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The video key — BytePlus ModelArk

This one key drives the two things the studio spends money on: video takes on Seedance and stills in the Art Dept on Seedream. Without it nothing renders.

Whereconsole.byteplus.com/ark
Costspay per token, ~$0.35 for a 5s take at 480p
Setup timeabout 15 minutes, most of it verification
Read this before you start. Creating the key is the easy half. The half that stops people is that models must be activated separately, and activation only unlocks once your account holds money. Skip it and every render comes back ModelNotOpen — which reads like a broken key, but isn't.

  1. Create the account

    Sign up at console.byteplus.com. BytePlus is Volcengine's international arm, so the console is in English and accepts international cards.

    You'll go through email confirmation and a payment-method check. Business details are not required for a personal account.

    One console holds both products you may need: ModelArk for video, Seed Speech for voices.
    One console holds both products you may need: ModelArk for video, Seed Speech for voices.

  2. Open ModelArk and create the key

    In the console go to ModelArk → API Key management → Create API Key. Give it any name — the studio doesn't care.

    The key is shown once. Copy it straight into the studio: account menu → API keys → the first field. It is stored encrypted and used only for your renders.

    ModelArk → API keys: the Create API Key button sits above the list.
    ModelArk → API keys: the Create API Key button sits above the list.

  3. Put money in — activation depends on it

    Two options, and they are not equivalent:

    • Top up the balance — pay-as-you-go, you are billed per token as you render. Simple, no commitment.
    • Buy a resource package — a block of tokens at a lower rate. Cheaper per render, but a package is tied to one model variant: a package for Seedance 2.0 does not cover 2.0 Fast, Mini or 2.5.

    Whichever you pick, this step is what makes the next one possible: model activation stays locked until the account holds a balance above $30 or a package.

    Billing center: Add credits tops the balance up; model activation unlocks from here.
    Billing center: Add credits tops the balance up; model activation unlocks from here.

  4. Activate the models

    ModelArk → Model activation. Find and enable:

    • Dreamina Seedance 2.0 — the main video model, this is what the studio shoots with by default
    • Seedream — stills for the Art Dept and character mockup sheets
    • Seedance 2.5 — optional: newer, takes up to 30s and 30 references, but costs about 1.5× more

    Activation is per model. Enabling 2.0 does not enable 2.5, and enabling the main 2.0 does not enable Fast or Mini — each is a separate switch.

    Model activation, the Media tab: each model has its own Activate switch.
    Model activation, the Media tab: each model has its own Activate switch.

  5. Shoot a cheap test

    Back in the studio: a 5-second take at 480p with no references costs about $0.35 and proves the whole chain — key, activation, billing. Do this before anything expensive.

When something doesn't work

ModelNotOpen or "this model isn't enabled on your account yet"
The key is fine — the model is not activated. Go back to step 4. If the activation button itself is unavailable, the balance requirement in step 3 hasn't been met.
401 or "invalid API key"
Either the key was copied with a stray space, or you pasted the key of a different BytePlus product. Voice sample generation uses a separate Seed Speech key — the ARK key is rejected there, and vice versa.
"Your model plan or balance is exhausted"
The package ran out or the balance hit zero. Note that BytePlus suspends the service about two hours after the balance goes negative.
The image engine works but video doesn't
Seedream is activated and Seedance isn't. They are different models with different switches on the same key.
A reference photo is rejected as "may contain real person"
Not a key problem — that is content moderation, and it refuses photorealistic humans from any source. A cartoon-styled character passes; a verified real-actor asset from the BytePlus asset library also passes.

Other keys the studio can use:

Google Gemini — backup image engine BytePlus Seed Speech — character voices fal.ai — take upscaling