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Source Map Explorer - Free Online Bundle Analyzer Tool | IconVault

Upload a .js.map file and see which sources it contains with approximate byte weights. Free, 100% client-side, nothing is uploaded.

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Source Map Explorer

See what is bloating your JS bundle

5 of 5 free uses left

Drop a .js.map file

Source maps never leave your device

5 of 5 free analyses left - runs fully in your browser, nothing is uploaded.

Source breakdown appears here

Sources are listed by mapping count with approximate byte weights.

About this tool

IconVault's Source Map Explorer shows what is really inside your JavaScript bundle. Drop in a .js.map file and it decodes the VLQ mappings, lists every contained source with its mapping count, and estimates approximate byte weights so you can see which files and libraries are eating your bundle.

Analysis runs 100% in your browser: your source map is never uploaded, so proprietary code stays private. It is free with a searchable, sortable-by-weight source list. Weights are honest estimates from mapping share, not exact byte ranges, and only source map version 3 is supported.

Frequently asked questions

Popular searches

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