Builds the cohort table from the events you pass
Builds the cohort table from the events you pass: users grouped by the period of their first event, counted again in each following period. Returns the table per cohort, a retention curve across all cohorts, and, where events carry a value, cumulative value and value per user. The curve counts only cohorts old enough for a given period, so a young cohort is not scored as churn. Day, week and month are real calendar periods. Nothing is fetched, nothing is stored.
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
POST https://tools.halowerk.com/v1/cohort/retention
| Category | Everything else |
|---|---|
| Provider host | tools.halowerk.com |
| Networks | eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 3 from 3 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-10-10 | valid payment request | 402 | $0.002 | 903 ms |
Example input (from the provider)
{
"body": {
"events": [
{
"time_unix_s": 1785110400,
"type": "order",
"user_id": "u1",
"value": 19.9
},
{
"time_unix_s": 1785715200,
"type": "order",
"user_id": "u1",
"value": 24.5
},
{
"time_unix_s": 1785110400,
"type": "order",
"user_id": "u2",
"value": 12
},
{
"time_unix_s": 1785715200,
"type": "order",
"user_id": "u3",
"value": 30
}
],
"period": "week",
"periods": 3
},
"bodyType": "json",
"method": "POST",
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"properties": {
"activation_type": {
"description": "If set, only events of this type put a user into a cohort. Without it the first event of any type counts.",
"maxLength": 120,
"type": "string"
},
"events": {
"description": "Each event needs user_id and a timestamp (time_unix_s in seconds since 1970, or time as ISO 8601). Optional: type and value. Any other field name is rejected rather than guessed. The service caps the whole request body at 256 KB, so long records reach that limit before maxItems.",
"maxItems": 4000,
"minItems": 1,
"type": "array"
},
"period": {
"default": "week",
"enum": [
"day",
"week",
"month"
],
"type": "string"
},
"periods": {
"default": 12,
"description": "How many periods the table runs, period 0 being the entry period.",
"maximum": 52,
"minimum": 1,
"type": "integer"
},
"retention_types": {
"description": "If set, only events of these types count as being active. Without it every event counts.",
"items": {
"type": "string"
},
"maxItems": 50,
"type": "array"
},
"timezone_offset_s": {
"default": 0,
"description": "Offset from UTC in seconds used to place period boundaries.",
"maximum": 50400,
"minimum": -50400,
"type": "integer"
},
"week_start": {
"default": "monday",
"enum": [
"monday",
"sunday"
],
"type": "string"
}
},
"required": [
"events"
],
"type": "object"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}