How to Build a YouTube Video Summarizer Using Gemini AI and Python: A Beginner’s Guide

from youtube_transcript_api import YouTubeTranscriptApi
import google.generativeai as genai
import re

# ✅ Insert your Gemini API Key here
gemini_api_key = "YOUR_GEMINI_API_KEY_HERE"

# Configure Gemini
genai.configure(api_key=gemini_api_key)

# Extracts video ID from the YouTube URL
def extract_video_id(url):
    pattern = r"(?:v=|\/)([0-9A-Za-z_-]{11}).*"
    match = re.search(pattern, url)
    return match.group(1) if match else None

# Gets the video transcript
def get_transcript(video_id):
    transcript = YouTubeTranscriptApi.get_transcript(video_id)
    full_text = " ".join([item['text'] for item in transcript])
    return full_text

# Sends the transcript to Gemini AI for summarization
def summarize_text(text):
    model = genai.GenerativeModel("gemini-2.0-flash")
    prompt = f"""
    Summarize the following YouTube video transcript into a well-structured summary with bullet points or clear sections, while keeping this short and simple:
    - Key Takeaways
    - Main Points Discussed
    - Conclusion

    Transcript:
    {text}
    """
    response = model.generate_content(prompt)
    return response.text

# Cleans the AI response for neat formatting
def clean_gemini_output(raw_text):
    cleaned = re.sub(r"\*\*(.*?)\*\*", lambda m: m.group(1).upper(), raw_text)
    cleaned = re.sub(r"^\s*\*\s*", "- ", cleaned, flags=re.MULTILINE)
    cleaned = re.sub(r"\*", "", cleaned)
    cleaned = re.sub(r"\n{3,}", "\n\n", cleaned).strip()
    return cleaned

# Main program execution
if __name__ == "__main__":
    youtube_url = input("Enter the YouTube URL: ")
    video_id = extract_video_id(youtube_url)

    if not video_id:
        print("Invalid YouTube URL.")
    else:
        transcript = get_transcript(video_id)
        summary = summarize_text(transcript)
        formatted_summary = clean_gemini_output(summary)

        print("\n📄 Video Summary:\n")
        print(formatted_summary)