Tired of burning time adding subtitles to videos? There’s an API for that. The same Submagic you use in your browser can now integrate with your other apps and workflow. Try the Subtitle API.
Whether you’re building a SaaS tool, running an agency, or just sick of wasting hours inside editing software, subtitle APIs let you auto-generate captions at scale, and they’re a game changer for content teams who want to grow faster with less grunt work.
Let’s take a look at the best AI powered subtitle generator APIs on the market.
Subtitles aren’t just text. They’re visibility.
We’re not adding subtitles just for accessibility (although that's important). We’re doing it to increase watch time, boost engagement, and make videos impossible to scroll past.
On platforms like TikTok, Instagram Reels, and YouTube Shorts, 70–85% of users watch videos on mute. So if your video isn’t captioned, it’s basically invisible.
And if you're doing volume (I intend all my puns), repurposing long-form content, generating social clips for clients, publishing daily, you need an API or you'll go nuts.
So here’s the list of the best subtitle APIs that can help you scale smart.
Submagic – The best subtitle API
Submagic is the most accurate subtitle generator, and stylish, I’ve used. The no code version and API plugs right into your workflow.
You can use Submagic API to:
- Add subtitles in over 100 different languages, accurately.
- Add viral-style captions (with animations, emojis, colors, speaker names, etc.)
- Translate subtitles to other languages with AI video translator
- Drop in b-roll, auto zooms, music, and sound effects, in 3 clicks
And yes, it’s available via API or via no code integrations with apps like Zapier, Make.com n8n and such. Whether you’re building your own video tool or running an agency that batches client content, this API saves hours each week.
Try the best subtitle generator API. Get your API Key and you’re off to the races. See how you can automate subtitles.
Opus Clip: AI meets editing
Opus Clip is mostly known for turning long-form videos into shorts with AI, but it also generates subtitles as part of that process, and you can access that via their API.
Best for: People looking to turn podcast or YouTube episodes into short viral clips with subtitles included.
Limitations: As I write this, the API is yet limited to select few as it’s in closed beta. So it might not even be an option. However, given the caliber of Opus Pro, when they release the API to the public it surely could take the silver medal. That’s why it’s on the C tierlist.
Creatomate
Creatomate is a flexible video automation tool that’s great for generating dynamic, branded content via API—including subtitles. If you’re building a platform that spits out custom videos at scale (think: real estate listings, social media updates, or SaaS demos), Creatomate lets you generate captions as part of the full video generation flow.
Best for: Automating branded video creation with dynamic data + subtitles
Shotstack
Shotstack is a full-blown video editing API with everything from transitions to timeline editing—and yes, that includes subtitles. It’s powerful and built for developers who need to render entire videos server-side with precise control.
Best for: Developers building full custom video rendering pipelines that need subtitle support baked in. Should you want to read more about Creatomate vs Shotstack.
Bannerbear
Bannerbear is designed for creative automation, Image, video, and even subtitle overlays via API. It’s perfect for makers or devs who want to auto-generate social clips or branded templates that include captions without touching an editing tool.
Best for: SaaS founders and makers building custom video flows with subtitle support
AssemblyAI: Geared more toward developers
If you’re building a full-blown video app and want subtitle generation as a backend feature, AssemblyAI gives you a powerful speech-to-text API.
Strengths:
- Supports dozens of languages
- Word-level timestamps
- Real-time transcription
Heads up: You’ll need to build the caption styling yourself, this API gives you the text, not the design. If this level of style control is important to you then Submagic also offers custom subtitle templates that you can just call by ID.
Rev.AI: Transcription API with subtitle support
Rev.ai is the tech behind Rev’s transcription services. It gives you an accurate speech-to-text API that outputs subtitle files (like .srt or .vtt).
I need to confirm this but I assume the generated subtitles could also be sent via JSON.
Best for: Teams that need reliable transcription and already have a way to render styled captions in their video pipeline. It does a great job transcribing and is more of a speech to text platform.
Not for: People looking for flashy captions or a user-friendly experience. This one’s built for devs.
Deepgram: Fast and developer-friendly
Deepgram is another AI speech to text API that supports subtitle generation. It’s lightning fast, supports real-time transcription, and is priced for scale.
Pros:
- Good documentation
- Fast response times
- Flexible models for noisy environments
Cons: No built-in video styling or subtitle rendering. You’ll get the text, but have to do the rest.
As you can tell, this is the wild West era of video editing APIs. So many companies offering bits and pieces of what creators need.
If you’re asking “Is there no one who understands how video editors and content creators work?” then Submagic is the answer. It packs all the goodies you need to get from that hefty, raw video file to a pushing a polished video live.
Recap of the best subtitle APIs
| Tool |
Subtitle Styling |
API Access |
No-Code Option |
Best For |
| Submagic |
Yes (animated, styled) |
Yes |
Yes |
Creators, agencies, viral clips |
| Opus Clip |
Yes (basic) |
Closed Beta |
No |
Repurposing long-form to shorts |
| AssemblyAI |
No |
Yes |
No |
Developers, custom video apps |
| Rev.ai |
No |
Yes |
No |
Raw subtitles, enterprise use |
| Deepgram |
No |
Yes |
No |
Speed, transcription at scale |
Here’s the key takeaways.
If you want subtitles that look good and actually help your videos perform, go with Submagic’s API.
You’ll get everything:
- Styled subtitles that grab attention
- Fast turnaround
- Dead-simple integration (even if you hate APIs, you can still use our no-code option)
And hey, if you're building tools for creators or running an agency? You’ll save hours. That means more client wins, faster delivery, and fewer late nights stuck syncing text to audio.
Want to see what Submagic can do before messing with the API? Start with the subtitle generator. It’s just as magical as it sounds.
Let me know if you want help integrating it. Happy to guide you. Connect with me on LinkedIn or join our Discord channel.
