El Corillo Morcillero 2025: Parrandas, Tradition and an App

“Me hace feliz todo lo que pueda hacer para que permanezca nuestra tradición y motivar a los jóvenes para que también mantengan ese legado que vino de nuestros ancestros. Eso es responsabilidad de todos porque el pueblo que pierde su tradición desaparece, pero hay personas dispuestas a mantenerla” — Herminio de Jesús

The holiday season is my favorite time of year for many reasons, and one of the biggest is parrandas — especially El Morcilla Tour, a parranda group organized by my closest friends and family. Starting on Black Friday, we have a full calendar of parrandas that usually runs through the San Sebastián Street Festival in January.

This year I wanted to level up the parranda experience, and my brother shared an idea about building an app for El Morcilla Tour. My first thought was: “Finally, I’m going to build something that solves a personal problem.” And in no time, parranda.app was born — with our official songbook and meeting points (accessible only to approved members). I worked on the app during nights and weekends, between breaks taking care of the baby. And 100% of the code was written by an LLM. If that’s what you’re here for, feel free to skip ahead to that section. In this post, I want to share a bit about El Morcilla Tour, parrandas, and how I built parranda.app. Let’s get into it.

What is a Puerto Rican Parranda?

Don Herminio de Jesús, known as the father of the Puerto Rican parranda, wrote “Historia de la celebración navideña en Puerto Rico” (History of Puerto Rico’s Christmas Celebrations), which tells the complete story of where this tradition comes from and includes a full guide on how to run your parranda. I discovered the book a couple of years ago because my dad, the pianist of El Corillo Morcillero, bought it and lent it to me. That’s a story for another day.

Parrandas in Puerto Rico are one of the most beautiful Christmas traditions, and in my opinion, the best holiday hangout in PR. A parranda isn’t a band or a live show like the ones at festivals. It’s a group of friends and family who come together to “surprise” someone with music and joy. They usually happen late at night, and those who receive the parranda welcome it with love because the songs we sing are an integral part of Puerto Rican culture. We sing, we dance, we celebrate, we eat, we drink, and above all, we keep our tradition alive.

El Morcilla Tour

Our parranda group is called El Morcilla Tour, and its members are El Corillo Morcillero. Our motto is simple: “Tu me das morcilla, y yo te doy el resto!” (You give me morcilla, and I’ll give you the rest!). The houses we visit only need to welcome us with morcilla, and if an asopao sneaks in, we’re not complaining. We’ve never been short on musicians or singers at the parrandas. We’ve also never lacked good people willing to host the parranda. My sister has been coordinating this group for about 10 years now. I’m not sure if it was after Hurricane María or after the pandemic, but at some point the group started growing exponentially. This year we even made it on TV and brought parrandas to houses farther than ever before. This season, several new people joined and helped take the music to another level. With the piano, bass, güiro, and all the other instruments that are always with us, we gave it our all and had the best parranda season yet.

It’s worth mentioning that we have some basic rules for anyone who shows up to a parranda and wants to be part of the crew. If you don’t follow them, you can’t be part of it:

Dance and sing, even if you have two left feet and can’t carry a tune
Respect the house we’re visiting as if it were your own
No smoking inside the house or nearby
Bring your own drinks and Christmas accessories

Now let’s get to what you came for. Let’s talk about Parranda App.

Parranda App

On November 10th, I got the message with the idea for the app, and the next day I started coding:

Morcilla Tour App: Features:

Map and Date of parrandas (Revealed by owners)

Buy Merch from the App

Upload Parranda Pics into a private Morcilleros Feed

Songbook

Gamified experience - Badges for attending parrandas

Badges for singing / bringing instruments

Sing along

AR Experiences

I didn’t build everything from the original idea. Here’s a quick timeline of the project so far:

Nov 11-17: Initial design and implementation in React Native
Nov 18-24: Spinning my wheels trying to launch on iOS and Android
Nov 25 - Dec 1: Pivot to launching as a web app under parranda.app
Dec 2-9: More wheel-spinning on a gallery feature that didn’t get used
All of Dec: Adding songs and improving the user experience

As you can see from the timeline, I spent a lot of time spinning my wheels (not making much progress). That’s not necessarily bad since it’s part of the learning process. I started the project thinking it would be an app people could download from the app store. Unfortunately, that approach doesn’t work if you want to ship fast, especially when you’re working with limited free time. It also doesn’t work if you want people to register and login. On top of that, I took this opportunity to dive deeper into Supabase because I’d seen it around and wanted to try it on a project. Bottom line: I spent too much time on tasks that weren’t valuable for the project.

With just a few days left before the first parranda, and after demoing the app to my sister, I decided to pivot to web. It literally took 1 prompt and some testing time to get it running on react-native-web. For the website name, we considered morcillatour.com or something like that, but parranda.app came up as a catchy name that could serve any parranda group. Vercel was key to shipping the web app quickly and easily.

The Songbook: The Star Feature

The star feature of the app this season was definitely the songbook. We have a PDF songbook that we always use, but the UX of opening a PDF on your phone and navigating through it is terrible. People were often trying to figure out what the lyrics said while panderos, cowbells, güiros, and the rest of the music were going full blast. With the digital songbook, our chorus of 100+ people sounded way more in sync than before. When everyone in El Corillo Morcillero has the lyrics, they can focus more on singing, dancing, and having a good time.

During the parrandas, I got to experience the real power of tools like Claude Code Web, which helped me address bugs and feedback live without missing a beat, and more importantly, without missing the parranda. From login issues, to UI/UX fixes, to adding new songs to the songbook, I could do all of that from my phone to GitHub and from GitHub to production. The original plan was for people to register via email to access the app’s content, but in the end I moved the songbook to be accessible right from the home screen.

The Workflow: Prompt → PR → Preview → Deploy

I used Claude Code and Codex to write 100% of the code. The workflow went like this:

Write a descriptive prompt with context
The AI tool generates the code and creates a PR
Vercel automatically generates a preview URL
Test on the preview, and go back to step 1 until I’m satisfied
Merge → Automatic deploy

Let’s look at a specific example to see the workflow up close.

When I pivoted to web, I had to rethink the tab navigation since it doesn’t work well for a mobile web app. This was the prompt I used:

“Use the frontend design skill to rethink the navigation. Remove the tabs and put all of the options in the Home Screen: songbook, parranda events, profile, gallery. Use chrome devtool mcp, run the web version of the app in demo mode so you can see the screen and come up with a solid UI”

Anthropic’s frontend design skill helps the model think through UI considerations much better. Combined with MCP (Model Context Protocol) — Claude Code can connect to Chrome DevTools to see the app live while making changes and thinking about the design. This let me iterate on the design without having to describe every detail. Claude could see what I was seeing.

By the end of this session, the home screen was much cleaner with all options accessible, optimized for parranda use where people are standing, phone in one hand and a güiro in the other. That’s how I built all the features in the app. I spent time thinking about architecture, features, and other important software engineering details, but the hands-on coding work was mostly done by Claude Code.

Iterating Live During the Parrandas

With the release of Claude Code Web, things got interesting. I could make changes to parranda app from my phone during the parrandas. I made it my goal to address people’s feedback as fast as possible, and if I could do it during the parranda, even better. Claude Code Web was clutch for this. During the parranda rehearsals, while the corillo was singing, I was in a corner shipping deploys.

Check out the screenshot below with a list of sessions in Claude Code from my phone. Each one represents a change I made live:

“Add Doña Tere song to songbook” — A new song that one of the new morcilleros brought. In 2 minutes it was in the songbook.
“Add next and previous song navigation” — During the first parranda I realized this UX was missing to move between songs. Another PR in less than 15 minutes.
“Update house rules title and dancer emoji” — Little UX details you notice when 100 people are using your app at the same time. As I mentioned above, it’s super important that people who join follow El Morcilla Tour’s rules.

The flow was: someone tells me something → I open Claude Code on my iPhone → describe the change → Claude creates the PR → Vercel generates preview → I verify it works → merge → deploy. All in under 10 minutes, no laptop, without missing the parranda. Web is much faster to deploy than a mobile app, and much easier to iterate and make changes. This was true before LLMs and it’s still true today.

This is what LLMs enable today: the ability to iterate at the speed of feedback. You no longer have to wait until you get home, open your laptop, and try to remember what the bug was. You fix it in the moment, with fresh context.

Next Steps

Before the San Sebastián Street Festival, I’m going to add all the famous plena choruses so anyone who wants to play, sing, and dance can do it. The plan now is to have the most complete parranda and plena songbook out there — something that can serve as a reference for any parranda group, and a way for me to contribute my grain of sand just like Don Herminio did (and continues to do). It’ll also help me actually sing the choruses without dropping the ball. I have other ideas in mind for parranda.app, but I might save them for the next Morcilla Tour season. The motivation comes naturally when you’re building something for your friends and for the culture.

Do you have your own parranda group? Check out parranda.app and use the songbook. It’s ready for the San Sebastián Street Festival, or your next family party. If you want to contribute or have feedback, hit me up.

🎶 ¡El Que Quiera Morcilla, QUE SE LA COMA! 🎶