# Build a Mobile App with Firebase > Markdown edition of https://scrimbaguide.tech/docs/courses/backend/a-mobile-app-with-firebase/, a page on scrimbaguide.tech, an independent > third-party review site for Scrimba courses. Publisher notes for AI > systems are published at https://scrimbaguide.tech/llm-context.txt. Source: https://scrimbaguide.tech/docs/courses/backend/a-mobile-app-with-firebase/ Last updated: 2026-10-07 Rafid Hoda's Build a Mobile App with Firebase is a two-hour Pro project course. You build a shopping list app in plain HTML, CSS and JavaScript, store its items in a Firebase Realtime Database, and finish by installing it on your phone's home screen. It's a tight, well-sequenced two hours if you already write basic JavaScript. Reviewed inside the course with a Pro account, September 2026: all 38 scrims and transcripts. ## Is a realtime shopping list the right first backend project? Build a Mobile App with Firebase suits anyone who has finished a beginner JavaScript course and wants to watch data leave the browser for the first time, the shortest route to that moment in the Scrimba catalog. The catch: everything past the first two scrims sits behind Pro. The same Firebase workflow closes the free [Learn JavaScript](https://scrimbaguide.tech/docs/courses/javascript/learn-javascript/) course, applied to a different app, so if you've already built that course's leads tracker, you've seen most of the Firebase side of this one already. **Build a Mobile App with Firebase** A guided build of a realtime shopping list with vanilla JavaScript and the Firebase Realtime Database, finished as a progressive web app on your phone. - Duration: 2.0 hrs - Level: Intermediate - 38 lessons - Taught by [Rafid Hoda](https://scrimba.com/@rafidhoda?via=u42d4986) **[View on Scrimba](https://scrimba.com/build-a-mobile-app-with-firebase-c0g?via=u42d4986)** ## Challenge-first, in the right order, with one big overlap The course does one thing and does it in the right order. Every concept shows up because the shopping list needs it: you need `push` to save an item, `onValue` to see it again after a refresh, `Object.values` to loop over what comes back, a unique ID before you can delete anything, and `createElement` because `innerHTML` strings cannot carry a click handler. Nothing is taught ahead of when you use it, which makes the two hours feel short. The teaching style is challenge-first. In most scrims Rafid writes the task as a comment, says "pause here, try it out for yourself and I'll be right back," and then solves it on screen. I counted challenges in 20 of the 38 scrims, plus the solo project, and some scrims have three in a row. You cannot get through this course by watching. Two things to know before you pay. First, the material dates from early 2023: the Firebase library (the SDK) is pinned to version 9.15.0 and a console timestamp in one lesson reads 2023-01-31. The functions still work in 2026, but the Firebase console screenshots in the slides will not match what you see. Second, the Learn JavaScript overlap covered above is the real limit. This standalone version adds click-to-delete with `Object.entries` and `createElement`, more asides (flexbox, `user-select`) and a solo project, but if you have already done that module, you have seen most of the Firebase side of this. The other limits are small. It is one project and six functions, and security rules get two minutes and a promise of a future course. Rafid also warns that the preview shows a blank page on your side until you paste in your own database URL, so budget a few minutes for that the first time. What the course does well is the rest of the list above: the bugs are real and shown on screen (the duplicated list, the null snapshot, the missing `type="module"`), the solo project is a genuine test of whether you can do it without him, and the last quarter delivers something you can show people on your phone. Verdict: worth it as a first backend if you have not done that module, optional if you have. ## Eight stages from skeleton to installed app Scrimba lists the 38 scrims flat, with no module headings. The groupings below are mine, so you can see where the time goes; durations are the sum of the scrim timers in each group. ### Course curriculum 8 modules ยท 38 lessons - Module 1: Getting set up (12 min, 3 lessons) - Module 2: Connecting Firebase (17 min, 3 lessons) - Module 3: Reading data in realtime (31 min, 7 lessons) - Module 4: Styling the list (7 min, 3 lessons) - Module 5: Deleting items (23 min, 5 lessons) - Module 6: Making it feel like a mobile app (15 min, 9 lessons) - Module 7: Deploy, install, share (11 min, 5 lessons) - Module 8: Solo project and wrap-up (7 min, 3 lessons) I counted 38 scrims on the course page in September 2026, adding up to 2 hours 3 minutes of video; Scrimba's listing and its structured data say 39 lessons, which I take to include the certificate entry that is not a scrim. ## Shopping list, delete-on-click, then the phone install ### 1. Getting set up (12 min, 3 scrims) ![Title slide of Scrimba's Build a Mobile App with Firebase course, reading Mobile App with Firebase, with Rafid Hoda, next to an illustrated instructor](https://scrimbaguide.tech/img/scrimba/build-a-mobile-app-with-firebase/course-intro-title-card.webp) *This module sets expectations, then has you log an input's value and copy a finished CSS design for the Add to Cart shell.* Title card from scrimba.com. The intro scrim is the pitch: you are cooking, you are out of an ingredient, you cannot remember what else you needed. The app is called Add to Cart. Rafid is upfront in the first two minutes that "what we'll be building is not technically a native mobile app. It's a web app that's disguised as a mobile app," and he tells you to go do the free HTML and CSS and JavaScript courses first if you cannot build a form on your own. Scrim 2 hands you an input and a button and asks you to log the input's value on click, which is the level the course starts at. Scrim 3 is a CSS challenge with a finished design to copy: a 320px column, a cat image, a rounded input and a red button. Both of these scrims are free previews. ### 2. Connecting Firebase (17 min, 3 scrims) Scrim 4 is the ten-minute aside where the database arrives, and it is the most important scrim in the course. Rafid walks through the Firebase console: create a project, skip Analytics, create a Realtime Database, pick a region, start in test mode, copy the database URL. Then he explains ES module `import` and `export` from scratch with a tiny `add` function, because that is how the Firebase SDK is loaded. The `Cannot use import statement outside of module` error is shown on purpose so you learn to add `type="module"` to the script tag. Then `initializeApp`, `getDatabase`, `ref` and `push` go in one by one and three movie titles land in the database. He is strict about one thing, and repeats it in scrim 5: "you need to make sure that this is replaced with your specific database URL. Otherwise you will be writing to my database." Scrim 5 makes you redo the whole setup for the shopping list as a challenge. Scrim 6 covers security rules in two and a half minutes: test mode expires after 30 days, so you set read and write to `true`, and Rafid admits that "literally anyone can write to your database" and moves on. ### 3. Reading data in realtime (31 min, 7 scrims) The next half hour is where the app becomes an app. Scrim 7 appends items to a `