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Usable 24 hours after sign-up, up to 5 runs per day and at most 2 credits per run. Other sign-in methods start without credits.
02
Examples
Real outputs from the public examples of this model on Replicate, with the prompt and settings that produced them. They were not generated live on this page.
Prompt
A dense, verdant jungle world made up of small lego-like pieces. We see a rainbow chameleon running through the 3D world, the camera in and out of focus.
Length: 0:08
Settings
aspect_ratio
16:9
duration
10
Prompt
A scene in new york city where all the cars and cabs start floating up. We see a girl watching the scene from the back. indie aesthetic, daytime
Length: 0:08
Settings
aspect_ratio
16:9
duration
10
Prompt
A scene in new york city where all the cars and cabs start floating up. We see a girl watching the scene from the back
Length: 0:08
Settings
aspect_ratio
16:9
duration
10
Example prompts
Examples from the Railwail catalog. They were not generated live on this page.
Cinematic
Length: 0:10
Woman walking through sunflower field, golden hour
03
About Runway Gen 4.5
TL;DRAs of September 23, 2026
Runway Gen 4.5 is a model by Runway in the Video generation category. On Railwail, Runway Gen 4.5 costs $0.144 per second of video. A default run of 5 seconds costs $0.72. Supported aspect ratios: 16:9, 9:16, and 1:1. Possible lengths: 5 or 10 s.
Background
About Runway
Founded 2018 · New York City, USA
Runway was founded in 2018 in New York City by Cristobal Valenzuela, Anastasis Germanidis and Alejandro Matamala-Ortiz, three NYU ITP graduates who set out to build AI-native creative tools. Runway co-authored the Stable Diffusion paper (Rombach et al., 2022) with CompVis and LMU Munich and has shipped Gen-1 (2023), Gen-2 (2023), Gen-3 Alpha (June 2024), Gen-3 Alpha Turbo (July 2024), Gen-4 (March 2025) and Gen 4.5 (mid-2025). Gen 4.5 is the incremental update to Gen-4 with higher fidelity, longer durations and improved character consistency. The company has raised over $300M from Google, NVIDIA, Salesforce Ventures and General Catalyst at a $3B+ valuation, and runs the annual AI Film Festival as well as Hollywood-studio partnerships.
Latent video diffusion model (Diffusion Transformer) with reference and motion adapters
Runway Gen 4.5 is a closed Diffusion Transformer operating on a learned spatio-temporal latent space, building on the Gen-4 foundation released in early 2025. The model is conditioned on a multilingual text encoder plus optional image, reference-frame and motion-reference inputs. Gen-4 introduced character-, object- and environment-reference modes that let users lock identity, props or backgrounds across multiple shots; Gen 4.5 expands the reference vocabulary and improves consistency for longer sequences. Native generation is up to 10 seconds per clip at 720p (with 1080p upscale), and Runway's editor chains generations into multi-shot scenes. Gen 4.5 also tightens the integration with Runway's Act-One performance capture, Motion Brush, Lip Sync and Camera Control features. Training uses internal video, licensed footage and partner data on Runway's multimodal training infrastructure.
Parameters
Undisclosed
Capabilities
Text-to-video and image-to-video at up to 720p (1080p via upscale)
10-second clips per generation, chainable into multi-shot scenes
Character-, object- and environment-reference modes for cross-shot consistency
Tight integration with Act-One performance capture, Motion Brush and Lip Sync
Strong cinematic camera-language and Camera Control sliders
Available via Runway web app, mobile app and API
Used in production by Hollywood studios for previs and inserts
Public model card and ongoing safety programme
Best for: film previs, ad creative, multi-shot narratives, character-driven content.
Training & license
Curated mix of internal video, licensed footage and partner data on Runway's multimodal training infrastructure; exact corpus size undisclosed.
License: Proprietary commercial licence via Runway Terms of Service; generated content usable commercially on paid plans.
Safety testing: Multi-stage moderation (NSFW, CSAM, celebrity-likeness, trademark); public model card; ongoing red-team programme and policy team.
curl https://railwail.com/api/v1/videos/generations \
-H "Authorization: Bearer $RAILWAIL_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "runway-gen45",
"prompt": "A slow drone shot over a misty pine forest at sunrise"
}'
# Response: {"job_id": "...", "status": "queued", ...}
# Poll until status is completed, failed or cancelled:
curl https://railwail.com/api/v1/jobs/JOB_ID \
-H "Authorization: Bearer $RAILWAIL_API_KEY"
import os
import time
import requests
API = "https://railwail.com/api/v1"
headers = {"Authorization": f"Bearer {os.environ['RAILWAIL_API_KEY']}"}
job = requests.post(
f"{API}/videos/generations",
headers=headers,
json={
"model": "runway-gen45",
"prompt": "A slow drone shot over a misty pine forest at sunrise",
},
).json()
while True:
status = requests.get(f"{API}/jobs/{job['job_id']}", headers=headers).json()
if status["status"] in ("completed", "failed", "cancelled"):
break
time.sleep(5)
print(status["status"], status.get("output_url"))
const API = "https://railwail.com/api/v1";
const headers = {
Authorization: `Bearer ${process.env.RAILWAIL_API_KEY}`,
"Content-Type": "application/json",
};
const job = await fetch(`${API}/videos/generations`, {
method: "POST",
headers,
body: JSON.stringify({
model: "runway-gen45",
prompt: "A slow drone shot over a misty pine forest at sunrise"
}),
}).then((r) => r.json());
let status;
do {
await new Promise((r) => setTimeout(r, 5000));
status = await fetch(`${API}/jobs/${job.job_id}`, { headers }).then((r) => r.json());
} while (!["completed", "failed", "cancelled"].includes(status.status));
console.log(status.status, status.output_url);
Runway Gen 4.5 is a model by Runway in the Video generation category. On Railwail you can call it with an API key through the Railwail API.
How much does Runway Gen 4.5 cost on Railwail?
On Railwail, Runway Gen 4.5 costs $0.144 per second of video. A default run of 5 seconds costs $0.72. The price is known before the run starts. Usage is paid from prepaid credits; 1 credit equals $0.01.
Which settings does Runway Gen 4.5 support?
According to its input schema, Runway Gen 4.5 knows these parameters: prompt, duration (5 or 10), start_image, and aspect_ratio (16:9, 9:16, or 1:1).
How fast is Runway Gen 4.5?
There are not enough measured runs of Runway Gen 4.5 on Railwail yet to state a run time. It depends on the input, the settings and the load at the provider.
Is Runway Gen 4.5 better than Google Veo 3.1?
That depends on the task. Runway Gen 4.5 (Runway) and Google Veo 3.1 (Google DeepMind) are both models in the Video generation category. The comparison page shows their prices and specifications side by side.
Create a Railwail API key and send your request with the model ID runway-gen45. Code examples for curl, Python and JavaScript are in the API section of this page.
