What is a deployment shape, and why did my deployment fail to create?

A deployment shape is a pre-validated, pre-configured deployment template. It bundles a known-good combination of GPU type and count, precision, and serving parameters, optimized for speed (fast), cost per token at scale (throughput), or lowest cost (minimal). A deployment created from a shape starts from a configuration that is known to work for that model.

Why deployments created without a shape often fail

If you create a deployment without a shape — that is, without passing --deployment-shape (or deploymentShape in the API) — the configuration is not validated ahead of time. Mistakes only surface at creation, where they cause failures. Common examples:

A GPU count that cannot fit the model in memory
A context length the configuration can’t serve
A quantization or precision the model doesn’t support on that hardware

Deployments created without a shape fail far more often than deployments created from a shape — they are the most common cause of failed deployment creations on Fireworks. Do not create deployments without a shape; the unshaped path may be deprecated in the future.

How to find and use a shape

firectl
REST API
Web UI

List the shapes available for your model:

firectl deployment-shape-version list --base-model accounts/fireworks/models/gpt-oss-120b

Then pass the shape’s name to --deployment-shape when creating the deployment:

firectl deployment create accounts/fireworks/models/gpt-oss-120b \
  --deployment-shape accounts/fireworks/deploymentShapes/gpt-oss-120b-fast

Call List Deployment Shape Versions to find shapes for your model, then pass the shape name as deploymentShape in the Create Deployment request body:

curl -X POST "https://api.fireworks.ai/v1/accounts/YOUR_ACCOUNT_ID/deployments" \
  -H "Authorization: Bearer $FIREWORKS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "baseModel": "accounts/fireworks/models/gpt-oss-120b",
    "deploymentShape": "accounts/fireworks/deploymentShapes/gpt-oss-120b-fast"
  }'

If no shape fits

If you need a configuration that no existing shape covers, contact us — we’ll help you find the right shape or add one for your workload.

Reference

Examples

FAQ

What is a deployment shape, and why did my deployment fail to create?

Why deployments created without a shape often fail

How to find and use a shape

If no shape fits

​Why deployments created without a shape often fail

​How to find and use a shape

​If no shape fits

Why deployments created without a shape often fail

How to find and use a shape

If no shape fits