Inference service tiers

Service tiers select the serving capacity and pricing for a Telnyx-hosted model. Set service_tier on each request and keep the same public model ID.

Choose a tier

Tier	Request value	When to use it
Flex	`flex`	Cost-sensitive work that can tolerate higher latency and variable availability, such as offline evaluation, document processing, and background summarization
Default	`default`	General-purpose inference with standard pricing
Priority	`priority`	Interactive applications where lower latency is more important than the lowest token price

For standard Inference API requests, omitting service_tier uses default. Flex and Priority are available only on select models. A tier does not change the model’s capabilities or context window, and selecting Priority does not guarantee a fixed response time. Flex uses the same request APIs as the other tiers. A background workload sends individual requests; selecting Flex does not create an asynchronous batch job.

Check model support

Call Get available models (GET /v2/ai/openai/models) and inspect data[].service_tiers for the desired model. Send one of those values as service_tier.

curl https://api.telnyx.com/v2/ai/openai/models \
  -H "Authorization: Bearer $TELNYX_API_KEY"

Use the returned public id unchanged. Do not append a tier suffix to the model name. Model support can change, so check the catalog before choosing Flex or Priority. The service_tiers field is omitted for externally hosted models; their provider determines supported tiers and behavior.

Set the tier on a request

Chat Completions

After confirming that deepseek-ai/DeepSeek-V4.1-Flash lists flex, send this body to Chat Completions (POST /v2/ai/openai/chat/completions):

{
  "model": "deepseek-ai/DeepSeek-V4.1-Flash",
  "service_tier": "flex",
  "messages": [
    {
      "role": "user",
      "content": "Summarize this support note in one sentence: The customer could not sign in. Resetting the password restored access."
    }
  ]
}

To use Default or Priority, set service_tier to default or priority and choose a model that advertises that tier. Streaming requests select the tier with the same field.

Responses

The Responses API (POST /v2/ai/openai/responses) accepts the same top-level field:

{
  "model": "deepseek-ai/DeepSeek-V4.1-Flash",
  "service_tier": "flex",
  "input": "Summarize this support note in one sentence: The customer could not sign in. Resetting the password restored access."
}

Handle unavailable capacity

A supported tier can still be temporarily unavailable. For Flex workloads, allow a longer request timeout and use bounded retries with exponential backoff and jitter for transient capacity errors. Honor Retry-After when present. If the model does not support the requested tier, select a value advertised by the models endpoint instead of retrying the unchanged request. Do not rely on automatic switching to another tier. An application can explicitly retry on another supported tier if its latency requirements and budget permit; that new request uses the newly selected tier’s rates.

Pricing

Input, cached input, and output token rates depend on both the model and service tier. Compare the applicable rates on the Inference pricing page. See Pricing and billing units for the billing basis of other Inference services.

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Inference service tiers

Choose a tier

Check model support

Set the tier on a request

Chat Completions

Responses

Handle unavailable capacity

Pricing

​Choose a tier

​Check model support

​Set the tier on a request

​Chat Completions

​Responses

​Handle unavailable capacity

​Pricing

Choose a tier

Check model support

Set the tier on a request

Chat Completions

Responses

Handle unavailable capacity

Pricing