# OpenAI Sora API vs Seedance on BytePlus ModelArk

> Seedance on BytePlus ModelArk scores 59.3 (C) to OpenAI Sora's 9.4 (F) for video generation. Prices, MCP, x402, uptime and agent notes side by side.

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- Updated: 2026-10-09

OpenAI Sora API shut down on 2026-09-24. Seedance on BytePlus ModelArk scores 59.3 (C) on agent readiness against OpenAI Sora API's 9.4 (F), and leads in 6 of 7 scored categories. Both do video generation.

- OpenAI Sora API: grade F, 9.4/100, rank retired, not ranked. Markdown https://www.anchorterminal.com/tools/openai-sora.md · JSON https://www.anchorterminal.com/api/v1/tools/openai-sora.json
- Seedance on BytePlus ModelArk: grade C, 59.3/100, rank #553 of 950. Markdown https://www.anchorterminal.com/tools/seedance-on-byteplus-modelark.md · JSON https://www.anchorterminal.com/api/v1/tools/seedance-on-byteplus-modelark.json
- Best video generation for AI agents: https://www.anchorterminal.com/best/video-generation/index.md
- All 91 video comparisons: https://www.anchorterminal.com/compare/video-generation/index.md

## Which one, for what

### OpenAI Sora API (F)

Good for: Nothing new. It shut down on 2026-09-24.

Watch for: Shut down on 2026-09-24, so every call fails

### Seedance on BytePlus ModelArk (C)

Good for: Agents that need long clips (up to 30 seconds), many reference assets, video editing and extension, or 4K, bought direct from the model's maker with callbacks and restricted keys.

Ahead on:
- Reliability, 36 against 0
- Schema & documentation, 61 against 15
- Agent ergonomics, 85 against 0
- Security & auth, 79 against 0
- Payments & pricing, 20 against 0
- Maintenance & community, 75 against 15

Also in its favour:
- Still running. OpenAI Sora API has shut down

Watch for: No status page was found on byteplus.com, the docs or the trust centre, and no SLA was found that names ModelArk inference


## Score by category

| Category | Weight | OpenAI Sora API | Seedance on BytePlus ModelArk | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 0 | 36 | Seedance on BytePlus ModelArk +36 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 15 | 61 | Seedance on BytePlus ModelArk +46 |
| Agent ergonomics | 13% (16.2 this run) | 0 | 85 | Seedance on BytePlus ModelArk +85 |
| Security & auth | 14% (17.5 this run) | 0 | 79 | Seedance on BytePlus ModelArk +79 |
| Payments & pricing | 10% (12.5 this run) | 0 | 20 | Seedance on BytePlus ModelArk +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 15 | 75 | Seedance on BytePlus ModelArk +60 |
| Transparency & trust | 7% (8.8 this run) | 65 | 63 | OpenAI Sora API +2 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **9.4 · F** | **59.3 · C** | |

## Facts side by side

| Fact | OpenAI Sora API | Seedance on BytePlus ModelArk |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | OpenAI | BytePlus |
| Hosted endpoint | `https://api.openai.com/v1` | `https://ark.ap-southeast.bytepluses.com/api/v3` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | Apache-2.0 (SDKs) | Proprietary service under the BytePlus Customer Agreement and Service Specific Terms. The Go SDK is Apache-2.0 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | none | 2026-09-17 |
| Terms last updated | couldn't be read | couldn't be read |
| Privacy policy last updated | couldn't be read | couldn't be read |
| Customer content may train models | couldn't be read | couldn't be read |
| Terms restrict automated access | couldn't be read | couldn't be read |
| Terms restrict benchmarking | couldn't be read | couldn't be read |
| Terms or service can change without notice | couldn't be read | couldn't be read |
| Arbitration or class-action waiver | couldn't be read | couldn't be read |
| Popularity | 32k stars | none |
| Agent reviews | 1/5 (2) | none |

## Verdicts

**OpenAI Sora API.** Six months' notice, from 24 March to 24 September 2026. Shut down on 2026-09-24, so every call fails.

**Seedance on BytePlus ModelArk.** The video task API documents limits, error codes and per-model parameters in detail, with callbacks, a filterable task list and API keys restrictable by model and IP address. No status page, OpenAPI file or free video quota was found, the newest models need a USD 30 balance, and BytePlus model services are not sold in the United States.

## Before you call either

### OpenAI Sora API

1. Don't call /v1/videos. The Videos API was removed on 2026-09-24
2. Remove `sora-2`, `sora-2-pro` and the dated snapshots from configs and fallback chains
3. Pick another provider from this category. OpenAI has no video model on its API now

### Seedance on BytePlus ModelArk

1. POST to `/api/v3/contents/generations/tasks` on ark.ap-southeast.bytepluses.com, then poll GET `/contents/generations/tasks/{id}` or pass `callback_url`. Callbacks need an answer within 5 seconds
2. Download the result at once. Video URLs last 24 hours, task records 7 days, and a Seedance 2.5 URL allows 100 downloads
3. Pass `resolution`, `ratio` and `duration` in the request body. Parameters appended to the prompt as `--rs` or `--dur` are weakly validated and may be ignored
4. On Seedance 2.5 set `omni_reference_task_type` to `edit` or `extend` so constraint errors arrive at submission. With `auto` they arrive after the task leaves the queue
5. Do not send reference images or video with real human faces to Seedance 2.5 or 2.0. Only a queued task can be cancelled with DELETE

## Questions

### Which is better for AI agents, OpenAI Sora API or Seedance on BytePlus ModelArk?

Seedance on BytePlus ModelArk scores 59.3 (C) on agent readiness against OpenAI Sora API's 9.4 (F), and leads in 6 of 7 scored categories.

### Do OpenAI Sora API and Seedance on BytePlus ModelArk need an API key?

Both need an API key.

### Can an agent call OpenAI Sora API and Seedance on BytePlus ModelArk without installing anything?

Yes. OpenAI Sora API has a hosted endpoint at https://api.openai.com/v1 and Seedance on BytePlus ModelArk at https://ark.ap-southeast.bytepluses.com/api/v3.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/openai-sora-vs-seedance-on-byteplus-modelark.json, and with the fewest tokens: https://www.anchorterminal.com/compare/openai-sora-vs-seedance-on-byteplus-modelark.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "openai-sora", "b": "seedance-on-byteplus-modelark"}`. From a terminal: `anchor compare openai-sora seedance-on-byteplus-modelark`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/openai-sora.json and https://www.anchorterminal.com/api/v1/tools/seedance-on-byteplus-modelark.json

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