Kling 2.1 API

About Kling 2.1

Kling 2.1 turns an opening frame into a 5 or 10 second clip at 720p or 1080p - the least expensive image-to-video tier in the Kling lineup, with no sound.

Call it with the model name kling/2.1/image-to-video on POST /jobs/createTask, from 27 credits for a 5-second clip ($0.27). New accounts get 30 free credits to try it in the Playground first.

Introduction

Kling 2.1 Image to video is the only mode this generation offers: send an opening frame and a prompt describing what happens next, choose a resolution of 720p (standard) or 1080p (pro), and get back a silent 5 or 10 second clip. A closing frame (last_image_url) is only accepted at 1080p.

Choose a resolution by budget

Key features

A closing frame, but only at 1080p

Set resolution to 1080p and add a closing frame alongside your opening frame, and the clip is built to land on that exact pose by the last frame.

No audio track on either tier

This model does not generate sound at all, on 720p or 1080p. That's a plain fact to plan around, not a defect - it suits footage that's headed into an edit that will add its own voiceover, music or sound design later.

First and last frames can stitch together cleanly

In one of our tests, a pier walk that opened in fog and closed on a near, forward-facing pose landed almost exactly on the supplied closing frame, with the wind and color grading carried consistently across the whole five seconds.

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.

Each task is rounded up to whole credits, so one run at the lowest tier costs 27 credits for a 5-second clip ($0.27).

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

Use cases

A two-frame sequence with a locked ending

Use the 1080p pro tier with both image_url and last_image_url when the exact final pose matters - the last shot before a cut, for instance.

Prompt guide & pro tips

Describe one continuous action, start to finish

The rooftop sword example above names a single arc from swing to a final guard stance; that single-beat structure is more reliable on this generation than several distinct actions packed into one prompt.

Don't expect long trailing details to hold their shape

Long hair, dragging fabric or trailing props are the kind of detail this generation can lose track of over 10 seconds - a long velvet train shortened visibly partway through one of our staircase tests. Keep those details short, or plan for a touch-up pass afterward.

Match your resolution choice to what the shot needs

Run a 720p test first when you're still settling the action or the camera move, and save the 1080p pro tier - with its optional closing frame - for the take you intend to keep.

API quick start

Call the Kling 2.1 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/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/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",
    "resolution": "720p",
    "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 API questions

All Kling models

Kling 2.1 Master is this generation's high-quality tier; Kling 2.5 Turbo adds 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

Try it

Kling 2.1 Image to Video AI onlineCreate videos with Kling 2.1 in PopNow

Docs

Kling 2.1 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 results without polling