Limits

Soft limits are adjustable through AWS Support; hard ones are not. Several defaults are lower in some regions — check the AWS IoT Core quotas page for the deployment’s region before designing against a number.

AWS limits

Limit	Value	S/H	Notes
Concurrent connections per account	500,000	S
Subscriptions per connection	50	S	Binds an app holding many, not a node
Topic subscriptions per SUBSCRIBE	8	H	A node with many subgroups splits its subscribe
MQTT payload	128 KB	H	One params publish, node config, or timeseries batch
Shadow document	8 KB	H	Whole reported state; grows with device/param count
Shadow JSON depth	8	H	state.reported.params.<device>.<param> is 5
Shadow name	64 B	H	params-<group>[-<sub>…] is ≤25 B — why ids are short
Topic slashes	7	H	.../groups/<g>/subgroups/<s>/control uses 6. Basic Ingest’s $aws/rules/<rule>/ prefix is exempt
Thing name	128 B	H	Node IDs are 36-char UUIDs
Indexable thing attributes (no thing type)	3	H	Things are created without a thing type, so 3 applies — not 50. group_id uses one
Thing groups per thing	10	H	Admin groups only
Thing group hierarchy depth	7	H
Direct child groups per thing group	100	H
Dynamic thing groups per account	100	S
QoS 1 retry duration	1 h	H	How long a getGroupInfo push to an offline node stays queued; past it the node recovers via its startup request
Unacked outbound publishes per client	100	H
In-flight shadow messages per thing	10	H
Rules per account / actions per rule	1000 / 10	S / H	This deployment defines 5 rules, 1–2 actions each
Inline session policy (STS AssumeRole)	2048 chars	H	≈4 groups or 8 shared subgroups per user — see below

ESP RainMaker Neo limits

Limit	Value	Notes
Main groups per node	1	A second association moves the node: old group unlinked, shadow, group_id attribute and user tags migrated. See node_assoc.md
Subgroups per node	3	subgrp1/subgrp2/subgrp3 slots; a fourth add is rejected with "node is already in 3 subgroups"
Subgroups per group, nodes per group	unbounded	Only subgroups shared to a user cost session-policy budget
Full-access groups per MQTT session	4	Consequence of the 2048-char session policy; exceeding it fails credential issuance outright. See user_auth.md §3.3, group.md
Shared subgroups per MQTT session	~8	Same budget, cheaper per entry
Sharing request validity	24 h	From creation
Association request validity	5 min	DynamoDB TTL and a deadline the handlers enforce on read, since TTL deletion is only guaranteed within ~48 h. Refreshed on each status update, so the Matter verify → confirm leg gets a fresh 5 min. See node_assoc.md
Node IDs per claimant	20	Lifetime cap, operator-configurable; reservations are never deleted, so a removed node does not return its slot. See assisted-claiming.md