Kling 2.1 Master API

Introduction

Kling 2.1 Master Image to video animates an opening frame into a 5 or 10 second clip at 1080p, with no audio track and no closing frame option on this endpoint - only image_url.

Choose a Kling 2.1 Master mode by starting material

Key features

The frame holds, the prompt supplies the motion

The opening frame's wardrobe, pose, lighting and setting all stay exactly as sent; the prompt only needs to describe what happens next and where the camera goes. In our tests, a frozen ocean wave and an underwater ballroom gown both came alive convincingly straight from a single still, with the framing and costume left untouched.

No closing frame on this endpoint

Unlike Kling 2.1's standard image-to-video, Master's image-to-video takes only image_url and no last_image_url. If a specific ending pose matters, describe it directly in the prompt and let the model work toward it, rather than expecting a second frame to lock the finish in.

Vertical frames can leave the face reading smaller

When the opening frame is a vertical crop, the render follows suit, and in one of our tests the face came through smaller and slightly less detailed than it would from a landscape frame. A tighter facial crop in a vertical opening frame carries more detail into the finished clip.

Request parameters

Pricing

Prices are in credits, the same credits you use on the website (1 credit = $0.01). The hold is taken when the task is accepted and settled to the actual charge when it finishes; failed tasks are refunded.

For an exact number before you run, send the same body to POST /jobs/quote.

Use cases

Atmospheric motion: fabric, water, fire, dust

Flowing gowns, curling waves, drifting mist and a swaying chandelier all rendered naturally in our tests from a still frame plus a prompt describing the motion, which suits any shot built around atmosphere rather than dialogue or fast action.

Prompt guide & pro tips

Tell the still frame's elements when to move

Point at what's already in the frame - a wave, a pose, an outfit - and describe the order in which it should come alive, rather than re-describing the whole scene from scratch; the model already knows what the image looks like.

Crop the face a little tighter on vertical frames

If the opening frame is a vertical crop, frame the face closer than you would for a landscape shot; a wide vertical crop can leave the face reading small once the clip is in motion, as it did in one of our vertical-frame tests.

API quick start

Call the Kling 2.1 Master API in three steps

1. Create an API key. Sign in to PopNow and create a key in the API console. Keys start with sk-popnow- and use the same credits as the website.
2. Send the request. POST /jobs/createTask with model kling/2.1-master/image-to-video and an input object that follows the parameter table. The response returns a task ID straight away.
3. Get the result. Poll GET /jobs/recordInfo with the task ID, or pass a callBackUrl and we post the result to it. Download the output links when the task succeeds.

# 1. Create the task. Keep the Idempotency-Key if you retry after a network error.
export IDEMPOTENCY_KEY="$(uuidgen)"
curl -X POST https://api.popnow.ai/api/v1/jobs/createTask \
  -H "Authorization: Bearer $POPNOW_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $IDEMPOTENCY_KEY" \
  -d '{
  "model": "kling/2.1-master/image-to-video",
  "input": {
    "prompt": "A slow aerial shot drifting over a misty pine forest at sunrise",
    "image_url": "https://media.popnow.ai/influencer/examples/marco.webp",
    "duration_seconds": 5
  }
}'

# 2. Copy data.taskId from the response, then poll until state is succeeded, failed, canceled or expired.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $POPNOW_API_KEY"

Replace the prompt and any links with your own. The API tab has the response, polling and callback reference.

Kling 2.1 Master API questions

All Kling models

Kling 2.1 is the same generation for less per second; Kling 3.0 is the flagship with 4K and sound.

• Kling 3.0 API4K clips, multi-shot cuts and motion controlFrom 51 credits for a 5-second clip
• Kling O3 APIKling’s unified model: create, animate, reference and edit up to 4KFrom 51 credits for a 5-second clip
• Kling 3.0 Turbo APIFaster Kling 3.0 with sound on every clipFrom 84 credits for a 5-second clip
• Kling Avatar 2.0 APIA portrait that speaks or sings your audio, up to 5 minutesFrom 7.68 credits per second
• Kling 2.6 API1080p clips with optional sound and motion controlFrom 52 credits for a 5-second clip
• Kling 2.5 Turbo API1080p clips with a soundtrack on every takeFrom 42 credits for a 5-second clip
• Kling 2.1 Master APISilent 1080p clips with fine prompt controlFrom 162 credits for a 5-second clip
• Kling 2.1 APIAnimate a frame at 720p or 1080p, with an optional end frameFrom 27 credits for a 5-second clip

Other video APIs

• MiniMax H3 APIExpressive clips with audio, up to 2KFrom 28 credits for a 5-second clip
• Seedance 2.5 APIByteDance's newest: 30-second clips with native audioFrom 56 credits for a 5-second clip
• Vidu Q4 Preview APIUp to 4K clips with sound and spoken dialogueFrom 34 credits for a 5-second clip
• Wan 3.0 APIUp to 30-second clips with synced audioFrom 34 credits for a 5-second clip
• MiniMax H3 Max APIFast clips with ambience, effects and musicFrom 38 credits for a 5-second clip
• LTX 2.5 APILong 20-second takes up to 4K with a soundtrackFrom 68 credits for a 5-second clip

More about Kling 2.1 Master

Try it

Kling 2.1 Master AI Video Generator onlineCreate videos with Kling 2.1 Master in PopNow

Docs

Kling 2.1 Master model ID and input schema in the API docsPopNow API quickstart: your first request in five minutesImage to video guide for the PopNow APIWebhooks: get Kling 2.1 Master results without polling