Rate Limits

Limits are enforced at two levels: per profile and per device. Defaults vary by plan. Exceeding a limit returns ACK|ERR|rate_limited (or HTTP 429).

RPM = requests per minute.

Per profile

Resource	Transports	Scale	Starter	Free
Uplink RPM (PUSH)	UDP, TCP, HTTP, MQTT	1,000	500	60
Downlink RPM (PULL)	UDP, TCP, HTTP, MQTT	1,000	500	60
Command RPM	MQTT	1,000	500	60
Connections per IP	TCP, HTTP, MQTT	20	10	3

Per device

Resource	Transports	Scale	Starter	Free
Max payload size	UDP, TCP, HTTP, MQTT	100 KB	100 KB	100 KB
Connection TTL	TCP, MQTT	15 s	10 s	10 s
Keep-alive idle timeout	TCP, MQTT	5 s	5 s	5 s

Connection TTL vs Keep-alive idle timeout

These two TCP limits serve different purposes:

• Connection TTL is a hard cap on total connection duration. No matter how active the device is, the server closes the connection after this period and sends ACK|ERR|ttl_expired. The device should reconnect.
• Keep-alive idle timeout is the maximum silence between frames. If the device stops sending data for this long, the server closes the connection with ACK|ERR|keep_alive_timeout. Sending any frame (including PING) resets the timer.

Both timers start when the connection is accepted. TTL counts total elapsed time; keep-alive resets on every received frame.

Error and close responses

Condition	Raw ACK	HTTP Status
RPM exceeded	ACK|ERR|rate_limited	429
Payload too large	ACK|ERR|payload_too_large	413
Per-IP connections exceeded	ACK|ERR|rate_limited (then close)	429 (then close)
Connection TTL exceeded	ACK|ERR|ttl_expired (then close)	N/A
Keep-alive idle timeout	ACK|ERR|keep_alive_timeout (then close)	N/A

PING is exempt from rate limiting on TCP and UDP. On HTTP, HEAD counts toward the uplink RPM. On MQTT, keepalive is handled natively by PINGREQ/PINGRESP.

See each transport page for transport-specific limits.