Is There a Free AI Video Generation API? Credits, Pricing & What to Expect
You want to add AI video generation to your app and start with the obvious question: is there a free API? The short answer is no — not at any meaningful scale. AI video generation is compute-intensive: a 5-second 720p clip requires significant GPU time, and providers pass that cost to developers. What does exist is free credits on platforms like GenRelay, which let you generate real production-quality video via API before committing to a paid plan.
This roundup covers every video model available on GenRelay as of August 2026, what the free credit period lets you test, and how to calculate costs once you scale.
What does "free AI video API" actually mean in practice?
When developers search for a free video generation API, they typically have one of three expectations:
- Free credits on signup: a fixed balance that lets you make real API calls at no cost. Spend it, then pay. This is how GenRelay works.
- Free tier with recurring limits: a monthly allowance — usually enough for development but not production volume. Some image APIs offer this; most video APIs don't because inference costs are too high.
- Open-source model, self-hosted: the model weights are publicly available, but you provision and pay for the GPU yourself. Not an API — requires infrastructure engineering.
Truly free, unlimited, production-grade AI video APIs do not exist in 2026. Veo 3.1, Gemini Omni Flash, and Grok Imagine all run on expensive inference hardware, and no provider has absorbed that cost for unrestricted API access.
What GenRelay offers: free credits on account creation, no credit card required to start. You call the real API, receive real video output, and measure generation quality and latency before billing activates.
What video models are available on GenRelay?
As of August 2026, GenRelay provides access to four video generation models across two billing structures:
| Model | Type | Billing | 720p | 1080p | 4K |
|---|---|---|---|---|---|
| Veo 3.1 Lite | Text-to-video | Per second | $0.060/s | $0.120/s | $0.180/s |
| Grok Imagine 1.0 | Text-to-video | Per second | $0.010/s | — | — |
| Grok Imagine 1.5 | Image-to-video | Per second | $0.022/s | — | — |
| Gemini Omni Flash | Text-to-video | Per generation | $0.10/gen | $0.15/gen | — |
The billing structure difference is significant for production planning. Per-second models (Veo 3.1 Lite, both Grok variants) charge proportionally to clip length — a 10-second clip costs exactly twice a 5-second clip. Omni Flash charges a fixed fee per generation regardless of duration, which simplifies cost prediction in user-facing products.
How far do free credits stretch across each model?
To give concrete numbers, here is what a $5 credit balance buys you per model at their lowest-cost configuration:
Grok Imagine 1.0 at 720p ($0.010/s)
- 5-second clip: $0.05 → ~100 clips from $5
- 10-second clip: $0.10 → ~50 clips
Gemini Omni Flash at 720p ($0.10/generation)
- Fixed per generation → 50 clips from $5
Grok Imagine 1.5 at 720p ($0.022/s)
- 5-second clip: $0.11 → ~45 clips from $5
Veo 3.1 Lite at 720p ($0.060/s)
- 5-second clip: $0.30 → ~16 clips
- 8-second clip: $0.48 → ~10 clips
Veo 3.1 Lite at 1080p ($0.120/s)
- 5-second clip: $0.60 → ~8 clips
If your goal is maximizing the number of test generations to evaluate prompt sensitivity, start with Grok Imagine 1.0. At $0.010/s, you can run 50–100 variations on a modest credit balance. If your goal is evaluating the highest-quality output available, use Veo 3.1 Lite — fewer generations but production-grade results.
How do I call the video API to use free credits?
Video generation is asynchronous on all models: you submit a job, receive an ID, then poll until completion. Here is a working Python example for Grok Imagine 1.0:
import requests
import time
# Submit job
resp = requests.post(
"https://genrelay.ai/v1/videos/generations",
headers={"Authorization": "Bearer YOUR_GENRELAY_KEY"},
json={
"model": "grok-imagine-1.0",
"prompt": "Aerial view of a dense forest at sunrise, slow forward camera movement, cinematic",
"duration": 5
}
)
job_id = resp.json()["id"]
print(f"Job submitted: {job_id}")
# Poll for result
while True:
status = requests.get(
f"https://genrelay.ai/v1/videos/generations/{job_id}",
headers={"Authorization": "Bearer YOUR_GENRELAY_KEY"}
).json()
if status["status"] == "succeeded":
print(f"Video URL: {status['data'][0]['url']}")
break
elif status["status"] == "failed":
print(f"Failed: {status.get('error')}")
break
time.sleep(10)
To test Veo 3.1 Lite — which supports audio generation and higher-fidelity motion — change the model and add a resolution parameter:
import requests
resp = requests.post(
"https://genrelay.ai/v1/videos/generations",
headers={"Authorization": "Bearer YOUR_GENRELAY_KEY"},
json={
"model": "veo-3.1-lite",
"prompt": "Ocean waves breaking on a volcanic beach at golden hour, natural ambient sound",
"duration": 5,
"resolution": "720p"
}
)
job_id = resp.json()["id"]
print(f"Veo 3.1 job: {job_id}")
# Poll /v1/videos/generations/{job_id} until status == "succeeded"
The endpoint is identical across models. Switching from Grok 1.0 to Veo 3.1 Lite requires only a change to the model field and optionally resolution.
Which model should I test first?
Test Grok Imagine 1.0 first if you want to maximize generation count. It is the most affordable per-second model and lets you run 50–100 clips on a limited credit balance to evaluate prompt behavior, generation speed, and integration patterns before spending on premium-tier inference.
Test Veo 3.1 Lite if your product requires high-quality motion and optional audio. Veo 3.1 Lite handles complex prompts more reliably, produces more coherent scene motion, and supports generated audio — capabilities Grok 1.0 does not offer. Budget 10–15 generations to evaluate it meaningfully.
Use Gemini Omni Flash when predictable per-generation cost matters more than per-second economics. If your app lets users generate clips and you want to charge a fixed credit per generation without calculating duration, Omni Flash's flat billing simplifies the accounting.
Use Grok Imagine 1.5 when your workflow is image-to-video: you have a source image and want to animate the subject. It runs at $0.022/s — more affordable than Veo 3.1 Lite while producing reference-consistent motion.
What does monthly cost look like once free credits run out?
Here is a cost estimate for an app generating 500 video clips per month:
| Model | Clip length | Resolution | Monthly cost (500 clips) |
|---|---|---|---|
| Grok Imagine 1.0 | 5s | 720p | $25 |
| Omni Flash | fixed | 720p | $50 |
| Grok Imagine 1.5 | 5s | 720p | $55 |
| Veo 3.1 Lite | 5s | 720p | $150 |
| Veo 3.1 Lite | 5s | 1080p | $300 |
For a more detailed breakdown by clip length and budget range, see Veo 3 API pricing — cost per second explained and Cheapest AI video generation API — price breakdown 2026.
FAQ
Can I use the free credits without a credit card?
Yes. GenRelay's free credits do not require a credit card to activate. Create an account, generate an API key, and start making API calls immediately. Billing only activates when you upgrade to a paid plan or top up credits.
Do free-credit videos have watermarks?
No. Videos generated on free credits go through the same API and produce the same clean output as paid usage. There are no watermarks, quality reductions, or resolution caps on free-tier generations.
Is Veo 3.1 available through a free Google API tier?
As of August 2026, Veo 3.1 is not available via Google's free tier for external developers. Access Veo 3.1 via GenRelay without requiring a direct Google enterprise agreement.
What is the minimum clip duration I can generate?
Duration minimums vary by model. Grok Imagine 1.0 supports clips from 3–10 seconds. Veo 3.1 Lite supports 5–8 seconds on the Lite configuration. Omni Flash generates a fixed-length clip per call regardless of the duration parameter.
What happens when free credits run out?
API calls return a 402 Payment Required error when your credit balance reaches zero. You can top up credits or activate a subscription. Already-generated video URLs remain accessible until their 24-hour expiry.
Does GenRelay offer a monthly recurring free tier after signup credits are spent?
No. The free credits are a one-time development budget. After they are consumed, ongoing usage requires credit top-ups or a paid plan. There is no recurring monthly allowance.