Open-source Leonardo.Ai alternatives

ComfyUI is an open-source application for creating images and other media with diffusion models. Instead of a fixed form, you build a workflow as a graph of connected nodes, where each node handles a step such as loading a model, encoding a prompt or sampling. It is written in Python on top of PyTorch and licensed under GPL-3.0.

The project provides a graphical interface, an API and a backend in one package. The modular design means workflows can be saved, shared and extended, and new capabilities are added through additional nodes. Because inference runs locally, users keep control over their models and outputs. The maintainers describe it more broadly as an engine for AI content creation.

The code is maintained by Comfy Org, which also runs the website at comfy.org, and releases are published on GitHub. ComfyUI suits artists, researchers and developers who want fine control over image generation pipelines and are comfortable wiring nodes together rather than using a simple prompt box.

Open Generative AI is a JavaScript application that presents itself as a free, open-source alternative to commercial AI image and video platforms. It bundles a set of generation studios for creating images and video from prompts, and the README advertises access to several hundred models, including well-known image and video model families.

The project promotes itself as unrestricted, with no content filters, no closed ecosystem and no subscription fees for the app itself. The generation is performed through a third-party model API service called MuAPI, which the README also promotes through a white-label offering for people who want to launch their own branded studio. Because the app has no built-in filters, operators who run it are responsible for how it is used and for complying with applicable laws and provider terms.

The code is MIT licensed, and topics tag it as an alternative to Midjourney and Sora-style tools. Community help is available through Discord. Anyone considering it should review what data is sent to external services and what usage costs the underlying API will bill.

InvokeAI, also called Invoke, is a creative engine for Stable Diffusion models aimed at professionals, artists and enthusiasts who want to generate and refine visual media. It runs a locally hosted web server with a React interface, and the project says it also serves as the base for several commercial products. The code is Apache-2.0 licensed, which the README describes as commercially friendly.

You download and install it on compatible hardware using the Launcher, then generate and iterate on images and build workflows. Features include a Unified Canvas for editing, and repository topics list text-to-image, image-to-image, inpainting and outpainting. It runs on Windows, macOS and Linux. Documentation covers installation, updates and tutorials, and the FAQ and Discord server handle common installation problems. Because generation runs locally, results depend on your GPU and the models you load.

Stable Diffusion web UI, created by AUTOMATIC1111, is a browser interface for Stable Diffusion built with the Gradio library. It lets you generate images from text prompts or from existing images on your own hardware, and it has become a common base for community extensions. It is written in Python with PyTorch and released under the AGPL-3.0 license.

The feature list includes txt2img and img2img modes, inpainting and outpainting, color sketch, prompt matrix, a Stable Diffusion upscale mode, loopback processing, X/Y/Z plots for comparing parameters, and textual inversion with multiple embeddings. Prompt syntax lets you weight parts of the text, and the Extras tab bundles face restoration with GFPGAN and CodeFormer plus upscalers such as RealESRGAN, ESRGAN, SwinIR and LDSR. A one-click install script exists, though Python and git must be installed first, and the README mentions support for video cards with 4 GB of memory.

SD.Next is an all-in-one web interface and server application for AI image and video generation. It is built on Stable Diffusion and supports dozens of models, and it is aimed at artists, researchers and hobbyists who want to create, refine, caption, upscale and process media from a single cross-platform application.

Its README lists features such as automatic model download from a list of reference models, automatic detection of models you add yourself and SDNQ, a quantization engine that can cut VRAM use by up to 4x. Balanced Offload shifts load between CPU and GPU memory so larger models fit on modest hardware. SD.Next can also caption and enhance images with more than 25 built-in language and vision models plus taggers, offers image processing and color-grading tools, and is localized into 15 languages.

SD.Next is written in Python with PyTorch and Hugging Face diffusers and is licensed under Apache-2.0. It performs platform-specific detection and tuning at install time, and it runs on your own computer or server.

Stable Diffusion WebUI Forge is a platform layered on top of Stable Diffusion WebUI, which is based on Gradio. Its stated goals are to make development easier, manage resources more effectively, speed up inference and make it simpler to study experimental features. The name comes from Minecraft Forge, and the project aims to become the Forge for SD WebUI.

It is currently based on SD-WebUI 1.10.1, and because the original project has become mostly static, Forge syncs with it about every 90 days or when important fixes land. The documentation highlights support for Flux models in BitsandBytes NF4 and several GGUF quantization formats, including a GPU weight slider, offload and swap controls, and LoRA support. It also covers integrated ControlNet and LayerDiffuse transparent image editing.

Forge is written in Python, licensed under AGPL-3.0, and runs on your own machine. A one-click installation package that bundles git and Python is available. Users coming from the original UI should read the notes on the Gradio 4 interface, such as using the right mouse button to move the canvas.