Limits

This reference article explains the pricing-based and system-wide limits and requirements imposed by Axiom.

Axiom applies certain limits and requirements to guarantee good service across the platform. Some of these limits depend on your pricing plan, and some of them are applied system-wide. This reference article explains all limits and requirements applied by Axiom.

Limits are necessary to prevent potential issues that could arise from the ingestion of excessively large events or data structures that are too complex. Limits help maintain system performance, allow for effective data processing, and manage resources effectively.

Pricing-based limits

The table below summarizes the limits applied to each pricing plan. For more details on pricing and contact information, see the Axiom pricing page.

	Personal	Axiom Cloud
Always Free storage	25 GB	100 GB
Always Free data loading	500 GB / month	1,000 GB / month
Always Free query compute	10 GB-hours / month	100 GB-hours / month
Maximum data loading	500 GB / month	–
Maximum data retention	30 days	Custom
Datasets	2	100 *
Fields per dataset	256	1,024 *
Users	1	1,000 *
Monitors	3	500 *
Notifiers	Email, Discord	All supported
Supported edge deployments	US	US

* Soft limit that can be increased upon request.

If you’re on the Axiom Cloud plan and you exceed the Always Free allowances outlined above, additional charges apply based on your usage above the allowance. For more information, see the Axiom pricing page.

All plans include unlimited bandwidth, API access, and data sources subject to the Fair Use Policy.

To see how much of your allowance each dataset uses, go to Settings > Usage.

For more information on how to save on data loading, data retention, and querying costs, see Optimize usage.

What happens when you exceed field limits

Axiom restricts the number of datasets and the number of fields in your datasets. The number of datasets and fields you can use is based on your pricing plan and explained in the table above.

If you ingest a new event that would exceed the allowed number of fields in a dataset, Axiom returns an error and rejects the event. The error message indicates that the dataset has exceeded its field limit. To prevent this error, ensure that the number of fields in your events are within the allowed limits.

How to resolve field limit issues

If you encounter field limit errors, use one of the following approaches to reduce the number of fields in your dataset:

1. Vacuum the dataset fields to remove fields that no longer exist in events within your retention period. This rebuilds the schema from current data and can significantly reduce the field count.

2. Trim the dataset to delete events before a specific date, and then vacuum fields. This is useful if you accidentally ingested events with unwanted fields that are still within your retention period.

3. Use map fields to consolidate multiple related fields into a single map field. This is particularly useful for high-cardinality data like OpenTelemetry attributes or feature flags.

4. If you consistently need more fields, consider upgrading your plan.

To check the current number of fields in a dataset, go to Settings > Datasets and views, and find the dataset in the list.

System-wide limits

The following limits are applied to all accounts, irrespective of the pricing plan.

Limits on ingested data

The table below summarizes the limits Axiom applies to each data ingest. These limits are independent of your pricing plan.

	Limit
Maximum field size	1 MB
Maximum events in a batch	10,000
Maximum field name length	200 bytes

If you try to ingest data that exceeds these limits, Axiom does the following:

• Replaces strings that are too long with <invalid string: too long>.
• Replaces binary with <invalid data>.
• Truncates maps and slices that nest deeper than 100 levels and replaces them with nil at the cut-off level.
• Converts the following float values to nil:
  • NaN
  • +Infty
  • -Infty

Special fields

Axiom creates the following two fields automatically for a new dataset:

• _time is the timestamp of the event. If the data you ingest doesn’t have a _time field, Axiom assigns the time of the data ingest to the events. If you ingest data using the Ingest data API endpoint, you can specify the timestamp field with the timestamp-field parameter.
• _sysTime is the time when you ingested the data.

In most cases, use _time to define the timestamp of events. In rare cases, if you experience clock skews on your event-producing systems, _sysTime can be useful.

Reserved field names

Axiom reserves the following field names for internal use:

• _blockInfo
• _cursor
• _rowID
• _source
• _sysTime

Don’t ingest data that contains these fields names. If you try to ingest a field with a reserved name, Axiom renames the ingested field to _user_FIELDNAME. For example, if you try to ingest the field _sysTime, Axiom renames it to _user_sysTime.

In general, avoid ingesting field names that start with _.

Requirements for timestamp field

The most important field requirement is about the timestamp.

All events stored in Axiom must have a _time timestamp field. If the data you ingest doesn’t have a _time field, Axiom assigns the time of the data ingest to the events. To specify the timestamp yourself, include a _time field in the ingested data.

If you include the _time field in the ingested data, follow these requirements:

• Timestamps are specified in the _time field.
• The _time field contains timestamps in a valid time format. Axiom accepts many date strings and timestamps without knowing the format in advance, including Unix Epoch, RFC3339, or ISO 8601.
• The _time field is a field with UTF-8 encoding.
• The _time field isn’t used for any other purpose.

Requirements for log level fields

The Stream and Query tabs allow you to easily detect warnings and errors in your logs by highlighting the severity of log entries in different colors. As a prerequisite, specify the log level in the data you send to Axiom.

For Open Telemetry logs, specify the log level in the following fields:

• severity
• severityNumber
• severityText

For AWS Lambda logs, specify the log level in the following fields:

• record.error
• record.level
• record.severity
• type

For logs from other sources, specify the log level in the following fields:

• level
• @level
• severity
• @severity
• status.code

Temporary account-specific limits

If you send a large amount of data in a short amount of time and with a high frequency of API requests, Axiom may temporarily restrict or disable your ability to send data to Axiom. This is to prevent abuse of the platform and to guarantee consistent and high-quality service to all customers. In this case, Axiom kindly asks you to reconsider your approach to data collection. For example, to reduce the total number of API requests, try sending your data in larger batches. This adjustment both streamlines Axiom operations and improves the efficiency of your data ingest. If you often experience these temporary restrictions and have a good reason for changing these limits, please contact Support.