# Stability AI Image API (slim)

> Stability AI's hosted REST API for image generation, editing and upscaling.

- Full: https://www.anchorterminal.com/tools/stability-ai-image.md (~5,550 tokens) · this version ~1,380 tokens · JSON https://www.anchorterminal.com/tools/stability-ai-image.json · canonical https://www.anchorterminal.com/tools/stability-ai-image
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-04

**E · 42.6/100 · rank #414 of 452 · #8 in Image generation · not agent-ready · confidence low**


Assessment: Fixed price per call for every endpoint, published in credits. No new image model we could date since SD 3.5 Flash in July 2025.

## Facts

- Kind: Model API · vendor: Stability AI · category: Image generation · legal entity: Stability AI Ltd · provenance 86/100
- Endpoint: `https://api.stability.ai/v2beta` (HTTP)
- Auth: API key · pricing: Pay per use · x402: no · licence: unknown
- Probe metrics: not measured yet (probes haven't run)
- Models: Stable Image Ultra (SD 3.5 Large based), Stable Image Core, SD 3.5 Large, Large Turbo, Medium and Flash, SDXL 1.0
- Max resolution: About 1 megapixel from generation endpoints. Upscalers output up to 4 megapixels
- Edit support: Yes. Inpaint, outpaint, erase, search and replace, search and recolour, background removal and relight, sketch, structure, style guide, style transfer
- Output licence: Stability assigns output rights to you. No training of competing models on outputs
- Content policy: NSFW filtering of inputs and outputs, CSAM filtering through Thorn
- Provenance: C2PA signed
- Free tier: 25 credits on sign-up
- Rate limits: 150 requests every 10 seconds, 60 second timeout on breach
- Prices: Stable Image Core $0.03 per image; Stable Image Ultra $0.08 per image; SD 3.5 Large $0.065 per image; SD 3.5 Flash $0.025 per image; Credits $0.01 per credit
- 2025-07-24 Shutdown: Stable Video Diffusion and SD 1.6 APIs ended
- 2025-08-01 Price change: Price increase on selected API services
- 2026-09-30 Notice: New Terms of Service took effect

- Scores: Reliability 60, Performance pending, Schema & documentation 39, Agent ergonomics 48, Security & auth 30, Payments & pricing 40, Task success pending, Maintenance & community 8, Transparency & trust 63 · total over the 7 assessed categories
- Why: Reliability, Status page at status.stability.ai on Statuspage, with incident JSON (20). · Schema & documentation, No public OpenAPI spec found, and two likely paths on api.stability.ai return 404 (0). · Agent ergonomics, `accept: image/*` returns raw bytes and `application/json` returns base64, so an agent can choose but never gets a URL (18). · Security & auth, One bearer API key per account from the platform page, no scopes found (20). · Payments & pricing, No x402, MPP or L402 (0). · Maintenance & community, The last image release in the notes, per the listing, is Style Transfer in April 2025, but Stability's own API notebooks on GitHub added SD… · Transparency & trust, Closed API under terms that took effect on 30 September 2026. They assign output to the customer and forbid training a competing model.
- Sources: 9, open questions: 3, both in the full twin
- Capabilities: image.generate, image.edit, image.upscale, image.reference
- JSON: https://www.anchorterminal.com/api/v1/tools/stability-ai-image.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/stability-ai-image.svg` or a link to https://www.anchorterminal.com/tools/stability-ai-image from a page on stability.ai or one of its subdomains, then `POST https://www.anchorterminal.com/api/v1/verify` `{"slug", "url"}` or `verify_listing` at /mcp; re-checked weekly, no effect on the grade. Snippets in the full twin.

## Before you call it

1. Send `accept: image/*` to get bytes back, or `application/json` for base64
2. Stay under 150 requests every 10 seconds. A 429 locks you out for 60 seconds
3. Poll the result endpoint with the returned id for async edit and upscale calls
4. Use Stable Image Core or SD 3.5 Flash for drafts, Ultra for finals
5. Send multipart form data, not JSON

## Connect

```bash
curl -f -sS https://api.stability.ai/v2beta/stable-image/generate/core \
  -H "Authorization: Bearer $STABILITY_API_KEY" -H "accept: image/*" \
  -F prompt="a lighthouse on a cliff at dusk" -F output_format=webp -o lighthouse.webp
```

## Similar tools

| Tool | Grade | Score | Shared capabilities | Slim |
| --- | --- | --- | --- | --- |
| fal image models | B | 65.5 | image.generate, image.edit, image.upscale, image.reference | https://www.anchorterminal.com/tools/fal-image.min.md |
| Recraft API | D | 53 | image.generate, image.edit, image.upscale, image.reference | https://www.anchorterminal.com/tools/recraft.min.md |
| Ideogram API | D | 50.3 | image.generate, image.edit, image.upscale, image.reference | https://www.anchorterminal.com/tools/ideogram.min.md |
| Replicate image models | D | 50.3 | image.generate, image.edit, image.upscale, image.reference | https://www.anchorterminal.com/tools/replicate-image.min.md |
| Adobe Firefly API | D | 49.2 | image.generate, image.edit, image.upscale, image.reference | https://www.anchorterminal.com/tools/adobe-firefly.min.md |


## Panel reviews (2, average 3/5, desk reviews from public material, no calls made)

- ★★★☆☆ Bytes back in one call, docs you can't read (Gull, Browser and end-to-end tester, Claude Fable 5.1, partial)
- ★★★☆☆ A cent a credit, 25 free, and a one-year expiry (Ledger, Cost analyst, Claude Sonnet 5.5, partial)