Word animations require a word_animation object (with style and words[]) on a text element. Only fields that differ from their defaults are shown.
duration is required on text elements. word_animation.words must be non-empty — the API returns 422 if the array is missing or empty.
time, duration, x, and y on the text element to control when and where the text appears. Word timestamps in words[] are absolute timeline seconds — if your text element starts at time: 5, the first word’s start should also be around 5, not 0.
Box highlight (CapCut style)
White text, colored box behind the active word only. No permanent background. This is the combination for CapCut / TikTok-style animated captions.
background_color is read by the box highlight renderer as the box color. Leave background unset (or false) so no permanent background box is drawn behind the full text.
{
"width": 1920,
"height": 1080,
"duration": 10,
"elements": [
{
"type": "video",
"id": "vid1",
"source_url": "https://cdn.example.com/clip.mp4",
"time": 0,
"in_point": 0,
"out_point": 10
},
{
"type": "text",
"id": "captions1",
"text": "What are we all thinking",
"font_family": "Arimo",
"font_size": 72,
"font_style": "bold",
"text_color": "#ffffff",
"background_color": "#8B2FC9",
"time": 0,
"duration": 6,
"x": "50%",
"y": "75%",
"width": "80%",
"z_index": 1,
"word_animation": {
"style": "box",
"words": [
{ "text": "What", "start": 0.0, "end": 0.3 },
{ "text": "are", "start": 0.3, "end": 0.5 },
{ "text": "we", "start": 0.5, "end": 0.7 },
{ "text": "all", "start": 0.7, "end": 0.9 },
{ "text": "thinking","start": 0.9, "end": 1.5 }
]
}
}
]
}
Glow highlight
Active word glows at full opacity; unspoken words appear dimmed.
{
"width": 1920,
"height": 1080,
"duration": 10,
"elements": [
{
"type": "video",
"id": "vid1",
"source_url": "https://cdn.example.com/clip.mp4",
"time": 0,
"in_point": 0,
"out_point": 10
},
{
"type": "text",
"id": "captions1",
"text": "Hello world today",
"font_size": 48,
"font_style": "bold",
"text_color": "#ffffff",
"time": 0,
"duration": 6,
"x": "50%",
"y": "85%",
"width": "80%",
"z_index": 1,
"word_animation": {
"style": "glow",
"words": [
{ "text": "Hello", "start": 0.0, "end": 0.8 },
{ "text": "world", "start": 0.8, "end": 1.6 },
{ "text": "today", "start": 1.6, "end": 2.4 }
]
}
}
]
}
Scale pop
Each word scales in hard on its timestamp. Good for high-energy music or hype content.
{
"width": 1920,
"height": 1080,
"duration": 10,
"elements": [
{
"type": "video",
"id": "vid1",
"source_url": "https://cdn.example.com/clip.mp4",
"time": 0,
"in_point": 0,
"out_point": 10
},
{
"type": "text",
"id": "captions1",
"text": "Big news today",
"font_size": 56,
"font_style": "bold",
"text_color": "#ffffff",
"time": 1,
"duration": 4,
"x": "50%",
"y": "45%",
"width": "70%",
"z_index": 1,
"word_animation": {
"style": "scale_pop",
"words": [
{ "text": "Big", "start": 0.0, "end": 0.5 },
{ "text": "news", "start": 0.5, "end": 1.0 },
{ "text": "today", "start": 1.0, "end": 1.8 }
]
}
}
]
}
All word animation styles
| Value | Description |
|---|
glow | Active word at full opacity; others dimmed |
box | Colored box behind active word — set background_color for the box color |
scale_pop | Active word scales in on its timestamp |
slide_up | Words slide up from below as they are spoken |
fly_in | Words fly in from above |
color | Active word changes color — set background_color for the highlight color |
