Imagen 4 API documentation

Integrate Imagen 4 with your VezAPI key. The operations below share the same authentication and account balance.

Base URL: https://api.vezapi.com
Send Authorization: Bearer YOUR_VEZAPI_KEY. Use a unique Idempotency-Key for each submission; reuse it only when checking the same request.

Google - imagen4-fast

POST/api/v1/jobs/createTask

Model IDs: google/imagen4-fast

Parameter	Type	Description & constraints
`model` required	`string`	The model name to use for generation. Required field. - Must be `google/imagen4-fast` for this endpoint Values: `"google/imagen4-fast"` Default: `"google/imagen4-fast"`
`callBackUrl` optional	`string`	The URL to receive generation task completion updates. Optional but recommended for production use. - System will POST task status and results to this URL when generation completes - Callback includes generated content URLs and task information - Your callback endpoint should accept POST requests with JSON payload containing results - Alternatively, use the Get Task Details endpoint to poll task status - To ensure callback security, see [Webhook Verification Guide](/common-api/webhook-verification) for signature verification implementation
`input` optional	`object`	Input parameters for the generation task
`input.prompt` required	`string`	The text prompt describing what you want to see (Max length: 5000 characters) `maxLength: 5000`
`input.negative_prompt` optional	`string`	A description of what to discourage in the generated images (Max length: 5000 characters) `maxLength: 5000`
`input.aspect_ratio` required	`string`	Required. Aspect ratio of the output image: 1:1, 16:9, 9:16, 3:4, 4:3 or auto. Values: `"1:1", "16:9", "9:16", "3:4", "4:3", "auto"`
`input.seed` optional	`integer`	Random seed for reproducible generation

Request example

curl -X POST 'https://api.vezapi.com/api/v1/jobs/createTask' \
  -H 'Authorization: Bearer YOUR_VEZAPI_KEY' \
  -H 'Idempotency-Key: your-unique-request-id' \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "google/imagen4-fast",
  "input": {
    "prompt": "Create a cinematic, photorealistic medium shot capturing the nostalgic warmth of a late 90s indie film. The focus is a young woman with brightly dyed pink hair (slightly faded) and freckled skin, looking directly and intently into the camera lens with a hopeful yet slightly uncertain smile. She wears an oversized, vintage band t-shirt (slightly worn, with the faintly cracked white text “KIE AI” across the chest) layered over a long-sleeved striped top, along with simple silver stud earrings. The lighting is soft, golden hour sunlight streaming through a slightly dusty window, creating lens flare and illuminating dust motes in the air. The background shows a blurred, cluttered bedroom with posters on the wall and fairy lights, rendered with a shallow depth of field. Natural film grain, a warm, slightly muted color palette, and sharp focus on her expressive eyes enhance the intimate, authentic feel.",
    "aspect_ratio": "16:9"
  }
}'

Responses and errors

HTTP 200

Request successful

Parameter	Type	Description & constraints
`code` optional	`integer`	Status code of the request. The HTTP status is 200 even when the request fails, so always check this field: 200 means success; any other value means the request failed and msg describes the reason. Common values: 401 invalid or missing API key; 402 insufficient credits; 429 rate limit exceeded; 422 or 500 the request could not be processed (read msg and check your parameters before retrying). Values: `200, 401, 402, 404, 422, 429, 433, 455, 500, 501, 505`
`msg` optional	`string`	Response message, error description upon failure
`data` required	`object`
`data.taskId` required	`string`	The task ID can be used with the "Get Task Details" endpoint to query the task status.

HTTP 500

Server error.

Parameter	Type	Description & constraints
`code` required	`integer`	Response status code - 200: Success - Request has been processed successfully - 401: Unauthorized - Authentication credentials are missing or invalid - 402: Insufficient Credits - Account does not have enough credits to perform the operation - 404: Not Found - The requested resource or endpoint does not exist - 408: Timeout - No result has been returned for over 10 minutes. - 422: Validation Error - The request parameters failed validation checks - 429: Rate Limited - Request limit has been exceeded for this resource - 455: Service Unavailable - System is currently undergoing maintenance - 500: Server Error - An unexpected error occurred while processing the request - 501: Generation Failed - Content generation task failed - 505: Feature Disabled - The requested feature is currently disabled
`msg` required	`string`	Response message, error description when failed
`data` required	`object`

Google - imagen4-ultra

POST/api/v1/jobs/createTask

Model IDs: google/imagen4-ultra

Parameter	Type	Description & constraints
`model` required	`string`	The model name to use for generation. Required field. - Must be `google/imagen4-ultra` for this endpoint Values: `"google/imagen4-ultra"` Default: `"google/imagen4-ultra"`
`callBackUrl` optional	`string`	The URL to receive generation task completion updates. Optional but recommended for production use. - System will POST task status and results to this URL when generation completes - Callback includes generated content URLs and task information - Your callback endpoint should accept POST requests with JSON payload containing results - Alternatively, use the Get Task Details endpoint to poll task status - To ensure callback security, see [Webhook Verification Guide](/common-api/webhook-verification) for signature verification implementation
`input` optional	`object`	Input parameters for the generation task
`input.prompt` required	`string`	The text prompt describing what you want to see (Max length: 5000 characters) `maxLength: 5000`
`input.negative_prompt` optional	`string`	A description of what to discourage in the generated images (Max length: 5000 characters) `maxLength: 5000`
`input.aspect_ratio` required	`string`	Required. Aspect ratio of the output image: 1:1, 16:9, 9:16, 3:4, 4:3 or auto. Values: `"1:1", "16:9", "9:16", "3:4", "4:3", "auto"`
`input.seed` optional	`string`	Random seed for reproducible generation (Max length: 500 characters) `maxLength: 500`

Request example

curl -X POST 'https://api.vezapi.com/api/v1/jobs/createTask' \
  -H 'Authorization: Bearer YOUR_VEZAPI_KEY' \
  -H 'Idempotency-Key: your-unique-request-id' \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "google/imagen4-ultra",
  "input": {
    "prompt": "A lively comic scene where two colleagues are in an office. The first person says, '\''Have you heard about Google Imagen 4 Ultra?'\'' The second person responds with excitement, '\''It’s the best text-to-image tool out there!'\'' The first person asks again, '\''Do you know where to get the API?'\'' The second person smiles and says, '\''Kie.ai has it!'\'' In the final panel, the two look at a screen showing Kie.ai’s interface with an API option, with bright and colorful comic-style illustrations.",
    "aspect_ratio": "1:1"
  }
}'

Responses and errors

HTTP 200

Request successful

Parameter	Type	Description & constraints
`code` optional	`integer`	Status code of the request. The HTTP status is 200 even when the request fails, so always check this field: 200 means success; any other value means the request failed and msg describes the reason. Common values: 401 invalid or missing API key; 402 insufficient credits; 429 rate limit exceeded; 422 or 500 the request could not be processed (read msg and check your parameters before retrying). Values: `200, 401, 402, 404, 422, 429, 433, 455, 500, 501, 505`
`msg` optional	`string`	Response message, error description upon failure
`data` required	`object`
`data.taskId` required	`string`	The task ID can be used with the "Get Task Details" endpoint to query the task status.

HTTP 500

Server error.

Parameter	Type	Description & constraints
`code` required	`integer`	Response status code - 200: Success - Request has been processed successfully - 401: Unauthorized - Authentication credentials are missing or invalid - 402: Insufficient Credits - Account does not have enough credits to perform the operation - 404: Not Found - The requested resource or endpoint does not exist - 408: Timeout - No result has been returned for over 10 minutes. - 422: Validation Error - The request parameters failed validation checks - 429: Rate Limited - Request limit has been exceeded for this resource - 455: Service Unavailable - System is currently undergoing maintenance - 500: Server Error - An unexpected error occurred while processing the request - 501: Generation Failed - Content generation task failed - 505: Feature Disabled - The requested feature is currently disabled
`msg` required	`string`	Response message, error description when failed
`data` required	`object`

Google - imagen4

POST/api/v1/jobs/createTask

Model IDs: google/imagen4

Parameter	Type	Description & constraints
`model` required	`string`	The model name to use for generation. Required field. - Must be `google/imagen4` for this endpoint Values: `"google/imagen4"` Default: `"google/imagen4"`
`callBackUrl` optional	`string`	The URL to receive generation task completion updates. Optional but recommended for production use. - System will POST task status and results to this URL when generation completes - Callback includes generated content URLs and task information - Your callback endpoint should accept POST requests with JSON payload containing results - Alternatively, use the Get Task Details endpoint to poll task status - To ensure callback security, see [Webhook Verification Guide](/common-api/webhook-verification) for signature verification implementation
`input` optional	`object`	Input parameters for the generation task
`input.prompt` required	`string`	The text prompt describing what you want to see (Max length: 5000 characters) `maxLength: 5000`
`input.negative_prompt` optional	`string`	A description of what to discourage in the generated images (Max length: 5000 characters) `maxLength: 5000`
`input.aspect_ratio` required	`string`	Required. Aspect ratio of the output image: 1:1, 16:9, 9:16, 3:4, 4:3 or auto. Values: `"1:1", "16:9", "9:16", "3:4", "4:3", "auto"`
`input.seed` optional	`string`	Random seed for reproducible generation (Max length: 500 characters) `maxLength: 500`

Request example

curl -X POST 'https://api.vezapi.com/api/v1/jobs/createTask' \
  -H 'Authorization: Bearer YOUR_VEZAPI_KEY' \
  -H 'Idempotency-Key: your-unique-request-id' \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "google/imagen4",
  "input": {
    "prompt": "A lively comic scene where two colleagues are in an office. The first person says, '\''Have you heard about Google Imagen 4 Ultra?'\'' The second person responds with excitement, '\''It’s the best text-to-image tool out there!'\'' The first person asks again, '\''Do you know where to get the API?'\'' The second person smiles and says, '\''Kie.ai has it!'\'' In the final panel, the two look at a screen showing Kie.ai’s interface with an API option, with bright and colorful comic-style illustrations.",
    "aspect_ratio": "1:1"
  }
}'

Responses and errors

HTTP 200

Request successful

Parameter	Type	Description & constraints
`code` optional	`integer`	Status code of the request. The HTTP status is 200 even when the request fails, so always check this field: 200 means success; any other value means the request failed and msg describes the reason. Common values: 401 invalid or missing API key; 402 insufficient credits; 429 rate limit exceeded; 422 or 500 the request could not be processed (read msg and check your parameters before retrying). Values: `200, 401, 402, 404, 422, 429, 433, 455, 500, 501, 505`
`msg` optional	`string`	Response message, error description upon failure
`data` required	`object`
`data.taskId` required	`string`	The task ID can be used with the "Get Task Details" endpoint to query the task status.

HTTP 500

Server error.

Parameter	Type	Description & constraints
`code` required	`integer`	Response status code - 200: Success - Request has been processed successfully - 401: Unauthorized - Authentication credentials are missing or invalid - 402: Insufficient Credits - Account does not have enough credits to perform the operation - 404: Not Found - The requested resource or endpoint does not exist - 408: Timeout - No result has been returned for over 10 minutes. - 422: Validation Error - The request parameters failed validation checks - 429: Rate Limited - Request limit has been exceeded for this resource - 455: Service Unavailable - System is currently undergoing maintenance - 500: Server Error - An unexpected error occurred while processing the request - 501: Generation Failed - Content generation task failed - 505: Feature Disabled - The requested feature is currently disabled
`msg` required	`string`	Response message, error description when failed
`data` required	`object`

Task status and callbacks

For asynchronous tasks, keep the returned taskId. Query GET /api/v1/jobs/recordInfo?taskId=... or provide callBackUrl when creating the task. Only the account that created a task can access it or derive new resources from it.

A timeout can mean the submission was accepted. Inspect the existing request in your dashboard; do not create another task automatically. Callback delivery is retried and may arrive more than once. Deduplicate with X-VezAPI-Event-Id.

Files, logs and billing

Generated media normally follows a 14-day provider lifetime; uploaded files expire after 24 hours. Save the files you need before expiration. VezAPI streams registered files without keeping a permanent media library. Request logs are retained for two calendar months.

Credits are reserved before submission. Final deductions match actual discounted consumption one for one. Unknown usage pauses new paid requests. If available funds cannot cover final usage while protecting other reservations, settlement stays pending until funded; model usage cannot make the wallet negative. Time-based inputs require server-side metadata reads; a failed read prevents submission.