How MyMemory finds things you only half remember: hybrid search explained
Why keyword search fails on personal libraries, and how combining meaning-based vector search with full-text ranking and date awareness fixes it.
· 1 min read
Quick answer
MyMemory runs two searches at once, one that matches meaning (vector embeddings) and one that matches exact words (full-text ranking), then merges the results and can take dates into account. That's why a vague description finds the right save and an exact quote does too.
You rarely remember the exact title of something you saved. You remember roughly what it was about, maybe a phrase, maybe when you saw it. Good personal search has to work with all three.
Keyword search alone isn't enough
Classic search matches words. Search "cheap dinner ideas" and a recipe titled "5-ingredient weeknight pasta" never shows up: none of the words overlap.
Meaning search alone isn't enough either
Vector (semantic) search turns text into a list of numbers, an embedding, so that texts with similar meaning land close together. It finds the pasta recipe easily. But it can blur exact details: a product code, a person's name, or a precise quote may rank below things that are merely about the same topic.
Hybrid: both at once
MyMemory runs both searches in parallel and merges them:
- Meaning: each memory is turned into an embedding when you save it, and your question is compared against those embeddings.
- Exact words: a full-text search ranks memories that contain your actual terms.
- Time: phrases like "last month" and explicit date ranges narrow results, and an optional recency bias can favour newer saves.
The candidate queries run at the same time rather than one after another, which keeps search fast even though it's doing several lookups.
Keeping results clean
- Duplicates are caught when you save. A content hash detects the same content saved twice, so copies don't crowd out other results.
- Weak matches are cut. Results that only match on meaning need a similarity of at least 0.65 by default.
What this means for you
You don't need to remember titles or exact wording. Describe what you remember ("the article about sleep and coffee", "that recipe with chickpeas") and add a time hint if you have one ("from last spring"). Search and AI chat both use the same hybrid retrieval, so what works in one works in the other.