What does a Full Stack developer do: solving bugs in a streaming app?

11 April 2025
5 minutos
Blog

It happens more often than streaming content companies would like to admit. A user opens that video-on-demand app on their mobile phone or tablet and discovers that the screen is blank, that the recommended series are not loading, or that they are no longer offered the possibility to continue watching that film they have left halfway through.

What might appear to be a simple visual glitch is in fact a complex technical problem involving multiple layers of development, from the user interface to the servers that manage the data. Solving it requires not only specialised knowledge, but also speed, analytical skills and a holistic view of the system.

This is precisely the kind of challenge that Lucia, a full stack developer, faces. As a professional, she must be prepared to act decisively when something goes wrong, understand where the problem lies, coordinate with other teams and find an effective solution in record time. Today is a decisive day: the platform is premiering one of the biggest series of the season and this technical failure threatens to tarnish the company's reputation.

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A day in the life of a full-stack developer: fixing a glitch on a streaming platform

8:30am - Early warning: something is going wrong in production

Lucia has started her day like any other, but her phone vibrates with a critical alert: the app has stopped showing personalised recommendations to users. Something is going wrong because Sentry, an application that monitors errors in applications and reports them automatically, has detected it.

Without letting panic get the better of her, she quickly connects from home, logs into the system and starts reviewing what is happening in real time. She knows that if it's not resolved quickly, thousands of people will have a bad experience... and that's something a good full stack developer can't afford.

Before going to work, she communicates with her team through her Slack channel and coordinates the tasks to be carried out in Jira, a project management and incident tracking tool.

9:00 a.m. - Team meeting: prioritising and distributing tasks

In a quick meeting via video call, Lucía and her team analyse the situation. She offers to take control of the complete diagnosis, as she masters both the Front-End (what the user sees) and the Back-End (the logic that makes everything work behind the scenes).

This is the value of a Full Stack profile: being able to jump between software layers with ease, detect where the fault is and act without having to depend on different teams.

9:30 h - First stop: the user interface (Front-End)

Lucía opens her development environment and reviews the application code. The first thing she does is to check if the interface is receiving the data correctly. She simulates a user accessing his account and... the screen, as reported by the early warning, appears empty.

You try entering simulated data and this time, to your relief, the application responds correctly. Thanks to using Postman, a tool for testing APIs and checking if the data arrives correctly from the server, he gets some clues about the source of the failure: something is not working as it should in the Back-End.

11:30 h - Second stop: the logic of the system (Back-End)

With the Front-End out of the way, Lucia dives into the invisible part of the app: the Back-End. Here is all the logic that connects each user to their favourite series.

First of all, she checks the server code, where the personalised recommendations are generated. He dives into MongoDB Compass, an application that allows him to explore and debug data in the MongoDB NoSQL database on which the platform is based.

He finds the bug: a badly formulated query. This causes results to be returned incorrectly and, as a result, the app does not display anything on the screen. Using Node.js + Express.js, a development environment for building server logic and APIs, he fixes the bug and adds a security condition: if no custom recommendations are generated, the system must display popular titles by default.

13:00 h - Validation and problem resolution

Before applying the change for all users, Lucia tests it in a controlled environment. She runs a series of automated tests to make sure everything works correctly, without breaking other parts of the app. Jest, a framework commonly used to write and run automated code tests, becomes her main ally.

Because he wants the rest of the team to be able to validate the changes as well, he uploads them to the company's Git repository, ensuring that if it gets the go-ahead, it can be deployed to the production environment in an automated fashion.

With the job done and the application back up and running as it should, Lucia takes a breather. Before she tackles the next project, she reviews a technical newsletter on new ways to optimise APIs for streaming platforms. She knows that in the world of development, learning never stops.

In fact, in the afternoon, he spends some time researching GraphQL, a technology that could help make database queries more efficient in the future and prevent errors like the one the application suffered that morning from happening again.

She also documents everything she learns in her team's knowledge-sharing system. A good Full Stack developer doesn't just solve problems: she also leaves everything ready for others to learn from her experience.