Burned-in captions
This draws the text directly onto the video frames. Viewers see it on any phone or app without having to turn a setting on. Most Reels, TikTok, and Shorts clips are made this way.
Short vertical video captions
Captions people can read with the sound off.
Most short videos get watched on mute.
Live demo
Runs in your browser.
Use KolWrite to transcribe your clip, fix any wording, and pick a caption style. Then export a vertical video for Reels, TikTok, and Shorts with the captions burned straight into the image.
- 9:16along with 1:1 and 4:5 frames
- Word by wordhighlights each word as it's spoken
- Burned inbaked directly into the video
- SRTfor platforms that accept caption files
Burned-in captions vs. caption files
You have two options for putting text on a video, and short-video platforms favor one over the other.
A separate caption file
Here, an SRT file goes alongside the video and the media player displays the text. YouTube lets you upload subtitle files for videos, though you should check each platform's help pages to see what they currently support.
Get both from one transcript
KolWrite generates both options from the same edited transcript. If you fix the spelling of a name once, it will be right in both the burned-in video and the SRT file.
How the caption styles work
On short videos, people read captions in quick bursts over a moving background.
Just a few words at once
You control how many words appear on a line so viewers can easily read each caption before the next one pops up.
Emphasis on the active word
Because every word is timed, our styles can highlight, enlarge, or fill in the exact word being spoken, much like karaoke.
Placed out of the way
Pick your font, size, colors, and screen position so the text doesn't get covered up by the app's own buttons and descriptions.
Turning a clip into a captioned vertical video
Transcribe your clip
Upload your video to KolWrite to get a transcript with exact timestamps for every single word.
Clean up the text
Fix any misspelled names, brands, or slang before you pick a style, since any typos will end up right on the screen.
Pick a style and frame
Select a caption style, set how many words show per line, choose a 9:16, 1:1, or 4:5 frame, and check how it looks in the preview.
Export and post
Download the video with the burned-in captions and upload it straight to your social app. You can also grab an SRT file if you need one.
For developers and AI agents
You can also run everything KolWrite does with a recording through our API. Send the address of an audio or video file from your own code or an AI coding agent, and you'll get back the transcript with word timings, speaker labels, and an SRT file if you request one.
Word timings and speakers
The JSON output gives you the start and end time for every segment, plus individual word timings on models that support alignment. Turn on speaker separation to include a speaker label on each segment.
SRT and translation
Pass output_format as srt if you want subtitles directly from the API. If you are using the Oracle models, you can also set translate_to to get the text back in another language.
Built for agents
The API console publishes plain-text instructions for an agent to read before writing code. This includes agent-instructions.md, along with llms.txt, which links to the full reference.
Example request. The key comes from an environment variable, and the console has the full reference.
curl -X POST https://app.kolwrite.com/transcribe \
-H "x-api-key: $KOLWRITE_API_KEY" \
-H "Content-Type: application/json" \
-d '{"audio_url": "https://example.com/video.mp4", "model": "oracle", "language": "auto", "output_format": "srt"}'
# Returns {"jobId": "..."}. Poll GET https://app.kolwrite.com/transcribe/{jobId}
# until status is COMPLETED. The result is the file or the JSON you asked for.Questions
How do I add captions to an Instagram Reel or a TikTok?
Upload your clip to KolWrite to transcribe it, fix any typos, pick a style, and export the video with the captions burned in. Then just post that file. Because the text is baked into the video, every viewer sees it automatically without turning anything on.
Can I upload an SRT file to Instagram or TikTok?
Usually, short-video apps either auto-generate their own captions or show text that is already part of the video file, rather than taking an uploaded SRT. If you want full control over the wording and design, burn the captions into the video. YouTube does take subtitle files, so you can export an SRT for that.
Can the captions highlight each word as it is spoken?
Yes. KolWrite tracks the timing of every individual word, allowing caption styles to highlight, enlarge, or color in the active word right as you say it.
Can I make a vertical 9:16 video with captions?
Yes. Just select the 9:16 frame when burning in your captions. We also include 1:1 and 4:5 options for standard feed posts.
Do captions work for Hebrew and Arabic videos?
Yes. KolWrite transcribes over 100 languages and formats Hebrew and Arabic captions properly from right to left.
Does the burned video carry a KolWrite mark?
If you are on a plan below Business, burned-in videos begin with a brief KolWrite credit. Upgrading to the Business plan removes it.
Caption your next clip.
Transcribe a short video, edit the text, and export it in a 9:16 frame with the captions burned in.