Grok Imagine 1.0 vs Veo 3.1 Lite — Video API Comparison 2026
You are building an AI video feature and you have narrowed it down to two options: Grok Imagine 1.0 and Veo 3.1 Lite. Both are available via the GenRelay API under the same authentication and endpoint pattern — but they differ significantly in pricing model, output modes, and the workloads they are suited for. This comparison covers every dimension that matters before you write integration code.
What are Grok Imagine 1.0 and Veo 3.1 Lite?
Grok Imagine 1.0 is xAI's text-to-video model, available via the GenRelay API. It bills per second of generated video at a flat rate of $0.010/second, making cost easy to predict for any known clip duration.
Veo 3.1 Lite is Google's production video generation model, also available via GenRelay. It bills per second of output but introduces a per-resolution multiplier: $0.060/second at 720p, $0.120/second at 1080p, and $0.180/second for the highest resolution tier. In addition to text-to-video, Veo 3.1 Lite supports image-to-video (i2v) and reference-video-to-video (ref2v) input modes.
Both use GenRelay's async video API — submit a job, poll for completion, retrieve the output URL. The integration pattern is identical; only the model parameter and optional resolution field differ. For per-model integration details, see the Veo 3.1 API tutorial and the Grok video API guide.
How do the two models compare across key dimensions?
| Dimension | Grok Imagine 1.0 | Veo 3.1 Lite |
|---|---|---|
| Text-to-video | Yes | Yes |
| Image-to-video | No | Yes |
| Reference-video-to-video | No | Yes |
| Resolution options | Fixed | 720p / 1080p / top tier |
| Billing unit | Per second | Per second × resolution tier |
| Rate at 720p | $0.010/s | $0.060/s |
| Rate at 1080p | N/A | $0.120/s |
| Max clip duration | Up to 8s | Up to 8s |
| Async job API | Yes | Yes |
| Output format | MP4 | MP4 |
| Cinematic camera control | Moderate | Strong |
How do pricing costs compare for real workloads?
Grok Imagine 1.0 is 6× cheaper per second than Veo 3.1 Lite at 720p. The gap widens at higher resolutions.
Cost per clip at common durations:
| Clip length | Grok 1.0 | Veo 3.1 Lite 720p | Veo 3.1 Lite 1080p |
|---|---|---|---|
| 5 seconds | $0.050 | $0.300 | $0.600 |
| 8 seconds | $0.080 | $0.480 | $0.960 |
Monthly cost at scale (1,000 clips × 8s each):
| Model + resolution | Monthly generation cost |
|---|---|
| Grok Imagine 1.0 | $80 |
| Veo 3.1 Lite, 720p | $480 |
| Veo 3.1 Lite, 1080p | $960 |
For a broader cost comparison that includes Omni Flash and Grok Imagine 1.5, see the cheapest AI video API breakdown.
How do I call each model via the GenRelay API?
Both models use the same endpoint and polling pattern. The only differences are the model value and the optional resolution parameter for Veo 3.1 Lite.
Grok Imagine 1.0:
import requests
import time
GENRELAY_KEY = "YOUR_GENRELAY_KEY"
BASE = "https://api.genrelay.ai/v1"
def generate_grok_video(prompt: str, duration: int = 8) -> str:
resp = requests.post(
f"{BASE}/videos/generations",
headers={"Authorization": f"Bearer {GENRELAY_KEY}"},
json={"model": "grok-imagine-1.0", "prompt": prompt, "duration": duration},
timeout=30,
)
resp.raise_for_status()
return _poll(resp.json()["id"])
def _poll(job_id: str, interval: int = 5, max_wait: int = 300) -> str:
deadline = time.time() + max_wait
while time.time() < deadline:
r = requests.get(
f"{BASE}/videos/generations/{job_id}",
headers={"Authorization": f"Bearer {GENRELAY_KEY}"},
)
data = r.json()
if data["status"] == "succeeded":
return data["output"]["url"]
if data["status"] == "failed":
raise RuntimeError(data.get("error", "generation failed"))
time.sleep(interval)
raise TimeoutError("job timed out")
Veo 3.1 Lite (with resolution selection):
def generate_veo_video(
prompt: str,
resolution: str = "720p",
duration: int = 8,
) -> str:
resp = requests.post(
f"{BASE}/videos/generations",
headers={"Authorization": f"Bearer {GENRELAY_KEY}"},
json={
"model": "veo-3.1-lite",
"prompt": prompt,
"duration": duration,
"resolution": resolution, # "720p" | "1080p"
},
timeout=30,
)
resp.raise_for_status()
# Veo jobs run longer; poll less aggressively to reduce request overhead
return _poll(resp.json()["id"], interval=8)
Notice that _poll() is shared — switching models in production requires only changing the generation call, not the polling or result-handling code. This is one of the advantages of a unified API surface.
Which model handles cinematic quality better?
Veo 3.1 Lite produces more photorealistic output with stronger adherence to camera motion descriptors such as "slow dolly in," "tracking shot," and "crane up." At 1080p the difference in sharpness and motion coherence is noticeable.
Grok Imagine 1.0 handles general scene descriptions reliably and performs well for short social-media-style clips where precise camera control is not a requirement. For clips under 8 seconds with simple prompts, the quality gap may not justify the 6× price difference for cost-sensitive use cases.
If output fidelity is the priority and cost is secondary, Veo 3.1 Lite at 720p ($0.060/s) often hits a good quality-per-dollar ratio: meaningfully stronger output than Grok Imagine 1.0 at a premium that may be acceptable for user-facing product features.
When should I choose one over the other?
Choose Grok Imagine 1.0 when:
- You are running a high-volume text-to-video pipeline (ad creative, social automation, content generation)
- Cost per clip is a primary constraint and simple prompts are sufficient
- Clips are short (4–8 seconds) and do not require 1080p fidelity
- You want predictable billing without resolution-based pricing variables
Choose Veo 3.1 Lite when:
- You need image-to-video or reference-video-to-video capability
- Output quality justifies higher cost for user-facing, premium features
- You are generating cinematic or product video content where visual fidelity matters
- You want to use 720p for previews and 1080p for final renders within the same workflow
For a full comparison including Gemini Omni Flash across more dimensions, see the best AI video generation API guide.
FAQ
Does Grok Imagine 1.0 support image-to-video?
No. Grok Imagine 1.0 is text-to-video only. If you need image-to-video, use Grok Imagine 1.5 ($0.022/s) or Veo 3.1 Lite, both available via GenRelay.
Does Veo 3.1 Lite generate audio alongside video?
Veo 3.1 Lite can generate video with audio when the prompt includes audio descriptors (ambient sound, dialogue cues). Refer to the current GenRelay documentation for audio parameter availability and defaults.
What is the maximum clip duration for each model?
Both models support up to 8 seconds per generation request as of September 2026. For longer videos, chain multiple generation calls and concatenate the output clips in post-processing.
How long do output video URLs remain accessible?
Output URLs are temporary. Download and store generated videos in your own storage (S3, GCS) immediately after the job completes to avoid expiry.
Can I switch between these models without rewriting my integration?
Yes. With GenRelay, changing the model parameter from "grok-imagine-1.0" to "veo-3.1-lite" is the only required change. Endpoint, authentication, polling logic, and response structure are identical. For Veo 3.1 Lite you can optionally pass resolution — if omitted, a default resolution is applied.
Pricing as of September 2026 via GenRelay. Verify current rates at genrelay.ai before building cost models.