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Documentation & FAQ

Everything you need to know about Merge.

Guide

How to Create a Blend

Merge now supports two creation paths:

1. Paste Mode (Solo)

Go to Create Blend. Add your own playlists (picker or pasted URLs), then paste your friend's public URLs. No login required for your friend.

2. Invite Mode (Collaborative)

Go to Invite, generate a link, and send it. Your friend opens it on their own device, logs in, connects YouTube Music, then joins.

3. Generate & Export

Click Generate Blend. Merge analyzes your input, finds the overlap, scores compatibility, and builds a balanced playlist. Click Sync to YT Music to push it to your library.

Under the Hood

How the Algorithm Works

Merge builds a playlist in four sections:

  • Shared Taste — tracks in both libraries after normalization and fuzzy matching.
  • From User A / B — unique tracks ranked by overlap ratio, artist similarity, and diversity.
  • New Discoveries — algorithmic radio picks seeded from shared tracks, filtered for novelty.

Limits: 50 tracks total, 20 per section. Compatibility: 2 x |shared| / (|A| + |B|) x 100.

Feedback

Improving Recommendations

Each track shows feedback controls on hover (desktop) or always visible (mobile). Your feedback is stored and influences future blend scoring.

After viewing the playlist you can rate the overall blend (1-5 stars) and leave a quick note. All feedback is optional.

Security

Privacy & Authentication

How does login work?

Merge uses Google OAuth. After login, the backend redirects to the frontend with a short-lived session token. The frontend stores it locally and sends it as Authorization: Bearer on each request.

Do invite links expire?

Yes. Invite links expire in 7 days and can only be joined once.

FAQ

Common Questions

Does this work with Spotify?

No. Merge is built specifically for YouTube Music using ytmusicapi.

How many playlists can I add?

Up to 5 per listener. Each must be a valid YouTube Music playlist URL.

Is there a track limit?

Yes — 50 tracks total, 20 per section.

My blend failed — what gives?

Make sure pasted playlists are Public or Unlisted. In Invite Mode, both users should connect YouTube Music.

Is Merge free?

Yes. Free, open-source, and community-driven. View on GitHub.