Minimax H3 Image Text To Image LoRA API Documentation

Minimax H3 Image Text To Image LoRA API Documentation

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MiniMax H3 Image, the open-weights release of MiniMax’s image model, generates detailed, photorealistic images from text prompts with custom LoRA weights, native output from 1K to 4K. Ready-to-use REST inference API, best performance, no coldstarts, affordable pricing.

Features

MiniMax H3 Image Open-Weights Text-to-Image LoRA runs the open-weights release of MiniMax H3 Image (weights published by MiniMax). It generates images from text prompts with up to 3 custom LoRA weights per request, natively at every resolution from 1k up to 4k.


Why Choose This?

  • Open-weights model — The open weights MiniMax released for H3 Image, the same model family as MiniMax H3 video.
  • LoRA support — Load up to 3 LoRA weights in one request, each with its own scale.
  • Native output up to 4K — Choose 1k, 1.5k, 2k, 3k, or 4k; every tier is generated at its own size.
  • Built-in prompt enhancement — Short prompts in any language are expanded into a detailed description before generation.
  • Flexible framing — Square, portrait, landscape, and ultrawide aspect ratios.
  • Multiple output formats — Export as JPEG, PNG, or WebP.

Parameters

ParameterRequiredDescription
promptYesText description of the image to generate.
aspect_ratioNoOutput aspect ratio: 1:1, 1:2, 2:1, 1:3, 3:1, 2:3, 3:2, 3:4, 4:3, 4:5, 5:4, 9:16, 16:9, 9:21, or 21:9. Default: 1:1.
resolutionNoOutput resolution: 1k, 1.5k, 2k, 3k, or 4k. Default: 1k.
output_formatNoOutput format: jpeg, png, or webp. Default: jpeg.
lorasNoUp to 3 LoRA weights. Each item uses {path, scale}, where path points to the LoRA file and scale controls its influence.
seedNoRandom seed. Use -1 for random generation.

Pricing

Pricing is based on the selected resolution, with a fixed $0.015 LoRA surcharge per generation included in the table.

ResolutionPrice per Image
1K$0.035
1.5K$0.045
2K$0.055
3K$0.095
4K$0.135

Aspect ratio, output format, and seed do not add separate charges.


Notes

  • prompt is required.
  • resolution defaults to 1k; output_format defaults to jpeg.
  • Use seed=-1 for random seed selection.
  • Up to 3 LoRA weights per request, each as {path, scale}.

Authentication

For authentication details, please refer to the Authentication Guide.

API Endpoints

Submit Task & Query Result

set -euo pipefail

export WAVESPEED_API_KEY="your-api-key"

REQUEST_BODY=$(cat <<'JSON'
{
  "prompt": "A cinematic ocean wave at sunrise, highly detailed",
  "aspect_ratio": "1:1",
  "resolution": "1k",
  "output_format": "jpeg"
}
JSON
)

# 1. Submit the prediction once. Never retry this request automatically:
# a retry after an unclear failure can create a second, billed task.
CHECK='The task may already exist. Check History or the predictions list before submitting again.'
if ! SUBMIT_RESPONSE=$(curl --silent --show-error --fail-with-body \
  --connect-timeout 10 --max-time 60 \
  -X POST "https://api.wavespeed.ai/api/v3/wavespeed-ai/minimax-h3-image/text-to-image-lora" \
  -H "Authorization: Bearer ${WAVESPEED_API_KEY}" \
  -H "Content-Type: application/json" \
  -d "${REQUEST_BODY}"); then
  printf 'Submit failed. %s\n' "${CHECK}" >&2
  exit 1
fi

TASK=$(printf '%s' "${SUBMIT_RESPONSE}" | jq 'if type == "object" and has("data") then .data else . end')
PREDICTION_ID=$(printf '%s' "${TASK}" | jq -r '.id // empty')
if [ -z "${PREDICTION_ID}" ]; then
  printf 'Submission response did not contain a prediction id. %s\n' "${CHECK}" >&2
  exit 1
fi
RESULT_URL="https://api.wavespeed.ai/api/v3/predictions/${PREDICTION_ID}/result"

# 2. Poll until the prediction reaches a final status.
BODY_FILE=$(mktemp)
trap 'rm -f "${BODY_FILE}"' EXIT
while true; do
  # Transient errors (429, 5xx) are retried, honoring Retry-After.
  HTTP_CODE=$(curl --silent --show-error --fail-with-body \
    --connect-timeout 10 --max-time 60 --retry 5 --retry-delay 2 \
    --output "${BODY_FILE}" --write-out '%{http_code}' \
    "${RESULT_URL}" \
    -H "Authorization: Bearer ${WAVESPEED_API_KEY}" || true)
  case "${HTTP_CODE}" in
    2??) ;;
    000|429|5??)  # dropped connection or temporary error: keep polling
      printf 'Task %s: HTTP %s, polling again in 10s\n' "${PREDICTION_ID}" "${HTTP_CODE}" >&2
      sleep 10; continue ;;
    *) printf 'Task %s: HTTP %s\n' "${PREDICTION_ID}" "${HTTP_CODE}" >&2
      cat "${BODY_FILE}" >&2; exit 1 ;;
  esac
  RESULT=$(jq 'if type == "object" and has("data") then .data else . end' "${BODY_FILE}")
  STATUS=$(printf '%s' "${RESULT}" | jq -r '.status // empty')

  case "${STATUS}" in
    completed) printf '%s\n' "${RESULT}" | jq '.outputs'; break ;;
    failed|cancelled|timeout|deleted)
      printf 'Task %s ended with status %s\n' "${PREDICTION_ID}" "${STATUS}" >&2
      printf '%s\n' "${RESULT}" | jq . >&2; exit 1 ;;
    *) sleep 2 ;;
  esac
done

Retry temporary errors only while polling, never the submit request. Errors, retries and timeouts

Parameters

Task Submission Parameters

Request Parameters

ParameterTypeRequiredDefaultRangeDescription
promptstringYes-The positive prompt for the generation.
aspect_ratiostringNo1:11:1, 1:2, 2:1, 1:3, 3:1, 2:3, 3:2, 3:4, 4:3, 4:5, 5:4, 9:16, 16:9, 9:21, 21:9The aspect ratio of the generated image. Defaults to 1:1.
resolutionstringNo1k1k, 1.5k, 2k, 3k, 4kTotal output resolution tier: 1k (~1 megapixels), 1.5k (~2.4 megapixels), 2k (~4 megapixels), 3k (~9.4 megapixels) or 4k (~16.8 megapixels).
output_formatstringNojpegjpeg, png, webpThe format of the output image.
lorasarray<object>No0 ~ 3 itemsList of LoRAs to apply (max 3).
loras[].pathstringYes--URL or the path to the LoRA weights.
loras[].scalenumberNo10 ~ 4The scale of the LoRA weights. This is used to scale the LoRA weight before merging it with the base model.
seedintegerNo--The random seed to use for the generation. -1 means a random seed will be used.

Every model also accepts the global request options enable_sync_mode and enable_base64_output; see their pages for details.

Response Parameters

ParameterTypeDescription
codeintegerHTTP status code (e.g., 200 for success)
messagestringStatus message (e.g., “success”)
data.idstringUnique identifier for the prediction, Task Id
data.modelstringModel ID used for the prediction
data.outputsarrayOutput values, usually URL strings; some models return text strings or structured result objects (empty when status is not completed)
data.urlsobjectObject containing related API endpoints
data.statusstringTask status. completed is successful; failed, cancelled, timeout, and deleted are failure terminal statuses.
data.created_atstringISO timestamp of when the request was created (e.g., “2023-04-01T12:34:56.789Z”)
data.errorstringError message (empty if no error occurred)
data.timingsobjectObject containing timing details
data.timings.inferenceintegerInference time in milliseconds

Result Request Parameters

ParameterTypeRequiredDefaultDescription
idstringYes-Task ID

Result Response Parameters

ParameterTypeDescription
codeintegerHTTP status code (e.g., 200 for success)
messagestringStatus message (e.g., “success”)
dataobjectThe prediction data object containing all details
data.idstringUnique identifier for the prediction
data.modelstringModel ID used for the prediction
data.outputsarray<string | object>Array of generated outputs (empty when status is not completed). Items are usually URL strings, but may be text strings or structured result objects, depending on the model.
data.urlsobjectObject containing related API endpoints
data.statusstringStatus: completed is successful; failed, cancelled, timeout, and deleted are failure terminal statuses
data.created_atstringISO timestamp of when the request was created
data.errorstringError message (empty if no error occurred)
data.timingsobjectObject containing timing details
data.timings.inferenceintegerInference time in milliseconds
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