Ad variants at scale
One master, every size, every market, every brand. Change the headline, the offer or the language and get 48 finished ads back before the meeting ends.
See the recipe →Video editing,
automated.
One request in, a finished on-brand video out. Set the template once and every post, product or row renders on its own.
{ "type": "compose", "params": { "output": { "format": "mp4" }, "timeline": { "scenes": [ { "clips": [ /* lighthouse */ ] }, { "clips": [ /* the keeper */ ] }, { "clips": [ /* the ship */ ] } ] } }}Works with the tools you already use
What you can make
Video your team would otherwise make by hand
Every card here is a Compose render: footage in, a designed template on top, a finished video out. Swap the words, the brand or the size and the next one renders the same way.
Illustrated stories
Drawings, a voiceover and captions become a finished episode. Each scene sketches itself in, for every story you publish.
See the recipe →Real estate listings
Every new listing becomes a video tour: the photos, the price, the address and the open house, rendered straight from the listing feed.
See the recipe →Product sales and drops
One promo per product, with its photo, old price, new price and discount, re-rendered the moment a price changes.
See the recipe →Ways to compose
Three ways to compose your videos
From your product
Your app sends the content, Compose sends back the video. A few lines in any language. Your users never know there was a render.
From a workflow
A step in n8n, Make, Zapier or Activepieces. A new spreadsheet row, a new order, a new post, and a video follows.
From an AI agent
Describe the video to Claude or ChatGPT and it makes it, checks it, and hands you the file.
Compared
Compose next to the alternatives
The same job everywhere, a JSON description in and a finished video out. Compose costs the least of the four, and a short video comes back in 17 to 24 seconds.
One 10-minute video, at each entry price
- Compose 5x less
~$0.40
no subscription
- Shotstack
$2.00
pay as you go
- JSON2Video
~$4.16
pre-paid pack, no subscription
- Creatomate
~$8.40
Essential plan, $54 a month
One 10-minute 1080p video at each entry price. Compose is also below every published tier of all three, volume plans included.
| What you get | Compose Rendobar | Shotstack Full comparison | JSON2Video Full comparison | Creatomate Full comparison |
|---|---|---|---|---|
| Free to start | Yes. $5 credit, no card | With a catch. 10 credits, valid 30 days | With a catch. About 10 minutes, watermarked | With a catch. 50 credits |
| No subscription needed | Yes. Billed per second of video | Yes. Pay as you go | Yes. Pre-paid packs | No. Plans from $54 a month |
| 4K output | Yes. 4K at 60 fps on Studio, $29/mo, same rate | With a catch. From the $99 Pro plan | Yes. Same credit rate as 1080p | With a catch. Costs more credits per second |
| Raw FFmpeg on the same key | Yes. Yes | No. Templates and presets only | No. No | No. No |
| Hosted MCP server for AI agents | Yes. Hosted, no install | Yes. Hosted server | With a catch. Local server, installed with npx | Yes. Hosted server |
| Visual template editor | No. No, API first | Yes. White-label editor, every plan | Yes. Template library and editor | Yes. Visual template editor |
Yes With a catch No
Checked against each public pricing page: Shotstack 2026-10-20, JSON2Video 2026-10-20, Creatomate 2026-10-20.
The full breakdowns: Shotstack alternative, JSON2Video alternative, Creatomate alternative, JSON video API pricing compared.
FAQ
Questions about the Compose API
What is the cheapest JSON to video API?
Rendobar's Compose API, at $0.04/min of finished video, billed per second with no subscription. A 10-minute 1080p video costs $0.40. At each entry price the same video costs $2.00 on Shotstack (pay as you go), about $4.16 on JSON2Video (pre-paid pack, no subscription) and about $8.40 on Creatomate (Essential plan, $54 a month). The one lower rate on a published price list is Zvid's Business plan paid a year upfront, $0.0297 a minute if every credit gets used.
Which video editing API is fastest?
Compose returns a video of 6 to 20 seconds in 17 to 24 seconds, measured from the request to the finished file. A 21-minute timeline renders in 373 seconds, where the previous engine took 837, so a long video takes less than half the time it used to. Progress and an ETA stream while the job runs, so your app can show them.
Which JSON video API has the most editing features?
Compose lists 117 features in 12 groups, each with its JSON field and a rendered preview. That covers 34 picture and sound effects, keyframes on every property with 33 easings, 7 transition kinds plus custom wipes, kinetic text, 3D turns, Lottie, Google Fonts by name, nested compositions, scenes, subtitles, timers, shapes, blend modes, chroma key and LUTs. Every feature costs the same rate.
How much does a JSON video render cost?
On Compose, $0.04/min of finished video, billed per second, with a 15-second minimum of $0.01. The rate is the same on every plan and for animated graphics. POST /compose/validate checks a timeline for free and returns its price before you render. Signup includes $5 of credit, 125 minutes of video. Pro ($9/mo) renders up to 1440p at 30 fps and Studio ($29/mo) up to 4K at 60 fps.
What is a good Shotstack alternative?
Compose. Both render video from a JSON timeline, and Compose costs $0.04/min with no subscription, a fifth of Shotstack's pay-as-you-go rate and below the $0.05 a minute of its $499 Volume plan. Studio renders 4K at 60 fps for $29/mo, and raw FFmpeg runs on the same key. Choose Shotstack if non-developers need a white-label visual editor.
What is a video composition API?
A video composition API renders a finished video from a description instead of an editing program. Compose, Rendobar's video composition API, takes a JSON timeline of tracks, clips, text, transitions and audio, and returns the rendered file as MP4, WebM, GIF, MP3, JPG or PNG.
How do I turn JSON into a video?
Send the JSON timeline to POST https://api.rendobar.com/jobs with the type "compose". Rendobar validates it, renders it and returns a URL to the finished file, or delivers it to your own storage, with a webhook when it is ready. The TypeScript SDK, the MCP server and the n8n, Make and Zapier integrations send the same request.
What resolutions and formats can Compose render?
Free renders up to 1080p at 30 fps, Pro up to 1440p at 30 fps and Studio up to 4K at 60 fps, at the same per-second rate. Any frame shape works, vertical, square or wide. Output is MP4, WebM or GIF for video, MP3 for sound, and JPG or PNG for a single frame. Animated graphics, such as kinetic titles and 3D turns, render up to 1080p at 30 fps on every plan.
Can I use my own fonts, footage and logos?
Yes. Any Google Fonts family renders by name, and your own font file loads from a URL. Footage, images, audio and logos come from any public URL, a file you upload, or your own storage bucket.
Can AI agents like Claude or ChatGPT render videos?
Yes. Rendobar's hosted MCP server connects Claude, ChatGPT and Cursor in one step. The agent writes the timeline, checks it with validate_compose so a mistake costs nothing, renders it and hands back the file. Keys can be scoped so an agent only creates and reads jobs.
Scale your video generation.
Create an account and render your first videos on $5 of free credit. No card, no subscription.
Recent changes
All updates- Fixed
Compose refuses clip URLs it cannot reach at submit
A compose clip on localhost or a private network is refused at submit with the clip's path, instead of a render that fails without a reason.
- Improved
Engine filters list moves to the filters field
GET /compose/effects/engine lists every filter an engine effect can name in a new filters field. The old services field stays in the response, always empty.
- Improved
Render compose videos faster, priced by length
Long compose videos finish in less than half the time on a new engine, and you pay for the seconds of video you get back, at $0.04 a minute.