Welder is a free, open-source, node-based compositor. It works in 32-bit float linear with OpenColorIO and ACES, runs OpenFX plug-ins, and opens your .nk scripts. Roto, paint, keying, tracking and 3D are all in the box.
Every image is 32-bit float, premultiplied, with any number of channels and layers. Renders are pulled through the graph in 256-pixel tiles, on every core, and only for what's on screen.
depth.ZThe classic layout and hotkeys: viewer, node graph, properties bin, curve editor and dope sheet. B is Blur in the graph and the blue channel in the viewer.
Bezier, B-spline, ellipse and rectangle shapes with per-point feather. Open splines with width and feather per point. Clone, reveal, repair and grain-matched paint, with strokes previewed live and tracked to the plate.
RotoRotoPaintScreen keying, IBK, chroma and luminance keyers, despill, and Cryptomatte with objects picked straight from the viewer.
ScreenKeyerIBKColourIBKGimmeChromaKeyerDespillCryptomattePoint tracks for match-moves and stabilising, planar tracking for screens and signs, and an automatic 3D camera tracker that solves lens distortion with the camera.
TrackerPlanarTrackerCameraTrackerCards, cameras, OBJ geometry, projections and a scanline renderer with motion blur. Gaussian splats. Render through your own Blender, with passes coming back as channels.
ScanlineRenderProject3DBlenderRenderSplatRenderOptical-flow retimes and RIFE frame interpolation. Depth-layered defocus with real bokeh, vector blur, and an exponential glow.
OFlowRIFEZDefocusVectorBlurExpoGlowMattes without a green screen, click-to-track masks, depth, and reconstruction, on an NVIDIA GPU. Models download the first time you use them.
AlphaGenTrackMaskDepthReconstructLTXReal shots in the current beta. Switch views with the buttons, or press 1–5 like viewer slots in the app.
Welder opens .nk scripts and writes them back. A command-line renderer handles batch and farm work.
# open a comp, or a .nk script $ welder_ui shot.nk # render every Write node, frames 1001–1100 $ welder render shot.weld -f 1001-1100 # render any one node to a file $ welder node shot.weld Grade1 -o grade.exr # and back out to .nk $ welder nk shot.weld -o shot.nk
Welder is free and open source under the AGPL-3.0. Get it from GitHub at no cost, or through Gumroad, where you can pay what you want to support development.
| Platform | Files | Needs |
|---|---|---|
| Windows 10 / 11 | welder-0.1.3-win64.zipOptional: -python.zip for .nk import, -rife-models.zip for RIFE |
OpenGL 3.3 GPU. Vulkan for GPU nodes and RIFE. |
| Linux x86_64 | welder-0.1.3-linux-x86_64.tar.gzOptional: -rife-models.tar.gz |
glibc 2.28 or newer: Rocky, Alma and RHEL 8 / 9, Ubuntu 20.04+, Debian 11+. X11 or XWayland. |
| macOSComing | Apple silicon and Intel builds are in testing. | macOS 11 or newer. |
Pay what you want, including nothing. Every update lands in your Gumroad library.
Get Welder on GumroadWelder.bat../Welder.The Windows build isn't code-signed yet. If Windows warns you, click More info, then Run anyway.
Welder is built by one compositor and given away. If it saves you time on a shot, a donation helps pay for the build machines, test footage and the hours that go into every release.
This is a test build. Try it on real shots, save often, and keep it off deliveries you can't redo. Report bugs on GitHub Issues, or use Help › Report a Bug in Welder. Include the version, your OS and GPU, what you did, and after a crash the newest file from Help › Open Crash Reports Folder.