Runway Gen-4.5 vs Veo 3.1 vs Seedance: Video API Compared

If you have looked at Google Trends for the word "runway" lately, you have seen something funny. Next to the airport runways and the reality TV show, three searches are shooting up: Runway Gen-4.5, Veo 3.1 and Seedance. Several of them are flagged "Breakout" by Google, which means they are growing faster than almost anything else around them.

Those are all AI video generators, and they now come with APIs. That means a developer (or a founder with a developer) can type a sentence and get a short video back, inside their own app. Product demos, social ads, explainer clips, game trailers: all of it can be generated on demand.

So which one should you build on? We went through the official pricing pages and documentation for all three, did the maths for you, and wrote down what we could and could not confirm. If you are brand new to APIs, you may also like our guide to what a REST API is. Everything below makes sense without it.

A quick note on honesty#

We are going to be upfront about two things.

1. We did not run a side-by-side quality test. Whether a video "looks better" is personal and changes with every model update. We compare what can be checked: price, clip length, resolution, sound, storage and risk. For quality, we tell you how to test it yourself.
2. Video AI changes monthly. Prices and limits below were taken from the providers' own pages on 15 October 2026. Where a number came from a third-party site and not the provider, we say so.

The short answer#

• Pick Veo 3.1 if you want video with built-in sound (voices, effects, music) and sharp resolution up to 4K. Its Fast and Lite versions are cheap. The catch: it is still labelled Preview.
• Pick Runway Gen-4.5 if you want a mature, simple API, a flat per-second price, and access to several other models through the same account.
• Pick Seedance if cinematic detail and multi-reference control matter most, and you are happy to check pricing carefully, because it is billed differently by different sellers.
• Whatever you pick, add a backup. Video APIs are young, so models change and retire quickly.

Meet the three contenders#

Runway Gen-4.5#

Runway is a company that started as a tool for filmmakers and now sells its models through a developer API. Gen-4.5 is its flagship video model. It turns text, or a starting image, into a short clip.

What we could confirm:

• Price: Runway's pricing page lists gen4.5 at 12 credits per second, and a credit costs $0.01. That is $0.12 per second. Its cheaper gen4_turbo model is $0.05 per second.
• Clip length: Runway's help centre lists 5, 8 or 10 seconds for Gen-4.5 in the app. API references from third parties describe a similar range, but we could not read Runway's own API page in full, so check it before you build.
• Resolution and sound: Third-party sources report a 720p ceiling and no built-in audio. Treat that as "reported, please verify".
• One key, many models: This is Runway's sneaky strength. The same price list includes Google Veo, Seedance, Kling, Wan, Grok Imagine and more. One account can reach all of them.

Google Veo 3.1#

Veo is Google's video model, available through the Gemini API. Version 3.1 comes in three flavours: Standard (best quality), Fast (cheaper and quicker) and Lite (cheapest).

What Google's own pages say (pricing and Veo docs):

More things worth knowing:

• Sound is always on. Dialogue, effects and music come with the picture.
• Aspect ratios: 16:9 or 9:16 (landscape or phone-style vertical).
• 1080p and 4K need 8-second clips.
• Extending a video adds 7 seconds at a time, up to 20 times, for a total of 148 seconds. Extensions run at 720p only.
• Everything is watermarked with Google's invisible SynthID mark.
• Status: Preview. Google lists all three Veo 3.1 models as Preview, and marks Veo 3 as deprecated.

Seedance (from ByteDance)#

Seedance is ByteDance's video model family, the company behind TikTok. Searches for it have surged, and the model has gone through several versions fast: 2.0, a Fast and a Mini variant, and now 2.5, which BytePlus describes as its mainline video model.

This is the trickiest one to compare, because it is sold in more than one way:

• Directly from ByteDance's international arm, BytePlus, which prices video per million tokens (tokens are the unit AI models use to meter their work). BytePlus's product page lists Seedance 2.0 at roughly $4.30 to $7.70 per million tokens, depending on resolution and whether you send a video as input. Seedance 2.5 is listed at $6.40 to $10.70. Turning tokens into seconds of video takes a calculation that we could not confirm, so check BytePlus's own calculator.
• Through Runway, which prices it per second like everything else (see below).
• Through resellers, which charge their own rates. Be careful here, since some are not official.

On Runway's published price list:

Seedance 2 also has a 4K option at $1.50 per second on that list. Runway also lists limits such as a combined 30-second cap on input and reference video for Seedance 2.5.

We could not confirm Seedance's maximum clip length or its audio support from official pages in our research, so we are not going to guess. Check BytePlus's documentation for those.

What does one clip actually cost?#

Per-second prices are hard to feel. Here is the same thing as one 8-second clip at 720p:

Two things jump out.

1. The spread is eight times. The same 8 seconds can cost 40 cents or over 3 dollars. In a real product that is the difference between a feature that makes money and one that loses it.

2. Veo 3.1 prices already include sound. Gen-4.5 reportedly does not, so if you need audio you will pay for a second tool and a bit of engineering on top.

What a month looks like#

Say your app makes 1,000 clips a month, each 8 seconds at 720p:

And that is before retries. People click "regenerate" a lot, so add 20-30% to your estimate.

A tip we would follow ourselves: use the cheap model (Veo Lite, Veo Fast or Gen-4 Turbo) for previews, and only run the expensive model once the user is happy with the idea. This one habit can cut a video bill dramatically.

Things that will bite you in production#

Pretty demos hide the boring parts. These are the ones to plan for.

1. Video takes time#

Unlike a text answer, a video can take from seconds to minutes. Google says Veo requests return a "job" straight away, and you check back until it is done. Its documentation says generation takes about 11 seconds to 6 minutes at peak times. Runway's tasks work the same way.

That means you should never make a user stare at a frozen button. Show progress, let them leave the page, and tell them when it is ready.

2. Files disappear#

Google says generated Veo videos are kept for 2 days and then removed. Other providers have their own limits. So the rule is simple:

Download every video the moment it is ready and keep it in your own storage.

3. "Preview" means "can change"#

Veo 3.1 is a Preview model, and Google has already deprecated Veo 3. Models get retired. Keep the model name in one setting, so changing it is a one-line fix.

4. Rules about people#

Google's Veo has rules about showing people. In some regions, including the EU, UK, Switzerland and the Middle East and North Africa, only adults are allowed in generated videos. If your users are global, handle rejected requests with a clear, friendly message.

5. Clips are short#

Everything here makes clips of a few seconds. A 30-second ad is several clips joined together. Veo can extend a clip in 7-second steps, and for other models you will stitch clips yourself.

6. Watermarks and disclosure#

Veo marks its videos with SynthID. Many platforms now expect AI content to be labelled. Check the rules where you publish.

A simple pattern that works for any of them#

The code below shows the shape of a video integration. It is deliberately provider-neutral, so you can plug in Runway, Veo or Seedance at the marked places.

// 1. Ask the provider to start a video job. Returns a job ID straight away.
const job = await startVideoJob({ prompt, seconds: 8, resolution: '720p' });
 
// 2. Check back every few seconds until it finishes (or fails).
let result;
while (true) {
  await sleep(10_000); // 10 seconds, the interval Google's own docs use
  result = await getJob(job.id);
  if (result.status === 'done' || result.status === 'failed') break;
}
 
if (result.status === 'failed') {
  throw new Error('Video failed. Try a backup provider.');
}
 
// 3. Download the file NOW, because provider links expire.
const bytes = await download(result.videoUrl);
const ourUrl = await saveToOurStorage(bytes);
 
// 4. Give the user OUR link, not the provider's.
return ourUrl;

If you are new to this style of request, see our beginner guide to API request methods. Starting a job is a POST, and a POST is not safe to repeat. A double click can create two videos and charge you twice, so disable the button after the first click.

So which should you choose?#

Choose Veo 3.1 if...#

• You want sound created together with the picture.
• You need 4K or 9:16 vertical clips.
• You want a cheap option (Lite or Fast) for volume.
• You can live with Preview status and build a fallback.

Choose Runway Gen-4.5 if...#

• You want a simple, flat price and a mature developer experience.
• You like the idea of one account for many models, including Veo and Seedance.
• You are happy to add audio separately.

Choose Seedance if...#

• Cinematic detail and reference control are your top priority, and you have tested it on your own prompts.
• You have checked how you will be billed (BytePlus tokens or a per-second reseller) and what your region allows.

Best strategy for a real product#

Use one main model and one backup, and send both through a thin layer of your own code. Because Runway's API also sells Veo and Seedance, it can be the easiest way to try several models while writing only one integration.

How to test these yourself in one afternoon#

1. Write 10 prompts from your real product. Include a hard one: people talking, hands, text on screen, fast motion.
2. Make the same 8-second clip on two or three models at the resolution you will actually ship.
3. Show the results to a few people without saying which is which. Ask them to pick.
4. Write down the cost and the wait time for each clip.
5. Pick a main model and a backup.

It will cost you a few dollars and save you a lot of rework.

Checklist before you launch#

• The model name sits in a single setting
• You know whether your model is Preview or stable
• Jobs run in the background, with a progress screen
• Every video is downloaded to your own storage immediately
• The generate button is disabled after one click
• You use a cheap model for previews
• A second provider is ready as a fallback
• You set a monthly spending limit
• You checked rules for people, regions and AI labels
• You re-check prices every month

Summary#

• Runway Gen-4.5 is $0.12 per second. Veo 3.1 ranges from $0.05 to $0.40 per second depending on version, with sound included. Seedance sits in the $0.16 to $0.36 range at 720p through Runway, and is billed by tokens directly from BytePlus.
• An 8-second clip costs about 40 cents to about 3 dollars. The model you pick changes your margins.
• Veo videos disappear after 2 days, and Veo 3.1 is still Preview. Download everything, and keep a backup.
• We did not rank video quality. Test your own prompts on two or three models.
• One API key can reach several models through Runway's price list, which makes switching easy.

Next, read our guide to image generation APIs for production apps and browse all AI & ML APIs.