LTX 2.5 API

Introduction

LTX 2.5 Text to video generates one continuous take of 5 to 20 whole seconds from a written brief, in 16:9 or 9:16, at 720p, 1080p, 2K or 4K. Only prompt is required; duration_seconds, aspect_ratio and resolution default to 5 seconds, 16:9 and 720p, and seed is optional. Every clip comes back with a generated soundtrack. Reach for this endpoint when nothing visual has been approved yet and the setting, action and camera all have to come from words. Requests run as asynchronous tasks: create the task, then poll it or take the callback.

Choose a LTX 2.5 mode by starting material

Key features

Up to twenty seconds in a single take

duration_seconds takes whole seconds from 5 to 20; the floor is 5, not 3. Twenty seconds is enough for an entrance, a hold and an exit inside one generated shot, so continuity across those beats is handled inside the generation instead of in your edit. The family has no extend task, which means length is set when you submit: a five-second draft and a twenty-second final are two separate generations, not one clip lengthened.

Four resolutions behind one field

720p, 1080p, 2k and 4k all come from the same request shape, and 2k returns a frame about 2560 px wide. Blocking and camera path can already be judged at 720p. What the higher tiers add is fabric weave, skin texture and specular detail, which is why the practical path is a 720p draft followed by a single high-resolution run with the seed unchanged.

Sound generated with the picture

The clip includes an audio track even though the endpoint has no audio field, so there is no switch to turn it off. Treat sound as part of the brief: the opera example ends with "orchestra tuning drifting up from the pit". When the clip goes under your own music and foley, mute or replace the track in the edit.

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 68 credits for a 5-second clip ($0.68).

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

Use cases

A long move with no cuts

The arena-gate-to-cages example runs at the 20-second maximum in 1080p and 16:9. Its brief describes one Steadicam path from an arena gate, through a packed terrace and a torch-lit tunnel, out to backstage cages, and says "No cuts" outright. Shots like this depend on the camera path and the set holding together at the same time, which is what a single long take is for.

Drafts that become 4K plates

Draft the take at 720p, keep the seed, then run the same prompt once at 4K; the resolution field is the only change. A 4K render carries enough detail to survive a grade, a reframe and a slow push added later in the edit. The copper-tub-candlelight example was rendered at 2k; its brief asks for steam, wet skin and flame light, the kind of fine texture the higher tiers are there for.

Prompt guide & pro tips

Write the shot in the order it happens

Keep the whole arc in one paragraph and state subject, action, camera and light as they occur. The opera-staircase brief is a working pattern: who she is and what she wears, then the descent and the slit opening with each step, then the light through the fabric, then "Slow crane down", then the sound. Place each camera instruction next to the action it follows.

Fix length and frame before the first word

Choose duration_seconds and aspect_ratio first, because they decide how much action the brief has to carry. The 20-second arena brief lists a sequence of places; the 5-second briefs each describe a single movement and its end. Only 16:9 and 9:16 exist, so a square or 4:3 deliverable is not available from this endpoint.

Change one variable per run

Hold seed constant while you reword a line or step up the resolution, so the comparison isolates that one change. A fixed seed makes two runs comparable; it does not promise the same clip frame for frame, so review the high-resolution pass again instead of assuming it matches the draft.

Know where written direction stops

A written shot leaves wardrobe, body and framing to the model, and re-runs drift, which shows more over twenty seconds than over five. When a face, a product or a composition has to stay as approved, move the shot to LTX 2.5 Image to video and supply that frame as image_url.

API quick start

Call the LTX 2.5 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 lightricks/ltx-2.5/text-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": "lightricks/ltx-2.5/text-to-video",
  "input": {
    "prompt": "A slow aerial shot drifting over a misty pine forest at sunrise",
    "resolution": "720p",
    "aspect_ratio": "16:9",
    "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.

LTX 2.5 API questions

All LTX models

MiniMax H3 covers more shapes and adds reference photos, but stops at 15 seconds. LTX 2.5 is the pick for 20-second takes and native 4K.

• LTX 2.5 APILong 20-second takes up to 4K with a soundtrackFrom 68 credits for a 5-second clip
• LTX-2.3 LoRA APILTX-2.3 clips with stereo sound and your own LoRAsFrom 18 credits for a 5-second clip
• LTX-2 19B API20-second clips with voices, music and effectsFrom 11 credits for a 5-second clip
• LTX-2 19B LoRA APILTX-2 clips with sound and your own LoRA stylesFrom 14 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
• Kling 3.0 API4K clips, multi-shot cuts and motion controlFrom 51 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
• Kling O3 APIKling’s unified model: create, animate, reference and edit up to 4KFrom 51 credits for a 5-second clip

More about LTX 2.5

Try it

LTX 2.5 AI Video Generator onlineCreate videos with LTX 2.5 in PopNow

Docs

LTX 2.5 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 LTX 2.5 results without polling