fal-ad-variations

fal ad variations, in three formats

Render a set of social ads from one product brief. The script reads variations.csv, generates three stills per row with the FLUX.1 [dev] model on fal, then renders each row from one template in 9:16, 1:1 and 16:9. You get nine MP4 files in output/ and a manifest that records every render.

The script is resumable. It skips a render that is already in the manifest, and it reuses images it generated earlier, so a second run costs nothing at fal.

Requirements

• A Shotstack account and your production API key
• A fal account and an API key
• Node.js 20 or later

Each row generates three images at fal. Nine renders consume Shotstack credits. Set SHOTSTACK_ENV=stage in .env and use your sandbox key for free watermarked test renders.

Setup

git clone https://github.com/shotstack/shotstack-cookbook.git
cd shotstack-cookbook/examples/fal-ad-variations
cp .env.example .env

Load the file into your shell. Do this in each new terminal:

set -a
source .env
set +a

Edit variations.csv. Each row is one ad: an id, an image prompt, a headline, a cta and an accent colour.

Run

node ad-variations.mjs

What happens

The script reads each row of variations.csv and sends the prompt to fal. It puts the three image URLs and the row's text into the merge fields of template.json, then submits one render per output format. It polls every five seconds until each render reaches done or failed, downloads the MP4 to output/, and writes output/manifest.json after every step.

Run the script again to render only what is missing. Delete a row from manifest.json to force that render again. To change the look, edit template.json: the {{HEADLINE}}, {{CTA}}, {{ACCENT}} and {{IMG1}} tokens are replaced at render time by the merge field.