Reconnect & backpressure

Both WebSocket and gRPC eventually drop. This page is the playbook for keeping a stream healthy in production.

Reconnect

The pattern that works:

Detect the close. WS: 'close' event. gRPC: stream 'end' or 'error'.
Wait with exponential backoff. Start at 1 second, double each retry, cap at 60 seconds.
Reconnect. Reset the backoff to 1 second on a successful connect.
Re-send your subscriptions. They are not persisted across reconnects.
Fill the gap with REST. From the timestamp of your last good event, query /api/v1/candles?start=... or /swaps/range?start=... for the missing window. We do not replay missed events on the stream.

Backpressure

If your client is slower than the message rate, the server’s send buffer fills up. When it overflows, you get disconnected with an error indicating overflow. To stay under:

Don’t await heavy work in the receive loop. Push events into an in-memory queue and process them on a separate worker.
Coalesce. If you’re rendering a chart, you usually only need the latest event per pool per frame, not every event.
Filter aggressively. Subscribe with the narrowest filter you can — a pools filter is much cheaper than no filter.

Keepalive

WebSocket: send { "type": "ping" } every 30 seconds. The server replies with { "type": "pong" }. If you don’t see a pong within ~10 seconds, treat it like a disconnect. gRPC: configure HTTP/2 keepalive on the channel:

const client = new proto.dexploit.v1.PriceStream(ENDPOINT, creds, {
  'grpc.keepalive_time_ms': 30_000,
  'grpc.keepalive_timeout_ms': 10_000,
  'grpc.keepalive_permit_without_calls': 1,
});

Without these, half-open TCP hangs (firewall idle-timeouts, NAT drops, ungraceful peer crashes) look like the stream stalled — your client thinks it’s connected but no events arrive. The keepalive ping forces the OS to surface the dead connection so your reconnect logic can fire.

Common failure modes

Symptom	Likely cause	Fix
Stream silently stalls, no events for minutes	Half-open TCP	Configure keepalive (above).
Reconnect succeeds but no events	Forgot to re-subscribe	Re-send your subscribe message after every connect.
Events stop after a key rotation	Using the old key	Update your client to the new key; old key works for 7 days during grace, then 401s mid-stream.
Constant disconnects under load	Backpressure overflow	Move work off the receive loop or filter more narrowly.
429 immediately on connect	Free-tier rate limit on connections	Add backoff or upgrade.

Getting started

Concepts

Streaming

Examples

Reconnect & backpressure

Reconnect

Backpressure

Keepalive

Common failure modes

​Reconnect

​Backpressure

​Keepalive

​Common failure modes

Reconnect

Backpressure

Keepalive

Common failure modes