How to Build a Reddit Social Listening Tool with Sentiment Analysis (on Emergent)

In this tutorial, we’ll build a Reddit Social Listening Tool that lets you search conversations across Reddit based on any keyword and instantly understand the tone of the discussion. The app uses the Reddit API to fetch posts in real time and the VADER sentiment analysis library to score each post’s sentiment on a 0–10 scale. For every result, you’ll see the post’s title, subreddit, upvotes, comments, timestamp, and a direct link - along with a generated sentiment score that quickly shows whether the general mood is positive, neutral, or negative.

The app also includes an AI-powered summary button for each post, giving you a short explanation of what the discussion is about without needing to open or read full threads. Users can save keywords they want to track, view past searches, and filter results by date range, sentiment level, or engagement metrics such as upvotes and comment count. Results can also be exported to CSV for reporting, research, or trend review outside the app.

The interface is clean, professional, and fully mobile-responsive, organized into four main areas: Search, Saved Keywords, History, and a simple Dashboard home screen that explains how to use the tool. Authentication is handled through Google Login, ensuring each user has their own private view and search data.

In short, this tool provides a fast way to understand what Reddit is saying about any topic - built end-to-end using natural language prompts on Emergent, without writing code.

Building on Emergent

Building the Reddit Social Listening Tool in Emergent begins with a single detailed prompt. This prompt describes what the app should do, how the user will interact with it, and how the sentiment scoring and summary features should work. Emergent will use this description to automatically create the backend, database, UI screens, navigation flow, authentication system, and integrations.

Here is the exact prompt used:

Build a Reddit Social Listening Tool that lets users search posts across Reddit based on keywords. The tool should display each post’s upvotes, number of comments, subreddit name, timestamp, and a direct link to the post. Each result should include an automatically generated sentiment score on a 0–10 scale, along with a button that allows the user to generate a short AI-powered summary on demand. Users should be able to filter results by date range, sentiment level, and engagement metrics to refine their insights.

Authentication should be handled through Google Login, with each user getting their own private view. Users should be able to save keywords they want to track, view past search history, and revisit previous searches.

The interface should look professional and be fully mobile-responsive. The landing page should highlight what the tool does, and a simple hamburger-style navigation should lead to different areas of the app. The main tabs should include Search, Dashboard, Saved Keywords, and History. Users should also be able to export their results to CSV for external use.

Once you enter this prompt, the agent will begin setting up the app structure.
Before the app can fetch posts, the agent will require Reddit API credentials.

Setting Up the Reddit API in Emergent

When the agent begins building, it will pause and ask for your Reddit credentials. These allow the app to search and retrieve posts securely and reliably from Reddit.

You will see a message like:

Reddit API Credentials Required

I need Reddit API Client ID, Client Secret, and your Reddit username

to enable authenticated requests to the Reddit API.

Follow these steps to generate the credentials:

1. Open the Reddit Apps Page
   Visit: https://www.reddit.com/prefs/apps
   
   

2. Create a New App
   
   

   • Scroll to the bottom and click Create App or Create Another App

   • Under application type, choose script (this is important)

   • Name: Social Listening Tool

   • Description: Keyword tracking and social listening

   • Redirect URI: http://localhost:8001 (or leave blank for script type)
     
     

3. Get Your Credentials

   • Client ID: The short string under the app name

   • Client Secret: The label called secret

   • Your Reddit Username: Used in the API user-agent string
     
     

4. Provide these to the Emergent Agent
   
   

   • Client ID

   • Client Secret

   • Reddit Username

Once entered, the agent will:

• Connect your app to Reddit’s API

• Set up search endpoints for keyword queries

• Store search results and history

• Enable filters (date, sentiment score, upvotes, comments)

• Allow keyword saving and retrieval

No manual coding is required.

Explaining the Prompt (In Simple Terms)

The prompt you provided tells Emergent exactly how the app should behave, what data it needs to pull from Reddit, and how users should interact with it. Let’s break it down into simple, practical pieces.

First, the app needs to be able to search Reddit posts by keyword. When someone enters a keyword like “electric cars”, the app should go to Reddit, find relevant posts, and display useful details: the subreddit they came from, how many upvotes and comments they received, when they were posted, and a link back to Reddit. This gives the user a clear snapshot of what’s being discussed and where the most active conversations are.

Next, the prompt tells Emergent to analyze sentiment. This is where the VADER library comes in. VADER reads the tone of the post text and assigns it a score on a 0–10 scale, where lower means negative sentiment and higher means positive. This allows users to quickly understand the mood of discussions without reading every post.

The app also includes an AI summary button. Instead of opening a Reddit thread and scrolling through hundreds of comments, a user can click “Summarize” and instantly get a short explanation of what the conversation is actually about. This saves time and helps users extract insights faster.

The prompt also specifies filters and personalization. Users can refine search results by date range, sentiment score, upvotes, or comment volume - making it easier to find high-quality or meaningful conversations. They can also save keywords they search often and view past search history, creating a private record of what they’ve been tracking.

Finally, the prompt explains the app’s user experience. It will use Google Login for authentication, so each person has their own private view. The interface should be clean, mobile-responsive, and organized into simple navigation tabs: Search, Saved Keywords, History, and a dashboard-style home screen. Users can also export their data to CSV, which is helpful for reports, research, analysis, or sharing.

Using the App

Once the app is built, the interface is organized into four main sections: Search, Saved Keywords, History, and the Dashboard Home screen. Each area has a clear purpose that supports how users explore Reddit conversations.

The Search page is where everything begins. Users type in a keyword or topic they want to analyze - for example, “EV charging,” “iPhone launches,” or “Ethereum staking.” Once they hit search, the app retrieves relevant Reddit posts and displays them in clean, scrollable result cards. Each card shows the post title, subreddit, upvote count, comment count, timestamp, and a direct link to the post. A sentiment score appears alongside the result, indicating whether the overall tone is positive, neutral, or negative. Users can click the Summarize button on any result to generate a concise, AI-generated explanation of the conversation.

Users can save keywords they want to monitor frequently. When a keyword is saved, it appears on the Saved Keywords page, making it easy to run the same search again without retyping anything. This is useful for brand mentions, ongoing events, emerging trends, or recurring topics of interest.

The History page automatically records previous searches. Each entry includes the keyword, the time of search, and quick access back to the results. This allows users to revisit topics, compare shifts in discussion tone, or maintain research continuity over time.

The Dashboard Home screen acts as a simple, welcoming overview. It briefly explains the purpose of the tool and provides quick links to start searching or view saved items. The interface is clean, mobile-responsive, and designed to feel simple even when dealing with large volumes of conversation data.

This structure keeps the experience focused, organized, and easy to use, whether the goal is research, monitoring, or casual exploration of how Reddit is discussing a topic.

Deploying the App

Once you’re happy with how the Reddit Social Listening Tool looks and behaves in preview mode, you can deploy it so it stays online and can be accessed anytime.

To deploy, click the Deploy button in the top-right corner of your Emergent workspace. Before deployment begins, run the Pre-deployment Health Check. This step confirms that your API connections, authentication flow, and data storage are functioning correctly. Once the check completes successfully, click Start Deployment.

Emergent will handle the deployment automatically. It will package the project, set up the production environment, secure the Reddit and Google authentication credentials, and run final system checks to ensure everything works as expected. When the deployment finishes, you’ll receive a live link to your app - this is the link you can use personally or share with others.

Keeping the app deployed uses 50 credits per month, which allows the servers to stay active and prevents the app from going to sleep. If you want branding, you can also connect a custom domain to the deployment link.

How You Can Improve the App

Once your Reddit Social Listening Tool is live, you can enhance it with new capabilities using small, focused prompts in Emergent. Each improvement can be added without rewriting the app - just describe the feature and the agent will update the backend, UI, and database automatically.

Here are some useful upgrades you can add:

1. Track Comments and Analyze Sentiment at the Comment Level

Right now, sentiment is based on the post text. You can extend this to analyze the top comments to understand how people are reacting.

3-Line Prompt to Add:

Add comment sentiment analysis to each Reddit post. Fetch the top 10 comments for every result and calculate a sentiment score for each. Display the average comment sentiment next to the post score.

2. Add Notifications for Keyword Spikes

If suddenly many new posts appear about a keyword, the user should be notified.

3-Line Prompt to Add:

Add notification alerts for search keywords. If the number of new Reddit posts for a saved keyword increases significantly in a short period, notify the user inside the app.

3. Add Daily or Weekly Email Summaries

Send users a quick digest of what changed around their tracked keywords.

3-Line Prompt to Add:

Add an email summary feature. Once a day or once a week, send users an email summarising new posts, sentiment shifts, and notable discussions for their saved keywords.