MQLens
Visual explain plans

See exactly what your MongoDB query does. Explain plans as a visual tree.

Raw explain() output is a deeply nested JSON blob. MQLens renders the winning plan as a readable tree for both find and aggregate — so index usage, COLLSCANs, in-memory sorts, and query stages are easier to follow.

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

MQLens explain plan with stages and sample execution statistics
Step by step

Read an explain plan

  1. Run your query

    Enter a find filter or build an aggregation pipeline.

  2. Open the explain view

    Choose Run Explain from the Run dropdown, or open the Explain Plan tab.

  3. Spot the problem

    Follow scans and sorts in the visual tree, then switch to Raw JSON to compare documents examined and returned.

  4. Add the right index

    Create indexes from the GUI with real key patterns and unique / sparse flags, then re-explain to confirm the win.

Why MQLens

Tune queries without leaving the GUI

Find + aggregate explain

Visual plan tree for both query types, not just a JSON dump.

Index management

Create, inspect, and drop indexes with real key patterns and unique/sparse flags.

Embedded mongosh

A real shell wired to your connection for the moments a GUI can’t reach.

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