Seedance vs Runway API for programmatic video: cost per second compared

RelayDance provides OpenAI-compatible access to ByteDance Seedance models with per-second pricing published at relaydance.com/models: Seedance 2.0 720p costs about $0.190 per second, Seedance 2.0 1080p about $0.470 per second, and Seedance Fast about $0.152 per second. Native 4K is billed at about $4.90 per 5-second clip. This article compares those Seedance rates for programmatic video and explains the billing model, since Runway API rates are not provided here.

Seedance per-second pricing

Seedance video generation on RelayDance is billed per second at four published tiers. According to relaydance.com/models, Seedance 2.0 at 720p costs about $0.190 per second, Seedance 2.0 at 1080p costs about $0.470 per second, and Seedance Fast costs about $0.152 per second. Native 4K uses a per-clip model at about $4.90 per 5-second clip. Choosing a tier depends on the resolution required: Seedance Fast is the lowest per-second rate listed, while 1080p carries the higher per-second figure. Clips can run up to 15 seconds per request, so a 5-second 720p clip at $0.190 per second totals about $0.95 before any other factors.

Cost per second table

The table summarizes the concrete Seedance rates provided by RelayDance for direct comparison.

Live per-model rates are maintained at relaydance.com/models. Runway API rates are not included in the provided facts, so they cannot be listed here. Billing is pay-as-you-go per generated video, which means cost scales with the seconds you generate rather than a fixed subscription tier.

Billing and failed requests

RelayDance bills only for successful generation, and errored calls carry no charge. According to the official relaydance.com docs, 「Failed or errored requests are never billed」. This matters for programmatic pipelines that retry on transient errors, because retries that fail do not add cost. Image billing follows a separate rule on gpt-image-2: image output is free and only input is billed, with image-to-image starting from about CNY 0.035, and 4K and 1K output cost the same. Payments are accepted via USDT and Stripe card. The pay-as-you-go structure means you can estimate cost directly from seconds generated multiplied by the per-second rate for the chosen tier.

OpenAI-compatible integration steps

Integration reuses the OpenAI SDK by changing the base URL, so no new client library is required. According to the official relaydance.com/docs, 「Set base_url to https://relaydance.com/v1 and keep your OpenAI SDK」. Follow these steps to submit a video task:

1. Create an API key at relaydance.com/console and send it as Authorization: Bearer YOUR_API_KEY.
2. Set base_url to https://relaydance.com/v1.
3. POST /v1/video/generations with model, prompt, seconds, and metadata (ratio, resolution, generate_audio, callback_url, content[]).
4. Poll GET /v1/video/generations/{task_id} until status is succeeded or failed, or set metadata.callback_url for webhook delivery.

Reference media go in metadata.content[] and are cited as @image1 to @imageN, supporting up to 9 reference images, 3 reference videos, and 3 audio tracks per request. See relaydance.com/docs for details.

FAQ

Are failed requests billed? No. According to the official relaydance.com docs, 「Failed or errored requests are never billed」, so errored and failed calls carry no charge.

What is the lowest published Seedance per-second rate? Seedance Fast is listed at about $0.152 per second at relaydance.com/models, compared with about $0.190 per second for Seedance 2.0 720p and about $0.470 per second for 1080p.

Do I need a special SDK to integrate? No. The API is OpenAI-compatible; set base_url to https://relaydance.com/v1 and keep your OpenAI SDK, authenticating with a Bearer API key created at relaydance.com/console.