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Meter features are the most powerful feature type in Fluxrate. They combine usage tracking with entitlement enforcement, letting you both bill for usage and gate access when limits are hit.

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How Meter Features Work

When you create a meter feature, Fluxrate automatically creates:
  1. A Feature (the entitlement definition)
  2. A corresponding Meter (the usage tracking engine)
The meter has a unique meter_token that your backend uses to send usage events.

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Creating a Meter Feature

  1. Go to Features in the sidebar
  2. Click Add Feature
  3. Select Meter as the type
  4. Configure the meter settings and click Create

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Request Fields

FieldRequiredDescription
name✅Display name for the feature
lookup_key✅Unique identifier (slug) for this feature
meter_name✅Internal meter identifier (must be unique per org)
property_name✅The event payload property to read for aggregation
aggregation_type✅How to aggregate: SUM, MAX, UNIQUE_COUNT, LAST
unitDisplay unit (e.g., “calls”, “GB”, “tokens”)
descriptionHuman-readable description

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Aggregation Types

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SUM

Adds up all values received in the billing period. Best for: API calls, data transferred, messages sent, compute minutes. 
// Events
{ "property_name": "1" }  // call 1
{ "property_name": "1" }  // call 2
{ "property_name": "5" }  // bulk operation

// Result: SUM = 7

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MAX

Takes the highest single value observed during the period. Best for: Peak concurrent connections, high-water mark measurements. 
// Events
{ "property_name": "10" }  // 10 concurrent connections
{ "property_name": "25" }  // peak: 25
{ "property_name": "15" }

// Result: MAX = 25

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UNIQUE_COUNT

Counts the number of distinct values of a property. Best for: Monthly active users, unique devices, distinct API consumers. 
// Events (counting unique user_ids)
{ "user_id": "user_a" }
{ "user_id": "user_b" }
{ "user_id": "user_a" }  // duplicate - not counted again

// Result: UNIQUE_COUNT = 2
For UNIQUE_COUNT meters, send the value to count as the metadata.user_id field. The SDK endpoint handles this mapping automatically.

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LAST

Takes the most recent value received. Best for: Current storage usage, current seat count (snapshot billing). 
// Events received over time
{ "property_name": "50" }  // at 10:00
{ "property_name": "75" }  // at 14:00
{ "property_name": "60" }  // at 18:00

// Result: LAST = 60

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Usage Filters

Meter features support filters to segment events. For example, track API calls only from specific regions or versions: 
curl -X POST https://api.fluxrate.co/api/v1/features \
  -H "Content-Type: application/json" \
  -H "Cookie: access_token=<token>" \
  -d '{
    "name": "Premium API Calls",
    "lookup_key": "premium_api_calls",
    "type": "meter",
    "meter_name": "premium_api_calls",
    "property_name": "call_count",
    "aggregation_type": "SUM",
    "filters": [
      {
        "key": "tier",
        "values": ["premium", "enterprise"]
      }
    ]
  }'

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Filter Rules

  • Maximum 5 filters per meter
  • Each filter supports up to 15 values
  • Values are matched exactly (strings)
  • Filter keys cannot be added or removed after creation — only values can be updated

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Setting Entitlement Limits

When attaching a meter feature to a plan, configure the usage limit: 
# Unlimited usage
{
  "feature_id": "<feature_id>",
  "is_enabled": true,
  "is_unlimited": true
}

# Limited usage
{
  "feature_id": "<feature_id>",
  "is_enabled": true,
  "usage_limit": 10000,
  "usage_reset_period": "month",
  "is_soft_limit": false
}
OptionDescription
is_unlimited: trueNo usage cap — just track and bill
usage_limitMaximum units allowed in usage_reset_period
usage_reset_periodWhen the counter resets: day, week, month, year
is_soft_limittrue = warn but don’t block; false = hard block at limit
Use soft limits in SaaS products where you want to upsell users who exceed their plan, rather than hard-blocking them.