Client-side pixels fail silently. You miss a parameter, and the browser simply shrugs.

The Conversions API is not so forgiving.

When your backend sends an invalid JSON payload to https://bzr.openai.com/v1/events, OpenAI does not silently ignore it. The server immediately returns an explicit HTTP 400 Bad Request error. If your UNIX timestamp is off by more than seven days, the event is rejected. If your currency code is lowercase (usd instead of USD), the payload fails validation. If your customer email is not lowercased before SHA-256 hashing, match rates collapse.

Diagnosing CAPI failures requires understanding exactly what OpenAI ingest API expects down to the byte.

Here is the complete reference guide to debugging CAPI error codes, resolving payload rejection issues, and enforcing timestamp integrity.

1. Quick Reference: Common CAPI HTTP Status Codes

When sending POST requests to https://bzr.openai.com/v1/events?pid=<PIXEL-ID>, the API responds with standardized HTTP status codes:

HTTP Status	Meaning	Typical Root Cause	Immediate Action
200 OK	Success / Validated	Valid payload accepted or validation check passed	If `validate_only: true`, switch to `false` for production
400 Bad Request	Schema / Parameter Failure	Missing required fields, invalid timestamp, float amounts	Inspect response body error details and validate payload shape
401 Unauthorized	Authentication Failed	Invalid, revoked, or missing Bearer token in header	Re-issue CAPI key in Ads Manager; verify header format
403 Forbidden	Access Denied	Pixel ID mismatch or ad account permissions revoked	Verify `pid` query parameter matches the pixel owning the key
429 Too Many Requests	Rate Limit Exceeded	Burst requests exceeded account throughput thresholds	Implement exponential backoff and batching (up to 1,000 events)
500 / 503	Server Error	Temporary endpoint degradation or gateway timeout	Retry with jittered exponential backoff; check OpenAI status

2. Diagnosing 400 Bad Request: Root Causes & Solutions

A 400 Bad Request indicates that your JSON body violates the expected CAPI contract. Below are the most frequent causes observed in production implementations.

Issue A: Floating-Point Amounts Instead of Integer Minor Units

OpenAI Ads strictly adheres to ISO 4217 minor units for all monetary fields (amount). Sending floats such as 89.99 triggers a validation error.

// INCORRECT (Triggers 400 Bad Request)
{
  "amount": 89.99,
  "currency": "USD"
}

// CORRECT (Integer Minor Units: 89.99 USD = 8999 cents)
{
  "amount": 8999,
  "currency": "USD"
}

Rule: Multiply standard decimal currency by 100 for currencies with 2 decimal places (USD, EUR, GBP, CAD, AUD). For zero-decimal currencies like JPY, use the exact integer value without multiplication.

Issue B: Expired or Future Timestamps (`timestamp_ms`)

OpenAI Ads requires every event to supply a timestamp_ms representing milliseconds since the Unix epoch (e.g., Date.now()).

Maximum Past Age: 7 days (604,800,000 ms). Any event with a timestamp older than 7 days is rejected.
Future Timestamps: Events timestamped more than 5 minutes into the future (due to server clock skew) will be rejected.

// Validating timestamp before dispatch
const now = Date.now();
const SEVEN_DAYS_MS = 7 * 24 * 60 * 60 * 1000;

if (event.timestamp_ms < (now - SEVEN_DAYS_MS)) {
  console.error("Event rejected: Timestamp is older than 7 days allowed window.");
  return;
}

Issue C: Unrecognized or Misspelled Event Types

OpenAI Ads supports designated standard events. Using non-standard casing or invalid names will trigger a schema error unless explicitly declared as a custom event.

Supported Standard Event Types:

page_viewed
contents_viewed
items_added
checkout_started
order_created
lead_created
appointment_scheduled
registration_completed
trial_started
subscription_activated
app_installed (Server CAPI only)
app_opened (Server CAPI only)

If you are tracking an action outside standard events, you must set "type": "custom" and include a custom event identifier in the data payload.

3. The Correct CAPI Payload Architecture

To eliminate schema validation errors, format your batch request exactly as shown below:

{
  "validate_only": false,
  "events": [
    {
      "id": "evt_order_108429_1725148800",
      "type": "order_created",
      "timestamp_ms": 1725148800000,
      "action_source": "website",
      "event_id": "shopify_order_601928374",
      "user_data": {
        "em": "f660ab912ec121d1b1e928a0bb4bc61b15f5ad44d5efdc4e1c92a25e99b8e44a",
        "ph": "94212953e5e49f579d479cb2c9f417f7b15d914d33a682ff9341496695222718",
        "client_ip_address": "198.51.100.42",
        "client_user_agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7)..."
      },
      "data": {
        "amount": 14500,
        "currency": "USD",
        "order_id": "108429",
        "contents": [
          {
            "content_id": "SKU-9921",
            "quantity": 1,
            "item_price": 14500
          }
        ]
      }
    }
  ]
}

4. Testing with `validate_only: true`

Before pushing new backend event handlers or queue workers to production, test them with a curl command using validate_only: true:

curl -X POST "https://bzr.openai.com/v1/events?pid=YOUR_PIXEL_ID" \
  -H "Authorization: Bearer YOUR_CAPI_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "validate_only": true,
    "events": [
      {
        "id": "test_evt_001",
        "type": "order_created",
        "timestamp_ms": '"$(date +%s%3N)"',
        "action_source": "website",
        "event_id": "test_order_dedup_001",
        "data": {
          "amount": 2500,
          "currency": "USD",
          "order_id": "TEST-101"
        }
      }
    ]
  }'

If the payload is valid, OpenAI returns {"success": true} with HTTP 200. If any property is invalid, the response body details the exact JSON pointer and validation rule that failed.

5. Ensuring Deduplication Across Browser and Server

When firing both the browser pixel (oaiq) and server-side CAPI for the same user event (such as order_created), deduplication is mandatory to avoid double-counting conversions.

Shared Event ID: Generate a unique identifier on your server or checkout session (e.g., checkout_token or order_id).
Client-Side Emission: Pass the identifier into the browser pixel payload as event_id.
Server-Side Emission: Pass the exact same string into the CAPI event object as event_id.
Attribution Engine Deduplication: OpenAI Ads de-duplicates matching events received within a 48-hour window, merging server match quality data with browser session context.

For an end-to-end guide on deduplication mechanics, refer to our guide on deduplicating OpenAI Ads pixel and CAPI events.

6. Resolving Persistent Payload Errors

If your server continues to experience dropped events or unexplained payload rejections:

Verify that user data fields (em, ph) are strictly SHA-256 hashed and lowercase (see our user data hashing guide).
Confirm your server clock is synchronized via NTP to eliminate clock drift errors.
Ensure your worker queues do not re-try failed events after the 7-day timestamp threshold has elapsed.

If your team needs guaranteed zero-loss server tracking with full schema validation and deduplication, explore our Conversions API Setup service or book a Tracking Audit.