Node SDK · BufferedRecorder

The default recorder buffers events in memory and flushes in batches:

const rec = es.newRecorder({ bufferSize: 2000, flushInterval: 2_000 });
// or
const rec = recorder.create(projectId, apiKey, { bufferSize: 2000 });

Options

Option	Default	Purpose
bufferSize	1000	Capacity of the in-memory event buffer.
flushSize	100	Event count that triggers an immediate flush.
flushInterval	5000	Max ms between flushes when the size threshold isn't reached.
flushTimeout	30000	Per-flush timeout (ms) for HTTP calls.
overflowPolicy	"drop-newest"	Behavior when buffer is full: "drop-newest", "block", or "error".
drainTimeout	30000	Max ms close() waits for in-flight events.
requestTimeout	10000	Per-request HTTP timeout (ms).
logger	console	Logger for diagnostics (overflow warnings, flush errors).
baseUrl	production	Override the ingestion endpoint (tests, staging).
fetch	global	Custom fetch implementation.
autoIdempotencyKey	off	Copy event.id into event.idempotencyKey when the latter is empty.

Overflow policies

"drop-newest" // drop the incoming event, log a warning (default)
"block"       // wait for space, abort signal, or close()
"error"       // throw BufferFullError

Close & flush

• close() flushes pending events and waits up to drainTimeout for the final HTTP call. It is async, so await it. Rejects with DrainTimeoutError if the deadline is hit. Call it exactly once, on the path that actually runs at shutdown.
• flush() drains buffered events at call time. Useful in tests and for graceful shutdown that needs to observe drain success.

Where close goes

A server never falls out of the bottom of its entry module, so a close() written after app.listen() runs immediately and drains an empty buffer. Hang it off the signal your process manager sends instead:

const server = app.listen(port);

async function shutdown() {
  await new Promise<void>((resolve) => server.close(() => resolve()));
  try {
    await rec.close(); // runs, and drains
  } catch (err) {
    console.error("everscribe: drain incomplete", err);
  }
  process.exit(0);
}

process.once("SIGTERM", shutdown);
process.once("SIGINT", shutdown);

Stop the server first, then close the recorder: events recorded by in-flight requests have to reach the buffer before it drains. And because close() is async, process.on("exit") is not a place to call it. That handler only runs synchronous work, so the drain never gets awaited and the buffer is discarded.