Sep 26, 2023

How I built a ChatGPT Application in WhatsApp during my free time

Hey there friends! Gather around, as I unravel the tale of how I created a mind-blowing application, Plik, on WhatsApp, all within the confines of my free time. Get ready for a journey packed with adventure, innovation, and a lot of code!

Vitor Águila
by Vitor Águila
How I built a ChatGPT Application in WhatsApp during my free time

The Birth of an Idea

First off, this was a delightful challenge I set for myself, complete with a deadline of one ambitious month. With most of my work done under the calm gaze of the moon, my mission was to craft and mold the backend, infrastructure, and integrations of Plik from mere ideas to reality.

Here's how it all began: noticing a gap for non-tech-savvy individuals in using advanced AI like ChatGPT, I was propelled by a question - what if WhatsApp, a platform even my mom uses, could bring ChatGPT to everyone's fingertips? That electrifying thought set my gears in motion. With over 2 billion users worldwide, WhatsApp reigns as one of the most popular messaging platforms, seamlessly connecting people across continents. It's a hub for personal conversations and business communications.

The Chosen Name

Here's a fun bit for you all: after several rounds of brainstorming, I landed on the name Plik for this project. You can find this brilliant application on its domain at .The name and the logo were conceived amidst a volley of ideas, all developed and refined through many prompts via ChatGPT.

The Journey of Building Plik

My journey with Plik first led me to Twilio for a WhatsApp integration experiment. Although useful, I found more clarity in WhatsApp's own well-detailed documentation, and thus, embarked on understanding the WhatsApp API and the world of webhooks.

For the technological backbone, my choice was clear. Utilizing Node.js for the backend, Postgres for the database, and Vercel for effortless infrastructure setup, the development sailed smoothly. Feature ideas burgeoned, adding exciting dimensions to Plik. Users could send audio and receive responses in the same language, choose from four different languages, and even request images via text or audio!

The Magical Features

Wondering about the coolest features? Here’s the rundown:

  • An awesome language selection feature that enables interactions in English, Portuguese, Spanish, and German.
  • The power to convert received audio into text using OpenAI Whisper, send it to ChatGPT, and then convert the response back into audio using AWS Polly!
  • A user-friendly image request feature, integrated with stableDifusion.
  • An exciting affiliate program, allowing users to earn credits by inviting friends.
  • A smooth payment mechanism using Stripe, offering both credit top-ups and monthly subscriptions.

For each service request, a carefully calculated cost structure, encompassing OpenAI Whisper, AWS Polly, WhatsApp API, and OpenAI ChatGPT, ensures affordability and transparency.

The Structure

Like a well-oiled machine, the backend, created using NodeJS and hosted on Vercel, operates through various serverless functions. Services like KV (redis), Edge Config (for feature toggles), and Postgres enhance the efficiency and functionality of Plik.

Incorporating another AI service,, I built multilingual tutorials and welcome messages, enriching the onboarding process for new users.

The Finishing Touches

A huge shout-out to my brother-in-law, Joel Luis who lent his exceptional skills to build a stunning landing page using NextJS. His commitment to testing and refining every feature played a crucial role in perfecting Plik.

In Conclusion

My journey in creating Plik, bringing ChatGPT to WhatsApp, was a whirlwind of learning, innovation, and collaboration. With a seamless backend development hosted on Vercel and diverse features powered by OpenAI, Plik stands as a beacon of what passion and dedication can achieve. If you're eager to know more technical details or have a similar idea, feel free to contact me! Visit Plik at and dive into the world of convenient and fun AI interactions on WhatsApp!

#Vercel #OpenAI #AI #BackendDevelopment #Plik

That's the end of the journey, folks! Unleash the power of AI with Plik, and let’s keep creating, innovating, and making the world a more connected place.

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