the price of a specified coin goes above/below a certain threshold.

You no longer need to stare at the market to check the price all day. All you need to do is choose the currency and specify the threshold price. That’s it. You’ll get notified via the provided email address.

I used Node.js for the implementation. You can follow the steps below and build the same microservice…

Pranesh A S

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