Limiter Processor

Overview

The Limiter processor applies rate limiting to manage API traffic and ensure quotas are not exceeded. For example, you can define a quota for API usage and limit the number of requests allowed per user or service. If the quota is reached, the traffic is throttled or rejected.

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Input and Output

This processor operates within the request stream and determines whether a request is within the allowed limits:

• Input Stream: Request – Receives incoming requests before they are processed further.

• Output Streams: Request -

  • Below Limit – If the Request is within the defined quota, it continues through the request stream.

  • Above Limit – If the Request exceeds the quota, it follows a separate path, which may result in throttling, rejection, or queuing based on the flow configuration.

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Parameters

Each parameter is defined as a key-value pair inside the parameters section.

quota_id

Type: string
Required: True
Defines the ID of the quota or internal limit to be used for rate limiting. For more details about Lunar.dev Quotas check out the Quota Overview page.

Example:

- key: quota_id
  value: "MyQuota"

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Best Practices

• Ensure quota_id matches a valid quota resource.

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Limiter Processor Template

Custom Metrics Processors

  Limiter: # Limit API Requests 
    processor: Limiter
    parameters:
      - key: quota_id
        value: MyQuota # The quota allotment used to limit requests to the API Provider

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Use Case

Limit premium users to 1,000 API calls per day. If they exceed the limit, subsequent requests are blocked.

Limiter:
  processor: Limiter
  parameters:
    - key: quota_id
      value: OpenAIQuota

quotas:
  - id: OpenAIQuota
    filter:
      url: api.openai.com/* 
    strategy:
      fixed_window:
        max: 10000
        interval: 1
        interval_unit: day

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For more details on configuring flows, visit the Lunar.dev Flows Documentation.