FLUX 3 Text to Image

Black Forest Labsimagelive~46s

Text to image up to 4K with bounding-box layout control.

from$0.059/ image

Exact price on the Run button. Failed runs cost $0.00.

How this model is billed

Reserved, then settled to the cent. A failed run costs $0.00.

Typical run ~46s: the measured mean, end to end.

Compare every price

Run FLUX 3 Text to Image

FLUX 3 Text to Image API

Async: the POST answers at once with a request id. Poll it, or take the webhook.

Docs

Submit

Parameters at the top level of the JSON body. Answers 202 with a request id.

curlPOST /v1/models/flux-3-text-to-image

curl -X POST https://api.ezflows.io/v1/models/flux-3-text-to-image \
  -H "Authorization: Bearer $EZFLOWS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "Top-down flat-lay on a reclaimed-wood workbench, four components arranged in a clean grid with even daylight: a disassembled brass pocket-watch movement <watch>, a tight coil of bright copper wire <wire>, a teal printed circuit board <board>, and a fan of red-handled jeweler'\''s screwdrivers <drivers>, with a small white index card <label> in the centre. [{\"id\": \"watch\", \"bbox\": [60, 60, 470, 470], \"desc\": \"disassembled brass pocket-watch movement with exposed gears\"}, {\"id\": \"wire\", \"bbox\": [60, 530, 470, 940], \"desc\": \"tightly wound coil of bright copper wire\"}, {\"id\": \"board\", \"bbox\": [530, 60, 940, 470], \"desc\": \"teal printed circuit board with silver solder points\"}, {\"id\": \"drivers\", \"bbox\": [530, 530, 940, 940], \"desc\": \"fan of six red-handled jeweler'\''s screwdrivers\"}, {\"id\": \"label\", \"bbox\": [420, 300, 580, 700], \"desc\": \"a small white index card with the handwritten words BENCH KIT No. 3\"}]",
    "resolution": "1k",
    "aspect_ratio": "auto"
  }'

# 202 Accepted, at once — it never waits for the model:
# {"request_id": "req_8f2a41c9b70e4d15", "status": "queued",
#  "poll_url": "https://api.ezflows.io/v1/requests/req_8f2a41c9b70e4d15"}

Poll

Same bearer header, every few seconds, until the status is final.

curlGET /v1/requests/:id

REQUEST_ID=req_8f2a41c9b70e4d15   # from the POST

while :; do
  BODY=$(curl -s https://api.ezflows.io/v1/requests/$REQUEST_ID \
    -H "Authorization: Bearer $EZFLOWS_API_KEY")
  STATUS=$(echo "$BODY" | jq -r .data.status)
  case "$STATUS" in succeeded|failed|cancelled) break ;; esac
  sleep 3
done

echo "$BODY" | jq -r '.data.output.artifacts[].url'   # media.ezflows.io, kept 90 days

Response

Files are on media.ezflows.io, kept 90 days. A failed run says why and costs nothing.

json200 · succeeded

{
  "data": {
    "id": "req_8f2a41c9b70e4d15",
    "model_slug": "flux-3-text-to-image",
    "status": "succeeded",
    "http_status": 200,
    "cost": 0.05863,
    "auth_method": "api_key",
    "error": null,
    "submitted_at": "2026-09-12T18:07:21.114Z",
    "queue_started_at": "2026-09-12T18:07:21.402Z",
    "execution_started_at": "2026-09-12T18:07:22.010Z",
    "first_byte_at": "2026-09-12T18:07:52.871Z",
    "finished_at": "2026-09-12T18:07:55.203Z",
    "io_deleted_at": null,
    "canvas_id": null,
    "canvas_node_id": null,
    "client_attempt_id": null,
    "idempotency_key": null,
    "input": {
      "prompt": "Top-down flat-lay on a reclaimed-wood workbench, four components arranged in a clean grid with even daylight: a disassembled brass pocket-watch movement <watch>, a tight coil of bright copper wire <wire>, a teal printed circuit board <board>, and a fan of red-handled jeweler's screwdrivers <drivers>, with a small white index card <label> in the centre. [{\"id\": \"watch\", \"bbox\": [60, 60, 470, 470], \"desc\": \"disassembled brass pocket-watch movement with exposed gears\"}, {\"id\": \"wire\", \"bbox\": [60, 530, 470, 940], \"desc\": \"tightly wound coil of bright copper wire\"}, {\"id\": \"board\", \"bbox\": [530, 60, 940, 470], \"desc\": \"teal printed circuit board with silver solder points\"}, {\"id\": \"drivers\", \"bbox\": [530, 530, 940, 940], \"desc\": \"fan of six red-handled jeweler's screwdrivers\"}, {\"id\": \"label\", \"bbox\": [420, 300, 580, 700], \"desc\": \"a small white index card with the handwritten words BENCH KIT No. 3\"}]",
      "resolution": "1k",
      "aspect_ratio": "auto"
    },
    "output": {
      "artifacts": [
        {
          "index": 0,
          "kind": "image",
          "contentType": "image/png",
          "url": "https://media.ezflows.io/outputs/<account>/req_8f2a41c9b70e4d15/0.png"
        }
      ]
    }
  }
}

Webhook

Skip polling: we POST the result to your endpoint, at least once.

Register: Create an endpoint under Webhooks in the dashboard; the signing secret is shown once.
Events: request.succeeded · request.failed · request.cancelled
Headers: ezflows-event-id (dedupe on it) · ezflows-timestamp (unix seconds) · ezflows-signature t=<ts>,v1=<hex HMAC-SHA256 of "<ts>.<raw body>">
Verify: Over the exact bytes received, in constant time; reject anything older than five minutes.
Respond: Any 2xx within 10 s. Redirects are not followed.
Retries: Five, with backoff: 30 s · 60 s · 2 min · 4 min · 8 min. Disabled after five consecutive dead deliveries.

jsonDelivery body

{
  "id": "82cf46a4-841e-41d6-b3c7-facc937d3252",
  "type": "request.succeeded",
  "created_at": "2026-09-12T18:07:55Z",
  "data": {
    "id": "req_8f2a41c9b70e4d15",
    "model_slug": "flux-3-text-to-image",
    "status": "succeeded",
    "cost": 0.05863,
    "output": {
      "artifacts": [
        {
          "url": "https://media.ezflows.io/…/0.png"
        }
      ]
    }
  }
}

curlverify.sh

# Create the endpoint under Webhooks in the dashboard; the signing secret is shown once.
# ezflows-signature: t=<ts>,v1=<hex HMAC-SHA256 of "<ts>.<raw body>">
# body.json = the exact bytes received. Reject anything older than five minutes.
EXPECTED=$({ printf '%s.' "$TS"; cat body.json; } \
  | openssl dgst -sha256 -hmac "$EZFLOWS_WEBHOOK_SECRET" -r | cut -d' ' -f1)

[ "$EXPECTED" = "$V1" ] && echo "valid" || echo "reject"

Parameters 5

Name	Type	Default	Allowed	Description
promptrequired	string	Top-down flat-lay on a reclaimed-wood workbench, four components arranged in a clean grid with even daylight: a disassembled brass pocket-watch movement <watch>, a tight coil of bright copper wire <wire>, a teal printed circuit board <board>, and a fan of red-handled jeweler's screwdrivers <drivers>, with a small white index card <label> in the centre. [{"id": "watch", "bbox": [60, 60, 470, 470], "desc": "disassembled brass pocket-watch movement with exposed gears"}, {"id": "wire", "bbox": [60, 530, 470, 940], "desc": "tightly wound coil of bright copper wire"}, {"id": "board", "bbox": [530, 60, 940, 470], "desc": "teal printed circuit board with silver solder points"}, {"id": "drivers", "bbox": [530, 530, 940, 940], "desc": "fan of six red-handled jeweler's screwdrivers"}, {"id": "label", "bbox": [420, 300, 580, 700], "desc": "a small white index card with the handwritten words BENCH KIT No. 3"}]	—	Describe subject, composition, lighting and style. Supports bounding-box layouts: tag elements with <id> and append a JSON array of {id, bbox:[y_min,x_min,y_max,x_max] on a 0-1000 grid, desc}.
resolution	enum	1k	768sq · 1k · 1.5k · 2k · 4k	Output size tier (equal pixel area; exact dimensions follow the aspect ratio). Price scales with the tier.
aspect_ratio	enum	auto	auto · 21:9 · 2:1 · 16:9 · 3:2 · 7:5 · 4:3 · 5:4 · 1:1 · 4:5 · 3:4 · 5:7 · 2:3 · 9:16 · 1:2 · 9:21	auto lets the prompt decide, else 1:1. Pick a fixed ratio for a known canvas.
safety_tolerance	integer	2	0–4	Input and output moderation level: 0 is strictest, 4 most permissive.
grounding	boolean	true	—	Let the model ground the prompt in web and image search (real places, products, people in the news). Off for pure imagination.