Runware

Image generation APIs are crowded, but Runware competes on speed and price. Runware is a Stable Diffusion API for developers that generates and edits images inside their own apps, and the company says results come back in under a second.

That speed comes from custom hardware powered by renewable energy.

The model library is large and includes checkpoints from CivitAI, so you are not stuck with a few stock models.

Beyond text to image, Runware handles background removal, upscaling, inpainting and outpainting through the same API.

Typical uses are custom avatars, concept design and any product that needs images generated on demand.

Runware suits teams that want to call image models over an API instead of running their own GPU infrastructure.

If low latency and cost per image matter more to you than a point-and-click studio, it fits.

It is not a consumer design app, so expect to work in code.