BSP Decompiler Online
Turn a compiled Source or GoldSrc map back into editable Hammer source.
How It Works
Detect
The map header and version are read from bytes, so Source and GoldSrc are told apart reliably.
Reconstruct
Source maps go to BSPSource, GoldSrc maps to ericw-tools — brushes, entities and texture axes.
Download
Open the VMF or MAP in Hammer and download any materials, models or textures packed into the map.
Source BSP to VMF, GoldSrc BSP to MAP
Source games compile editable .vmf maps into .bsp files for fast rendering. Counter-Strike: Source and CS:GO, Team Fortress 2, Garry's Mod, Portal, Left 4 Dead and many Half-Life 2 mods all use variants of this format. Compilation discards editor-only structure, so decompilation is a careful reconstruction rather than recovery of the byte-identical original.
What You Get
Source maps:
<mapname>.vmf— editable Hammer map source containing reconstructed world brushes, brush entities, point entities, overlays and displacements.materials/,models/and other asset paths — files extracted from the BSP's embedded pakfile when present.
GoldSrc maps:
<mapname>.map— Valve 220 map source with world brushes, brush entities and point entities.<mapname>.wad— the map's textures, when it was compiled with-nowadtexturesand carries them internally.
Both come with a DECOMPILATION-NOTES.txt recording the detected engine and version, the decompiler used, limitations, and any map-protection or obfuscation markers.
GoldSrc BSP29 and BSP30
Half-Life 1 and Counter-Strike 1.6 maps look similar but use the older GoldSrc format. They have no magic string, so this service only identifies them after validating all 15 lump entries and the entity lump; a random binary beginning with integer 29 or 30 is rejected. They are decompiled with ericw-tools into Valve 220 .map — the format GoldSrc Hammer and J.A.C.K. expect — rather than Source's .vmf, which does not apply to this engine.
GoldSrc maps normally reference external .wad texture files that were never inside the BSP; the recovered worldspawn lists the ones the original author used in its wad key, along with their original build paths.
Map Protection and Accuracy
BSPSource detects common VMEX, BSPProtect and IID anti-decompilation techniques. It still recovers what it can and records the detected method in the notes. Comments, visgroups, exact original brush grouping and some compiler-consumed helper entities cannot be restored because they are not present in the BSP.
Frequently Asked Questions
Will the VMF match the original exactly?
No. The VMF is editable and preserves the compiled geometry and entities as closely as possible, but compiler optimisations erase comments and some construction history.
Are embedded custom textures included?
Yes. The map's pakfile is extracted with its original directory layout, while generated cubemap and patched helper files are skipped.
Why did my GoldSrc map produce a .map instead of a .vmf?
Because that is what GoldSrc Hammer opens. VMF belongs to the Source engine; Half-Life and Counter-Strike 1.6 maps use the older Valve 220 MAP format, and converting between the two is not something a decompiler can do meaningfully.