promptstringrequired
The prompt to generate an image from.
Flux 3 Text to Image
bfl/flux-3/text-to-imageFLUX 3 by Black Forest Labs generates images from a text prompt, with strong prompt adherence and typography at 512px to 4K resolution tiers.
Try the model
Playground
Input
The prompt to generate an image from.
Additional Settings More
Customize your input with more control.
The aspect ratio of the generated image. Allowed values: 21:9, 16:9, 3:2, 4:3, 5:4, 1:1, 4:5, 3:4, 2:3, 9:16.
Output resolution tier. 4k can take several minutes. Allowed values: 512sq, 768sq, 1k, 2k, 4k.
The format of the generated image. Allowed values: jpeg, png.
ResultExample
What would you like to do next?
Examples
Select an example to load its inputs and result into the playground.
- Open result ↗
Input
{ "prompt": "a red bicycle leaning on a brick wall", "resolution": "1k" }
Flux 3 Text to Image
FLUX 3 by Black Forest Labs generates images from a prompt, with strong prompt adherence and typography at resolution tiers from 512px to 4K.
Fields
| Field | Type | Default | Notes |
|---|---|---|---|
prompt | string, required | — | Text instruction. |
aspect_ratio | 21:9 / 16:9 / 3:2 / 4:3 / 5:4 / 1:1 / 4:5 / 3:4 / 2:3 / 9:16 | — | Output shape. |
resolution | 512sq / 768sq / 1k / 2k / 4k | 1k | Size tier; sets the per-image rate. |
output_format | jpeg / png | jpeg | Output file format. |
Billing
BFL's official per-image tiers: $0.041 for the 512 and 768 square tiers, $0.048 at 1K, $0.10 at 2K, $0.607 at 4K.
| Request | 512sq | 1k | 2k | 4k |
|---|---|---|---|---|
| One image | $0.041 | $0.048 | $0.10 | $0.607 |
Failed runs are not charged.
Prompting
- Quote any text that must appear and say where it goes.
Limits
- One output image per request.
Also on SandBase
Other FLUX 3 endpoints: bfl/flux-3/edit, bfl/flux-3/text-to-video, bfl/flux-3/image-to-video.
Start building
Send your first request
Submit this model through the SandBase Unified Run API.
# The quoted heredoc keeps Unicode and shell metacharacters unchanged.
result=$(curl --fail-with-body --silent \
-X POST "https://api.sandbase.ai/v1/run" \
-H "Authorization: Bearer $SANDBASE_API_KEY" \
-H "Content-Type: application/json" \
--data-binary @- <<'SANDBASE_JSON'
{
"model": "bfl/flux-3/text-to-image",
"prompt": "A red fox leaping over a stream in a pine forest, low-angle wildlife photograph.",
"resolution": "1k",
"output_format": "jpeg"
}
SANDBASE_JSON
)
run_id=$(printf '%s' "$result" | jq -r .id)
for attempt in $(seq 1 120); do
status=$(printf '%s' "$result" | jq -r .status)
case "$status" in completed|failed|timeout) break ;; esac
sleep 2
result=$(curl --fail-with-body --silent \
-H "Authorization: Bearer $SANDBASE_API_KEY" \
"https://api.sandbase.ai/v1/run/$run_id")
done
status=$(printf '%s' "$result" | jq -r .status)
[ "$status" = completed ] || { echo "Generation ended: $status" >&2; exit 1; }
printf '%s\n' "$result"2. Authentication
Create a SandBase API key and set it in your server environment. All requests use Bearer authentication.
export SANDBASE_API_KEY="YOUR_API_KEY"Keep the key on your server. Do not expose it in browser code or commit it to a repository.
3. Queue
Submit a request
POST to /v1/run with this model ID and its inputs. The request example above includes submission and polling.
Fetch request status and result
Use the returned run ID to poll until the status is completed, failed or timeout. Read output only after completed.
curl "https://api.sandbase.ai/v1/run/$RUN_ID" \
-H "Authorization: Bearer $SANDBASE_API_KEY"4. Files
Hosted files
Pass a publicly accessible file URL in the model’s image, video or audio field. Supported formats and limits are shown beside each Playground input.
Uploading images
Use the upload or replace control on supported image fields in the Playground. Video URL fields accept a hosted driving video; they do not imply video-upload support.
5. Schema
Input
resolutionstring
Output resolution tier. 4k can take several minutes.
Default: "1k"
Possible values: "512sq", "768sq", "1k", "2k", "4k"
aspect_ratiostring
The aspect ratio of the generated image.
Possible values: "21:9", "16:9", "3:2", "4:3", "5:4", "1:1", "4:5", "3:4", "2:3", "9:16"
output_formatstring
The format of the generated image.
Default: "jpeg"
Possible values: "jpeg", "png"
{
"model": "bfl/flux-3/text-to-image",
"prompt": "A red fox leaping over a stream in a pine forest, low-angle wildlife photograph.",
"resolution": "1k",
"output_format": "jpeg"
}Output
A completed run exposes its result in output. The following is the model’s saved example, not a new generation.
[
{
"source": "Self organization completed prediction",
"source_url": "https://www.sandbase.ai",
"url": "https://static.sandbase.ai/examples/c1e35942-1b8b-4b9b-8cd8-025f92d1a801/output/3a779308-1f70-4c25-90b3-23db1b6765c0.jpg"
}
]