Tiny Online Tools logoTiny Online ToolssearchSearch tools…grid_viewAll Tools
Homechevron_rightReverse Engineering Toolschevron_rightSource Map ExplorerSource Map Explorer

Source Map Explorer

Load a .map file and map any generated line and column back to the original file, line and source name it came from.

upload_file

Click to browse or drag & drop files here

Drop a .map file

Accepted: .map,.json

upload_file

Click to browse or drag & drop files here

Drop the generated .js file

Accepted: .js,.mjs,.cjs

infoLoad a .map file to get started. Adding the generated .js file it describes lets you see the exact code around any position you look up.

Similar Tools

Source Map Size Analyzer

Source Map Size Analyzer

Attribute a bundle's bytes to the original source files and folders that produced them, using its .map file — see what is actually taking up space.

PBR Texture Tool

PBR Texture Tool

Generate and repair PBR texture maps in your browser, free and with nothing uploaded.

Universal Binary Inspector

Universal Binary Inspector

Drop in any file and automatically detect whether it's an ELF, PE/EXE, Mach-O or WebAssembly binary, then see its key structure at a glance.

Universal Office File Inspector

Universal Office File Inspector

Open DOCX, XLSX, PPTX, ODT, XPS, MHTML, CHM and Publisher files and inspect their parts, relationships and metadata in your browser.

Split PDF

Split PDF

Split a PDF file into individual pages or page ranges.

HTML Minifier

HTML Minifier

Minify HTML by removing comments, whitespace, and redundant attributes.

GLTF & GLB Validator

GLTF & GLB Validator

Validate GLB and GLTF files against the Khronos glTF 2.0 specification and see every error and warning.

apps

More Tools

Browse our full collection of free online tools.

What a source map actually records

A .map file does not contain your original code. Almost always it contains one thing only: a compact table of positions — "generated line 2, column 4110 came from app.js line 88, column 12, and the identifier there was called total." Some maps go further and embed the original file's full text too (sourcesContent), but that field is optional, and plenty of production maps — including, as it happens, jQuery's own — ship without it.

This tool reads that table directly, in your browser, so you can check it against reality instead of trusting a build tool's claim about what it emitted.

What you can do here

  • Load a .map file. You'll immediately see every original source path it lists, laid out as a tree, and a count of how many mappings the map carries.
  • Add the generated .js file it belongs to (optional, but worth it). With it present, a line/column lookup also shows you the exact generated code around the position you queried, and clicking a line in that snippet fills the line field for you.
  • Look up any generated position. Line numbers are 1-based and columns are 0-based, matching the source map specification exactly — the same convention Chrome DevTools and every JS tool uses internally. Not every byte in a bundle is mapped: runtime glue code, module-wrapper boilerplate and minifier output between tokens often have no mapping at all, and this tool says so plainly rather than guessing.
  • Read the original source, when it's there. Click any file in the tree to see its embedded sourcesContent. When a source has no embedded text — the mapping exists, but not the text — you'll see an explicit notice instead of an empty panel pretending there was nothing to show.

Why this matters

Source maps are what turns a stack trace pointing at bundle.min.js:2:184031 into one pointing at src/components/Cart.jsx:41. When that translation looks wrong — an error reported at a line that makes no sense, a debugger stepping into the wrong file — the fastest way to find out whether the map is broken or your mental model is, is to ask the map directly. That's what this does.

Privacy

Both files are parsed entirely in your browser. Nothing is uploaded anywhere.