MQLens
Schema analysis

Understand your MongoDB schema. Without writing scripts.

MongoDB is schemaless, so the real shape of a collection lives in the data. MQLens samples a collection and reports per-field types, presence / coverage, and nested paths — surfacing mixed types and optional fields you’d otherwise discover the hard way.

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Free & open source (Apache-2.0) · No telemetry · No account.

MQLens schema analysis showing per-field types and coverage
Step by step

Analyze a collection

  1. Open a collection

    Pick the collection whose shape you want to understand.

  2. Run schema analysis

    Choose a sample size and let MQLens scan the documents.

  3. Read types & coverage

    See each field’s types and how often it’s present, including nested paths.

  4. Act on it

    Spot mixed types, missing fields, and stragglers — then add indexes or fix data from the same app.

Why MQLens

See the real shape of your data

Per-field types + coverage

Exactly which types appear in each field, and in what percentage of documents.

Nested paths

Coverage for embedded documents and arrays, not just top-level fields.

Fix what you find

Pairs with visual explain plans and index management to act on the gaps.

Download MQLens — it's free

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Point MQLens at your MongoDB cluster.

Free, open source, native — yours to inspect and run.

Download for free