Data requirements and limits for custom event data

You can report custom events to New Relic in several ways, including the New Relic Event API, APM agent APIs, Browser agent APIs, and the Mobile SDK.

This document contains general requirements and rules for inserting and using custom events and their associated attributes. Additional requirements may apply based on the method you use.

General requirements

How long custom data is retained depends on your Insights subscription and its associated data retention.

When reporting custom events and attributes, follow these general requirements for supported data types, naming syntax, and size:

Requirement Description

Total maximum size or length: 1MB (10^6 bytes) maximum per POST. We highly recommend using compression.

The payload must be encoded as UTF-8.

The Event API has additional HTTP rate limits.

Attribute data types

Attribute values can be either a string or a numeric integer or float.

If your attribute values contain date information, define it as an unformatted Unix timestamp (in seconds or milliseconds) by using the Insights data formatter.

Attribute size

Maximum name size: 255 bytes.

Maximum attribute value size:

  • Custom attributes sent by the agent: 255 bytes
  • Attributes attached to custom events sent using the Event API: 4096 characters

    Charts may only display the first 255 characters of attribute values. For complete attribute values, use the JSON chart type or Query API.

Maximum total attributes per event: 254. Exception: If you use an APM agent API, the max is 64.

Maximum total attributes per event type: 48,000.

Naming syntax

Attribute names can be a combination of alphanumeric characters, colons (:), periods (.), and underscores (_).

Event types (using the eventType attribute) can be a combination of alphanumeric characters, colons (:), and underscores (_).

Do not use words reserved for use by NRQL.

Null values The database does not store any data with a null value.

Reserved words

Avoid using the following reserved words as names for events and attributes. Otherwise, unexpected results may occur.

This is not a complete list. In general, it's a good practice to avoid using MySQL-reserved words to avoid collision with future New Relic functionality.

Keyword Description

This is a reserved attribute name. If it's included, it will be dropped during ingest.


Value must be an integer. If it is not an integer, the attribute name and value will be dropped during ingest.


The event type as stored in New Relic. New Relic agents and scripts normally report this as eventType. Can be a combination of alphanumeric characters, colons (:), and underscores (_). Be sure to review the prohibited eventType values and eventType limits.

Prohibited eventType values

For your eventType value, avoid using:

  • Metric, MetricRaw, and strings prefixed with Metric[0-9] (such as Metric2 or Metric1Minute).
  • Public_ and strings prefixed with Public_.

These event types are reserved for use by New Relic. Events passed in with these eventType values will be dropped.


Must be a Unix epoch timestamp. You can define timestamps either in seconds or in milliseconds. It must be +/-1 day (24 hours) of the current time on the server.

Log forwarding terms The following keys are reserved by the Infrastructure agent's log forwarding feature: entity.guid, log, hostname, plugin.type, fb.input. If used, they are dropped during ingest and a warning is added to the logs.
NRQL syntax terms

If you need to use NRQL syntax terms as attribute names, including dotted attributes, they must be enclosed in backticks; for example, `LIMIT` or `consumer.offset`. Otherwise, avoid using these reserved words:

ago, and, as, auto,

begin, begintime,


day, days,

end, endtime, explain,

facet, from,

hour, hours,

in, is,

like, limit,

minute, minutes, month, months,

not, null,

offset, or,


second, seconds, select, since,



week, weeks, where, with

Additional Browser PageAction requirements

For additional requirements for using New Relic Browser's custom PageAction event, see Insert custom data via New Relic Browser agent.

Additional Event API requirements

For more requirements and details for the Event API, see Event API.

Event type limits

The current limit for total number of eventType values is 250 per sub-account in a given 24-hour time period. If a user exceeds this limit, New Relic may filter or drop data. Event types include:

  • Default events from New Relic agents
  • Custom events from New Relic agents
  • Custom events from Insights custom event inserter

For more help

If you need more help, check out these support and learning resources: