Janus Client SDK

A lightweight JavaScript library for tracking events from web applications. Automatically handles batching, retries, rate limiting, and persistence.

Lightweight (~3KB)Auto RetryBatchingPersistence

HTTP API

Authentication#

Authenticate requests with your API key using either header format:

bash

# Option 1: x-api-key header
curl -H "x-api-key: jns_your_api_key" ...

# Option 2: Bearer token
curl -H "Authorization: Bearer jns_your_api_key" ...

Send Events#

POST a single event object or an array of events to the events endpoint.

Single Event#

bash

curl -X POST https://api.addjanus.ca/api/v1/events \
  -H "Content-Type: application/json" \
  -H "x-api-key: jns_your_api_key" \
  -d '{
    "type": "purchase_completed",
    "payload": { "orderId": "ORD-123", "amount": 99.99 },
    "distinctId": "user_456",
    "timestamp": "2026-03-05T12:00:00.000Z"
  }'

Response (201)

{
  "id": "clx...",
  "userId": "...",
  "type": "purchase_completed",
  "payload": { "orderId": "ORD-123", "amount": 99.99 },
  "distinctId": "user_456",
  "context": { "country": "CA" },
  "timestamp": "2026-03-05T12:00:00.000Z",
  "createdAt": "2026-03-05T12:00:01.000Z"
}

Batch Events#

Send an array instead of a single object:

bash

curl -X POST https://api.addjanus.ca/api/v1/events \
  -H "Content-Type: application/json" \
  -H "x-api-key: jns_your_api_key" \
  -d '[
    { "type": "page_view", "payload": { "path": "/pricing" }, "distinctId": "user_456" },
    { "type": "button_click", "payload": { "id": "cta" }, "distinctId": "user_456" }
  ]'

Response (201)

{ "count": 2 }

Event Schema#

Field	Type	Required	Description
type	string	Yes	Event name
payload	object	No	Event properties (JSON object, 10KB combined limit with context)
tags	string[]	No	Array of string tags (max 10, each max 100 chars)
distinctId	string	No	User identifier
sessionId	string	No	Session identifier
context	object	No	Additional context (JSON object, 10KB combined limit with payload; country auto-added server-side)
timestamp	ISO 8601	No	Event time (defaults to server time)

Error Handling#

HTTP status codes returned by the events endpoint:

Status	Meaning	Action
201	Event(s) created	—
401	Invalid or missing API key	Check your x-api-key header and key value
403	Origin not allowed	Add your domain to the key's allowed origins in Settings
429	Rate limited or monthly cap exceeded	Back off and retry; check Retry-After header

API Reference Automatic Page Tracking

Need Help?

If you have questions or run into issues, check out our troubleshooting guide or reach out to our support team.

Troubleshooting Guide