Technical profile
What developers should know
What the service is for
Stability describes Ultra as its most advanced hosted text-to-image service, emphasizing prompt understanding, photorealism, typography, complex compositions, lighting, color, and overall visual cohesion. These are provider capability claims, not an independent quality ranking.[1]
API contract
The Ultra endpoint accepts POST requests authenticated with a Stability API key. A prompt is required; output can be returned as image bytes or base64 JSON, and the documented image formats are JPEG, PNG, and WebP.[1]
Operational limits
The platform documents moderation and validation failures as separate HTTP responses and applies API-level rate limits. Applications should treat failed or flagged generations as expected states and should not retry them blindly.[1]
Choose the artifact
Official checkpoints
Use the exact documented model or endpoint identifier and record input assets, parameters, output metadata, and failure states for reproducible media workflows.[1]
Pin the v2beta route and record prompt, seed, output format, and API response metadata in reproducible workflows. Keep the API key outside workflow files and public repositories.[1]