Flux Kontext Text-to-Image
Use the text to image endpoint to create an asynchronous Task.
Overview
Use the text to image endpoint with a supported model. Use the returned Task ID to retrieve its state, or provide callback_url for the deliveries documented below.
Quick start
- Create an API key and set it as RUNAPI_API_KEY.
- Choose a supported model and send a POST request whose body matches that model's schema.
- Store the returned task ID, then poll until a terminal state or handle the callbacks documented below.
Endpoint
- Base URL
https://runapi.ai- API version
v1- Authentication
Authorization: Bearer YOUR_API_TOKEN
Supported models
Open a model page for current pricing, rate limits, and commercial-usage details.
Request schema
Fields and allowed values depend on the selected model. When supplied, callback_url receives the Task deliveries documented below.
flux-kontext-max10 fields
aspect_ratiostringOutput aspect ratio. Default: 16:9.
Allowed values:21:9, 16:9, 4:3, 1:1, 3:4, 9:16
callback_urlstringWebhook URL for async notifications.
enable_prompt_expansionbooleanExpand the prompt with more detail. Default: false.
enable_translationbooleanAuto-translate non-English prompts. Default: true.
modelstringModel slug.
output_formatstringOutput format. Default: jpeg.
Allowed values:jpeg, png
promptstringImage description (English only).
safety_toleranceintegerContent safety threshold. 0-6 for generation, 0-2 for editing. Default: 2.
source_image_urlstringSource image URL for editing mode.
watermarkstringWatermark identifier.
flux-kontext-pro10 fields
aspect_ratiostringOutput aspect ratio. Default: 16:9.
Allowed values:21:9, 16:9, 4:3, 1:1, 3:4, 9:16
callback_urlstringWebhook URL for async notifications.
enable_prompt_expansionbooleanExpand the prompt with more detail. Default: false.
enable_translationbooleanAuto-translate non-English prompts. Default: true.
modelstringModel slug.
output_formatstringOutput format. Default: jpeg.
Allowed values:jpeg, png
promptstringImage description (English only).
safety_toleranceintegerContent safety threshold. 0-6 for generation, 0-2 for editing. Default: 2.
source_image_urlstringSource image URL for editing mode.
watermarkstringWatermark identifier.
Create acceptance
POST /api/v1/flux_kontext/text_to_image
Response schema
{
"properties": {
"billing": {
"properties": {
"refund": {
"oneOf": [
{
"properties": {
"refunded_at": {
"type": "string"
}
},
"required": [
"refunded_at"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"reservation": {
"oneOf": [
{
"properties": {
"amount_cents": {
"type": "integer"
}
},
"required": [
"amount_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"settlement": {
"oneOf": [
{
"properties": {
"amount_micro_cents": {
"type": "integer"
},
"charged_amount_cents": {
"type": "integer"
}
},
"required": [
"charged_amount_cents",
"amount_micro_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
}
},
"required": [
"reservation",
"settlement",
"refund"
],
"type": "object",
"unevaluatedProperties": false
},
"id": {
"type": "string"
},
"status": {
"enum": [
"processing"
],
"type": "string"
},
"task_replayed": {
"type": "boolean"
}
},
"required": [
"id",
"status",
"billing"
],
"type": "object",
"unevaluatedProperties": false
}
Response example
{
"billing": {
"refund": null,
"reservation": null,
"settlement": null
},
"id": "tsk_reference_demo",
"status": "processing"
}
Polling processing
GET /api/v1/flux_kontext/text_to_image/:id
Response schema
{
"properties": {
"billing": {
"properties": {
"refund": {
"oneOf": [
{
"properties": {
"refunded_at": {
"type": "string"
}
},
"required": [
"refunded_at"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"reservation": {
"oneOf": [
{
"properties": {
"amount_cents": {
"type": "integer"
}
},
"required": [
"amount_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"settlement": {
"oneOf": [
{
"properties": {
"amount_micro_cents": {
"type": "integer"
},
"charged_amount_cents": {
"type": "integer"
}
},
"required": [
"charged_amount_cents",
"amount_micro_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
}
},
"required": [
"reservation",
"settlement",
"refund"
],
"type": "object",
"unevaluatedProperties": false
},
"id": {
"type": "string"
},
"status": {
"enum": [
"processing"
],
"type": "string"
}
},
"required": [
"id",
"status",
"billing"
],
"type": "object",
"unevaluatedProperties": false
}
Response example
{
"billing": {
"refund": null,
"reservation": null,
"settlement": null
},
"id": "tsk_reference_demo",
"status": "processing"
}
Polling completed
GET /api/v1/flux_kontext/text_to_image/:id
Response schema
{
"properties": {
"billing": {
"properties": {
"refund": {
"oneOf": [
{
"properties": {
"refunded_at": {
"type": "string"
}
},
"required": [
"refunded_at"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"reservation": {
"oneOf": [
{
"properties": {
"amount_cents": {
"type": "integer"
}
},
"required": [
"amount_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"settlement": {
"oneOf": [
{
"properties": {
"amount_micro_cents": {
"type": "integer"
},
"charged_amount_cents": {
"type": "integer"
}
},
"required": [
"charged_amount_cents",
"amount_micro_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
}
},
"required": [
"reservation",
"settlement",
"refund"
],
"type": "object",
"unevaluatedProperties": false
},
"id": {
"type": "string"
},
"images": {
"items": {
"properties": {
"origin_url": {
"type": "string"
},
"url": {
"type": "string"
}
},
"required": [
"url"
],
"type": "object",
"unevaluatedProperties": false
},
"type": "array"
},
"status": {
"enum": [
"completed"
],
"type": "string"
}
},
"required": [
"id",
"status",
"images",
"billing"
],
"type": "object",
"unevaluatedProperties": false
}
Response example
{
"billing": {
"refund": null,
"reservation": null,
"settlement": null
},
"id": "tsk_reference_demo",
"images": [
{
"origin_url": "https://cdn.runapi.ai/public/samples/image.jpg",
"url": "https://cdn.runapi.ai/public/samples/image.jpg"
}
],
"status": "completed"
}
Polling failed
GET /api/v1/flux_kontext/text_to_image/:id
Response schema
{
"properties": {
"billing": {
"properties": {
"refund": {
"oneOf": [
{
"properties": {
"refunded_at": {
"type": "string"
}
},
"required": [
"refunded_at"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"reservation": {
"oneOf": [
{
"properties": {
"amount_cents": {
"type": "integer"
}
},
"required": [
"amount_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"settlement": {
"oneOf": [
{
"properties": {
"amount_micro_cents": {
"type": "integer"
},
"charged_amount_cents": {
"type": "integer"
}
},
"required": [
"charged_amount_cents",
"amount_micro_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
}
},
"required": [
"reservation",
"settlement",
"refund"
],
"type": "object",
"unevaluatedProperties": false
},
"error": {
"type": "string"
},
"id": {
"type": "string"
},
"status": {
"enum": [
"failed"
],
"type": "string"
}
},
"required": [
"id",
"status",
"error",
"billing"
],
"type": "object",
"unevaluatedProperties": false
}
Response example
{
"billing": {
"refund": null,
"reservation": null,
"settlement": null
},
"error": "Task processing failed.",
"id": "tsk_reference_demo",
"status": "failed"
}
Customer callback: completed
POST callback_url
Response schema
{
"properties": {
"id": {
"type": "string"
},
"images": {
"items": {
"properties": {
"origin_url": {
"type": "string"
},
"url": {
"type": "string"
}
},
"required": [
"url"
],
"type": "object",
"unevaluatedProperties": false
},
"type": "array"
},
"status": {
"enum": [
"completed"
],
"type": "string"
}
},
"required": [
"id",
"status",
"images"
],
"type": "object",
"unevaluatedProperties": false
}
Response example
{
"id": "tsk_reference_demo",
"images": [
{
"origin_url": "https://cdn.runapi.ai/public/samples/image.jpg",
"url": "https://cdn.runapi.ai/public/samples/image.jpg"
}
],
"status": "completed"
}
Customer callback: failed
POST callback_url
Response schema
{
"properties": {
"error": {
"oneOf": [
{
"type": "string"
},
{
"properties": {
"code": {
"type": "string"
},
"message": {
"type": "string"
}
},
"required": [
"code",
"message"
],
"type": "object",
"unevaluatedProperties": false
}
]
},
"id": {
"type": "string"
},
"status": {
"enum": [
"failed"
],
"type": "string"
}
},
"required": [
"id",
"status",
"error"
],
"type": "object",
"unevaluatedProperties": false
}
Response example
{
"error": {
"code": "generation_failed",
"message": "Task processing failed."
},
"id": "tsk_reference_demo",
"status": "failed"
}
Errors
POST /api/v1/flux_kontext/text_to_image
This response has no body.
Errors
GET /api/v1/flux_kontext/text_to_image/:id
This response has no body.
Errors
POST /api/v1/flux_kontext/text_to_image
Response schema
{
"properties": {
"billing": {
"properties": {
"refund": {
"oneOf": [
{
"properties": {
"refunded_at": {
"type": "string"
}
},
"required": [
"refunded_at"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"reservation": {
"oneOf": [
{
"properties": {
"amount_cents": {
"type": "integer"
}
},
"required": [
"amount_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"settlement": {
"oneOf": [
{
"properties": {
"amount_micro_cents": {
"type": "integer"
},
"charged_amount_cents": {
"type": "integer"
}
},
"required": [
"charged_amount_cents",
"amount_micro_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
}
},
"required": [
"reservation",
"settlement",
"refund"
],
"type": "object",
"unevaluatedProperties": false
},
"error": {
"properties": {
"code": {
"type": "string"
},
"message": {
"type": "string"
}
},
"required": [
"code",
"message"
],
"type": "object",
"unevaluatedProperties": false
}
},
"required": [
"error"
],
"type": "object",
"unevaluatedProperties": false
}
Response example
{
"error": {
"code": "model_must_be_one_of_flux-kontext-max_flux-kontext-pro",
"message": "model must be one of: flux-kontext-max, flux-kontext-pro"
}
}
Errors
POST /api/v1/flux_kontext/text_to_image
Response schema
{
"properties": {
"billing": {
"properties": {
"refund": {
"oneOf": [
{
"properties": {
"refunded_at": {
"type": "string"
}
},
"required": [
"refunded_at"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"reservation": {
"oneOf": [
{
"properties": {
"amount_cents": {
"type": "integer"
}
},
"required": [
"amount_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"settlement": {
"oneOf": [
{
"properties": {
"amount_micro_cents": {
"type": "integer"
},
"charged_amount_cents": {
"type": "integer"
}
},
"required": [
"charged_amount_cents",
"amount_micro_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
}
},
"required": [
"reservation",
"settlement",
"refund"
],
"type": "object",
"unevaluatedProperties": false
},
"error": {
"properties": {
"code": {
"type": "string"
},
"message": {
"type": "string"
}
},
"required": [
"code",
"message"
],
"type": "object",
"unevaluatedProperties": false
}
},
"required": [
"error"
],
"type": "object",
"unevaluatedProperties": false
}
Response example
{
"error": {
"code": "insufficient_balance",
"message": "Insufficient balance"
}
}
Errors
POST /api/v1/flux_kontext/text_to_image
Response schema
{
"properties": {
"billing": {
"properties": {
"refund": {
"oneOf": [
{
"properties": {
"refunded_at": {
"type": "string"
}
},
"required": [
"refunded_at"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"reservation": {
"oneOf": [
{
"properties": {
"amount_cents": {
"type": "integer"
}
},
"required": [
"amount_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"settlement": {
"oneOf": [
{
"properties": {
"amount_micro_cents": {
"type": "integer"
},
"charged_amount_cents": {
"type": "integer"
}
},
"required": [
"charged_amount_cents",
"amount_micro_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
}
},
"required": [
"reservation",
"settlement",
"refund"
],
"type": "object",
"unevaluatedProperties": false
},
"error": {
"properties": {
"code": {
"type": "string"
},
"message": {
"type": "string"
}
},
"required": [
"code",
"message"
],
"type": "object",
"unevaluatedProperties": false
}
},
"required": [
"error"
],
"type": "object",
"unevaluatedProperties": false
}
Response example
{
"error": {
"code": "api_token_credit_limit_exceeded",
"message": "API key credit limit exceeded"
}
}
Errors
POST /api/v1/flux_kontext/text_to_image
Response schema
{
"properties": {
"billing": {
"properties": {
"refund": {
"oneOf": [
{
"properties": {
"refunded_at": {
"type": "string"
}
},
"required": [
"refunded_at"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"reservation": {
"oneOf": [
{
"properties": {
"amount_cents": {
"type": "integer"
}
},
"required": [
"amount_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"settlement": {
"oneOf": [
{
"properties": {
"amount_micro_cents": {
"type": "integer"
},
"charged_amount_cents": {
"type": "integer"
}
},
"required": [
"charged_amount_cents",
"amount_micro_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
}
},
"required": [
"reservation",
"settlement",
"refund"
],
"type": "object",
"unevaluatedProperties": false
},
"error": {
"properties": {
"code": {
"type": "string"
},
"message": {
"type": "string"
}
},
"required": [
"code",
"message"
],
"type": "object",
"unevaluatedProperties": false
}
},
"required": [
"error"
],
"type": "object",
"unevaluatedProperties": false
}
Response example
{
"error": {
"code": "request_conflict",
"message": "The request uses features that are not supported for the selected model"
}
}
Errors
POST /api/v1/flux_kontext/text_to_image
Response schema
{
"properties": {
"billing": {
"properties": {
"refund": {
"oneOf": [
{
"properties": {
"refunded_at": {
"type": "string"
}
},
"required": [
"refunded_at"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"reservation": {
"oneOf": [
{
"properties": {
"amount_cents": {
"type": "integer"
}
},
"required": [
"amount_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"settlement": {
"oneOf": [
{
"properties": {
"amount_micro_cents": {
"type": "integer"
},
"charged_amount_cents": {
"type": "integer"
}
},
"required": [
"charged_amount_cents",
"amount_micro_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
}
},
"required": [
"reservation",
"settlement",
"refund"
],
"type": "object",
"unevaluatedProperties": false
},
"error": {
"properties": {
"code": {
"type": "string"
},
"message": {
"type": "string"
}
},
"required": [
"code",
"message"
],
"type": "object",
"unevaluatedProperties": false
}
},
"required": [
"error"
],
"type": "object",
"unevaluatedProperties": false
}
Response example
{
"error": {
"code": "rate_limited",
"message": "Rate limit reached. Please retry later."
}
}
Errors
POST /api/v1/flux_kontext/text_to_image
Response schema
{
"properties": {
"billing": {
"properties": {
"refund": {
"oneOf": [
{
"properties": {
"refunded_at": {
"type": "string"
}
},
"required": [
"refunded_at"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"reservation": {
"oneOf": [
{
"properties": {
"amount_cents": {
"type": "integer"
}
},
"required": [
"amount_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"settlement": {
"oneOf": [
{
"properties": {
"amount_micro_cents": {
"type": "integer"
},
"charged_amount_cents": {
"type": "integer"
}
},
"required": [
"charged_amount_cents",
"amount_micro_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
}
},
"required": [
"reservation",
"settlement",
"refund"
],
"type": "object",
"unevaluatedProperties": false
},
"error": {
"properties": {
"code": {
"type": "string"
},
"message": {
"type": "string"
}
},
"required": [
"code",
"message"
],
"type": "object",
"unevaluatedProperties": false
}
},
"required": [
"error"
],
"type": "object",
"unevaluatedProperties": false
}
Response example
{
"error": {
"code": "service_unavailable",
"message": "Service under maintenance, please try again later"
}
}
Errors
POST /api/v1/flux_kontext/text_to_image
Response schema
{
"properties": {
"billing": {
"properties": {
"refund": {
"oneOf": [
{
"properties": {
"refunded_at": {
"type": "string"
}
},
"required": [
"refunded_at"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"reservation": {
"oneOf": [
{
"properties": {
"amount_cents": {
"type": "integer"
}
},
"required": [
"amount_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"settlement": {
"oneOf": [
{
"properties": {
"amount_micro_cents": {
"type": "integer"
},
"charged_amount_cents": {
"type": "integer"
}
},
"required": [
"charged_amount_cents",
"amount_micro_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
}
},
"required": [
"reservation",
"settlement",
"refund"
],
"type": "object",
"unevaluatedProperties": false
},
"error": {
"properties": {
"code": {
"type": "string"
},
"message": {
"type": "string"
}
},
"required": [
"code",
"message"
],
"type": "object",
"unevaluatedProperties": false
}
},
"required": [
"error"
],
"type": "object",
"unevaluatedProperties": false
}
Response example
{
"billing": {
"refund": null,
"reservation": null,
"settlement": null
},
"error": {
"code": "timeout_error",
"message": "The request timed out"
}
}
Errors
GET /api/v1/flux_kontext/text_to_image/:id
Response schema
{
"properties": {
"billing": {
"properties": {
"refund": {
"oneOf": [
{
"properties": {
"refunded_at": {
"type": "string"
}
},
"required": [
"refunded_at"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"reservation": {
"oneOf": [
{
"properties": {
"amount_cents": {
"type": "integer"
}
},
"required": [
"amount_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
},
"settlement": {
"oneOf": [
{
"properties": {
"amount_micro_cents": {
"type": "integer"
},
"charged_amount_cents": {
"type": "integer"
}
},
"required": [
"charged_amount_cents",
"amount_micro_cents"
],
"type": "object",
"unevaluatedProperties": false
},
{
"enum": [
null
]
}
]
}
},
"required": [
"reservation",
"settlement",
"refund"
],
"type": "object",
"unevaluatedProperties": false
},
"error": {
"properties": {
"code": {
"type": "string"
},
"message": {
"type": "string"
}
},
"required": [
"code",
"message"
],
"type": "object",
"unevaluatedProperties": false
}
},
"required": [
"error"
],
"type": "object",
"unevaluatedProperties": false
}
Response example
{
"error": {
"code": "not_found",
"message": "Task with id 'tsk_reference_demo' not found"
}
}
Generated Code Samples
Use cURL directly, or install an SDK for your language. Each sample submits the validated request shown in this reference.
curl -X POST https://runapi.ai/api/v1/flux_kontext/text_to_image \
-H 'Authorization: Bearer YOUR_API_TOKEN' \
-H 'Content-Type: application/json' \
-d '{"model":"flux-kontext-pro","prompt":"A cobalt vase on white marble."}'
Install
npm install @runapi.ai/flux-kontext
import { FluxKontextClient } from "@runapi.ai/flux-kontext";
const client = new FluxKontextClient({ apiKey: process.env.RUNAPI_API_KEY });
const task = await client.textToImage.create({
"model": "flux-kontext-pro",
"prompt": "A cobalt vase on white marble."
});
Install
pip install runapi-flux-kontext
import os
from runapi.flux_kontext import FluxKontextClient
client = FluxKontextClient(api_key=os.environ["RUNAPI_API_KEY"])
task = client.text_to_image.create(
model="flux-kontext-pro",
prompt="A cobalt vase on white marble."
)
Install
go get github.com/runapi-ai/flux-kontext-sdk/go@latest
package main
import (
"context"
"log"
"os"
"github.com/runapi-ai/core-sdk/go/option"
fluxkontext "github.com/runapi-ai/flux-kontext-sdk/go/fluxkontext"
)
func main() {
client, err := fluxkontext.NewClient(option.WithAPIKey(os.Getenv("RUNAPI_API_KEY")))
if err != nil {
log.Fatal(err)
}
task, err := client.TextToImage.Create(context.Background(), fluxkontext.TextToImageParams{
Model: "flux-kontext-pro",
Prompt: "A cobalt vase on white marble.",
})
if err != nil {
log.Fatal(err)
}
_ = task
}
Install
gem install runapi-flux-kontext
require "runapi/flux_kontext"
client = RunApi::FluxKontext::Client.new(api_key: ENV.fetch("RUNAPI_API_KEY"))
task = client.text_to_image.create(
model: "flux-kontext-pro",
prompt: "A cobalt vase on white marble."
)
Install
implementation("ai.runapi:runapi-flux-kontext")
import ai.runapi.fluxkontext.FluxKontextClient;
import ai.runapi.fluxkontext.types.TextToImageParams;
import ai.runapi.core.polling.TaskCreateResponse;
public final class Example {
public static void main(String[] args) {
FluxKontextClient client = FluxKontextClient.builder()
.apiKey(System.getenv("RUNAPI_API_KEY"))
.build();
TaskCreateResponse task = client.textToImage().create(
TextToImageParams.builder()
.model("flux-kontext-pro")
.prompt("A cobalt vase on white marble.")
.build()
);
}
}
Install
composer require runapi-ai/flux-kontext
<?php
require __DIR__ . '/vendor/autoload.php';
use RunApi\Core\ClientOptions;
use RunApi\FluxKontext\FluxKontextClient;
$client = new FluxKontextClient(new ClientOptions(apiKey: getenv('RUNAPI_API_KEY')));
$task = $client->textToImage->create([
"model" => "flux-kontext-pro",
"prompt" => "A cobalt vase on white marble."
]);