Models and pricing
Every model is billed per unit in credits. Failed calls cost nothing, and credits do not expire.
Price list
| Model | Billed item | Unit | Credits | Pool | Licence |
|---|---|---|---|---|---|
| Segmentation | |||||
| SAM 3 sam3 | Image encoding Charged once per call. Waived while the encoding of the same image is still cached for the account; cached encodings are kept for at most 7 days and may be dropped earlier. | per image | 0.5 credits / image ≈ US$0.0005 top-up | Paid | SAM License |
| Text prompt Each text phrase in POST /v1/segment. Exemplar boxes add no charge; a request with exemplar boxes but no text prompt is billed as one prompt. | per text prompt | 0.05 credits / text prompt ≈ US$0.00005 top-up | |||
| Point prompt Each point in POST /v1/segment. | per point | 0.02 credits / point ≈ US$0.00002 top-up | |||
| Refinement Each POST /v1/refine call: one decode, whatever the number of points and whether a box is given. | per refinement | 0.02 credits / refinement ≈ US$0.00002 top-up | |||
| SAM 2.1 Hiera-S sam-lite | Image encoding Charged once per call. Waived while the encoding of the same image is still cached for the account; cached encodings are kept for at most 7 days and may be dropped earlier. | per image | 0.2 credits / image ≈ US$0.0002 top-up | Free | Apache 2.0 |
| Point or box prompt Each point or box in POST /v1/segment. | per point or box | 0.01 credits / point or box ≈ US$0.00001 top-up | |||
| Refinement Each POST /v1/refine call: one decode, whatever the number of points and whether a box is given. | per refinement | 0.01 credits / refinement ≈ US$0.00001 top-up | |||
| Text and documents | |||||
| PP-OCRv6 ppocr-v6 | Text recognition One image per request. | per image | 0.25 credits / image ≈ US$0.00025 top-up | Public | Apache 2.0 |
| PaddleOCR-VL paddleocr-vl | Document parsing One page image per request. | per page | 2 credits / page ≈ US$0.002 top-up | Paid | Apache 2.0 |
| Embeddings | |||||
| DINOv3 dinov3 | Image embedding One image per request. | per image | 0.05 credits / image ≈ US$0.00005 top-up | Public | DINOv3 License Built with DINOv3 |
| SigLIP 2 siglip2 | Image embedding One image per request. | per image | 0.05 credits / image ≈ US$0.00005 top-up | Public | Apache 2.0 |
| Text embedding Each string in texts[]. | per text input | 0.01 credits / text input ≈ US$0.00001 top-up | |||
| Background removal | |||||
| BiRefNet birefnet | Background removal One image per request. | per image | 1 credit / image ≈ US$0.001 top-up | Paid | MIT |
SAM image encoding is charged once per call and waived while the same image is still cached for the account. Cached encodings are kept for at most 7 days and may be dropped earlier, so estimates should include the fee. US$ figures in grey are the equivalent top-up amount at US$1 = 1,000 credits.
Price calculator
Monthly credits for one model at a given volume, computed from the price list.
| Billed item | Quantity | Credits |
|---|---|---|
| Image encoding × 0.5 | 1,000 | 500 |
| Text prompt × 0.05 | 2,000 | 100 |
| Point prompt × 0.02 | 0 | 0 |
| Refinement × 0.02 | 0 | 0 |
| Billed item | Quantity | Credits |
|---|---|---|
| Image encoding × 0.2 | 1,000 | 200 |
| Point or box prompt × 0.01 | 1,000 | 10 |
| Refinement × 0.01 | 0 | 0 |
| Billed item | Quantity | Credits |
|---|---|---|
| Text recognition × 0.25 | 1,000 | 250 |
| Billed item | Quantity | Credits |
|---|---|---|
| Document parsing × 2 | 1,000 | 2,000 |
| Billed item | Quantity | Credits |
|---|---|---|
| Image embedding × 0.05 | 1,000 | 50 |
| Billed item | Quantity | Credits |
|---|---|---|
| Image embedding × 0.05 | 1,000 | 50 |
| Text embedding × 0.01 | 1,000 | 10 |
| Billed item | Quantity | Credits |
|---|---|---|
| Background removal × 1 | 1,000 | 1,000 |
List prices. Included daily calls of the public and free pools are not deducted.
| Model | Call | Credits |
|---|---|---|
| sam3 | 1 image, 1 text prompt 0.5 + 0.05 | 0.55 ≈ US$0.00055 top-up |
| sam3 | 1,000 images, 2 text prompts each 1,000 × (0.5 + 2 × 0.05) | 600 ≈ US$0.60 top-up |
| sam-lite | 1 image, 1 point 0.2 + 0.01 | 0.21 ≈ US$0.00021 top-up |
| sam-lite | 1,000 images, 1 point each 1,000 × (0.2 + 0.01) | 210 ≈ US$0.21 top-up |
| ppocr-v6 | 1 image 0.25 | 0.25 ≈ US$0.00025 top-up |
| ppocr-v6 | 1,000 images 1,000 × 0.25 | 250 ≈ US$0.25 top-up |
| paddleocr-vl | 1 page 2 | 2 ≈ US$0.002 top-up |
| paddleocr-vl | 1,000 pages 1,000 × 2 | 2000 ≈ US$2.00 top-up |
| dinov3 | 1 image 0.05 | 0.05 ≈ US$0.00005 top-up |
| dinov3 | 1,000 images 1,000 × 0.05 | 50 ≈ US$0.05 top-up |
| siglip2 | 1 image 0.05 | 0.05 ≈ US$0.00005 top-up |
| siglip2 | 1,000 images 1,000 × 0.05 | 50 ≈ US$0.05 top-up |
| siglip2 | 1,000 texts 1,000 × 0.01 | 10 ≈ US$0.01 top-up |
| birefnet | 1 image 1 | 1 ≈ US$0.001 top-up |
| birefnet | 1,000 images 1,000 × 1 | 1000 ≈ US$1.00 top-up |
SAM examples assume no cache hit.
Model pools
| Pool | When available | Models | Daily calls | Per minute | Beyond the limit |
|---|---|---|---|---|---|
| Public | After sign-up | ppocr-v6, dinov3, siglip2 | 100 | 10 | Refused with 429 daily_limit_reached until 00:00 UTC. |
| Free | After the first top-up | The public models and sam-lite | 1,000 | 60 | Billed from the balance at the unit prices. |
| Paid | With a balance | All models; sam3, paddleocr-vl and birefnet only here | Not applicable | No fixed limit | Every call is billed from the balance. |
Credits and top-ups
- Top-up rate
- Top-ups are credited at US$1 = 1,000 credits
- Minimum top-up
- US$0.99
- Expiry
- Credits do not expire
- Monthly free credits
- None
- Failed calls
- Not charged
Frequently asked questions
What is a credit?
Credits are the billing unit of Foldbun Stack. Prices, the balance and the cost of every call are stated in credits. Top-ups are credited at US$1 = 1,000 credits.
Do credits expire?
No. Credits stay on the balance until they are spent.
Is there a free tier?
Accounts can call the public model pool (ppocr-v6, dinov3, siglip2) right after sign-up, 100 calls per day. After the first top-up the free pool adds sam-lite with 1,000 calls per day at no charge. There are no monthly free credits.
How are top-ups made?
Online top-up isn't available yet. Top-ups are arranged through support; the console shows how to contact support and the account ID to quote. The minimum top-up is US$0.99.
Is the SAM encoding fee charged on every call?
The encoding fee is charged once per SAM call. When the encoding of the same image is still cached for the account, the fee is waived and the response says "cache": "hit" with "imageFee": 0. Cached encodings are deleted after at most 7 days, and may be dropped earlier.
Which images are accepted?
JPEG, PNG and static WebP, up to 20 MiB and 40 megapixels, sent as base64 or as an img_ handle from an earlier response.
Foldbun Stack — pay-per-use vision model API
Sign in with Foldbun ID to create an API key. The public model pool is available right away.