Pipelines API Reference

Pipeline Binding Interface

// From @cloudflare/workers-types
interface Pipeline {
  send(data: object | object[]): Promise<void>;
}

interface Env {
  STREAM: Pipeline;
}

  async fetch(request: Request, env: Env): Promise {
    // send() returns Promise<void> - no result data
    await env.STREAM.send([event]);
    return new Response('OK');
  }
} satisfies ExportedHandler;

Key points:

• send() accepts single object or array
• Always returns Promise<void> (no confirmation data)
• Throws on network/validation errors (wrap in try/catch)
• Use ctx.waitUntil() for fire-and-forget pattern

Writing Events

Single Event

await env.STREAM.send([{
  user_id: "12345",
  event_type: "purchase",
  product_id: "widget-001",
  amount: 29.99
}]);

Batch Events

const events = [
  { user_id: "user1", event_type: "view" },
  { user_id: "user2", event_type: "purchase", amount: 50 }
];
await env.STREAM.send(events);

Limits:

• Max 1 MB per request
• 5 MB/s per stream

Fire-and-Forget Pattern

  async fetch(request: Request, env: Env, ctx: ExecutionContext): Promise {
    const event = { /* ... */ };
    
    // Don't block response on send
    ctx.waitUntil(env.STREAM.send([event]));
    
    return new Response('OK');
  }
};

Error Handling

try {
  await env.STREAM.send([event]);
} catch (error) {
  console.error('Pipeline send failed:', error);
  // Log to another system, retry, or return error response
  return new Response('Failed to track event', { status: 500 });
}

HTTP Ingest API

Endpoint Format

https://{stream-id}.ingest.cloudflare.com

Get {stream-id} from: npx wrangler pipelines streams list

Request Format

CRITICAL: Must send array, not single object

# ✅ Correct
curl -X POST https://{stream-id}.ingest.cloudflare.com \\
  -H "Content-Type: application/json" \\
  -d '[{"user_id": "123", "event_type": "purchase"}]'

# ❌ Wrong - will fail
curl -X POST https://{stream-id}.ingest.cloudflare.com \\
  -H "Content-Type: application/json" \\
  -d '{"user_id": "123", "event_type": "purchase"}'

Authentication

curl -X POST https://{stream-id}.ingest.cloudflare.com \\
  -H "Content-Type: application/json" \\
  -H "Authorization: Bearer YOUR_API_TOKEN" \\
  -d '[{"event": "data"}]'

Required permission: Workers Pipeline Send

Create token: Dashboard → Workers → API tokens → Create with Pipeline Send permission

Response Codes

SQL Functions Quick Reference

Available in INSERT INTO sink SELECT ... FROM stream transformations:

String types for CAST: string, int32, int64, float32, float64, bool, timestamp

Full reference: Pipelines SQL Reference

SQL Transform Examples

Filter Events

INSERT INTO my_sink
SELECT * FROM my_stream
WHERE event_type = 'purchase' AND amount > 100

Select Specific Fields

INSERT INTO my_sink
SELECT user_id, event_type, timestamp, amount
FROM my_stream

Transform and Enrich

INSERT INTO my_sink
SELECT
  user_id,
  UPPER(event_type) as event_type,
  timestamp,
  amount * 1.1 as amount_with_tax,
  CONCAT(user_id, '_', product_id) as unique_key,
  CASE
    WHEN amount > 1000 THEN 'high_value'
    WHEN amount > 100 THEN 'medium_value'
    ELSE 'low_value'
  END as customer_tier
FROM my_stream
WHERE event_type IN ('purchase', 'refund')

Querying Results (R2 Data Catalog)

npx wrangler r2 sql query "warehouse_name" "
SELECT 
  event_type,
  COUNT(*) as event_count,
  SUM(amount) as total_revenue
FROM default.my_table
WHERE event_type = 'purchase'
  AND timestamp >= '2025-01-01'
GROUP BY event_type
ORDER BY total_revenue DESC
LIMIT 100"

Note: Iceberg tables support standard SQL queries with GROUP BY, JOINs, WHERE, ORDER BY, etc.