I created this piece for the purposes of entering the AWS x Vercel H0 Hackathon. #H0Hackathon

What I built

I built Cast Wide, a tool that takes one idea and rewrites it for different platforms like Twitter, LinkedIn, and Reddit.

The important part is that it does not just paraphrase. It actually changes the structure, tone, and writing style so the content feels natural on each platform.

For example:

• LinkedIn output is more structured and professional


• Twitter output is short and direct


• Reddit output is more conversational and context-heavy

You enter one idea and get three different versions that are ready to post.

How it works

The system is built with Next.js and deployed on Vercel.

When a user submits an idea, the backend API does three things:

First, it takes the input idea and creates three separate prompts, one for each platform.

Second, it sends all three requests to Groq at the same time using Promise.all so nothing runs one after another.

Third, it collects all responses and sends them back to the frontend in one response.

This keeps the experience fast even though we are generating three full outputs.

Data storage

Every generation is saved in AWS DynamoDB.

Each record stores:

• the original idea


• selected platforms


• generated outputs


• timestamp and user id

The table uses userId as the partition key and createdAt as the sort key. This makes it easy to fetch a user’s history in order without complex queries.

What I learned

The hardest part was not the UI or the API calls. It was making sure each platform output actually felt different.

At first, the model kept giving similar answers with small wording changes. The fix was fully separating prompts per platform and removing shared instructions that caused overlap.

Once I did that, the outputs became much more distinct and useful.

Built for

AWS x Vercel H0 Hackathon

This project was built solo.

Try it out: https://cast-wide.vercel.app/

H0Hackathon