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Cost anomalies notify teams of unexpected daily cost spikes so engineers can fix misconfigurations or runaway workloads before they become expensive. When anomaly detection is enabled for a Cost Report, Vantage detects anomalies and lets you send alerts via email, Slack, Microsoft Teams, or Jira.
For users on a team with an Access Policy assigned, the Anomalies tab lists only anomalies in the costs their policy allows. Vantage runs detection separately on that scoped data, so these users can see different anomalies than an unrestricted user sees on the same report. Archiving or ignoring an anomaly changes it only for people with the same combination of policies.If a Cost Report has an anomaly notification enabled, Vantage sends it for anomalies detected under each Access Policy on the account. When that notification is an email to an address that belongs to a Vantage user, Vantage skips the email if the anomaly is not for an Access Policy that user has. For all other notifications, Vantage sends the anomaly notification.
Anomaly Detection is one of several ways Vantage notifies you about cost changes. For a side-by-side comparison with Cost Alerts, Report Notifications, Budget Alerts, and the FinOps Agent, see Anomaly Detection vs. Other Alert Types.

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Enable or Disable Anomaly Detection

Anomaly detection is on for a Cost Report unless you turn it off. Anyone who can view the report can open Manage Forecasts & Anomalies. Edit access is required to save a change.
  1. Open the Cost Report, click the ellipses (…), then select Manage Forecasts & Anomalies.
  2. Set Anomaly Detection to On or Off.
  3. Click Save.
Reports without their own setting follow the workspace default, which Organization Owners can change. To return a report to the workspace default, click the selected On or Off option again to clear it, then click Save. For accounts using Access Policies, turning Anomaly Detection off stops the extra anomaly runs those policies require and reduces the Build Hours they consume.

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How Anomaly Detection Works

Anomaly detection runs on each Cost Report where it is enabled. For each report, Vantage:
  1. Groups the report’s filtered cost data into time series by provider, service, and cost category (for example, AWS > Amazon EC2 > Data Transfer or Azure > Virtual Machines > Compute).
  2. Trains a machine learning forecast on each series using up to the most recent 6 months of daily cost data for that report. (Newer accounts train on whatever history is available. Each series needs more than 12 days of data before it can be evaluated.)
  3. Flags days where the actual cost exceeds the forecast’s upper bound as candidate anomalies.
  4. Applies noise filters to remove tiny or expected fluctuations (see Noise Filters Applied to Candidates).
  5. Records each surviving anomaly on the Cost Report and, when configured, sends an external notification the first time the anomaly’s trend exceeds your Alert Threshold.
See What Counts as an Anomaly for the exclusion and noise-filter rules.
To get started with cost anomaly detection and alerts, you can also view a video demo on Vantage University .

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What Counts as an Anomaly

Two things determine whether a daily cost spike becomes a recorded anomaly: whether the underlying line item is in scope for detection at all, and whether the candidate survives Vantage’s noise filters. Both rules are intentional and uniform across all accounts to keep the anomalies list actionable rather than noisy.

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Excluded from Detection

To keep the model focused on usage signals, Vantage excludes a few categories of line items from detection entirely: Detection uses the same cost amount the report displays, with the excluded fee types above removed. Discounts, credits, refunds, tax, and amortization all follow the report’s settings.

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Noise Filters Applied to Candidates

After the model identifies a candidate anomaly (a day where cost exceeds the forecast’s upper bound), Vantage applies several noise filters before recording it:
These filters mean that the same underlying cost spike can surface as an anomaly on a narrower Cost Report and be suppressed on a broader one. See the FAQ for examples.

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Anomaly Detection vs. Other Alert Types

Vantage offers several ways to notify you about cost changes. Choose based on whether you want unsupervised outlier detection, fixed thresholds, or scheduled summaries. For a complete delivery matrix (which alert types support which channels), see Alert Notifications below.

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View Cost Anomalies

To view cost anomalies for a Cost Report, navigate to that report and select the Anomalies tab on the top left of the report.
A Cost Report with the Anomalies tab open, listing detected anomalies.
Anomalies are considered Active for the first 7 days after they occur. Once that window passes, they automatically move to an Archived state. Historical anomalies remain visible in the Cost Report. The Anomaly Detected column shows the date the cost anomaly occurred. Alerts are sent only the first time a given anomaly is detected. If the same (provider, service, cost category) series remains elevated for several days, you will not receive duplicate alerts in that window.

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Take Action on an Anomaly

1
From the Anomalies tab, click the link in the Category column to open the anomaly in its Cost Report.
2
The bar for the anomalous day is visually highlighted. Hover over it to view details. If Vantage identified a single resource as the likely cause, the resource is shown alongside the anomaly category (for example, Compute for production-cluster). When the Cost Report is grouped so that the attributed resource appears as a row, that row is also marked. In the top right of the report header, click Manage Anomaly.
3
Select one of the following actions:
  • Create an Issue: Open a new issue pre-populated with a link back to this Cost Report and anomaly. Assign it to yourself or a teammate.
  • Mark as Archived: Move the anomaly out of the Active list.
  • Ignore: Remove the anomaly from the list entirely. You can provide optional feedback about why you ignored it.
Creating an issue from a cost anomaly on a Cost Report.
Ignoring, archiving, or creating an issue for an anomaly does not train, tune, or suppress the detection model. The model has no feedback loop from these actions. Detection always re-runs on the report’s filtered cost data within the last 6 months, with the excluded charge types and categories listed above removed.

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Resource Attribution

Vantage attempts to identify the resource responsible for an anomaly. When one is identified, the resource is appended to the anomaly’s category (for example, Compute for production-cluster) and, if the Cost Report is grouped so that the resource appears as a row, that row is also marked. Attribution is best-effort:
  • Vantage attributes at most one resource per anomaly. The resource is selected when a single resource accounts for more than 50% of the cost change in the affected (provider, service, cost category) series.
  • When no single resource exceeds the 50% threshold, no resource is attributed. The anomaly may instead be caused by multiple resources, by a category without resource-level granularity, or by a provider that does not expose per-resource identifiers.
  • When a resource is attributed, it is a directional starting point for investigation rather than a definitive root cause. Inspect groupings and drilldowns on the Cost Report to confirm.

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Configure Cost Anomaly Alerts

Anomaly alerts can be delivered to email, Slack, Microsoft Teams, and Jira. To use Slack, Teams, or Jira, first configure the Slack, Microsoft Teams, or Jira integration. (Slack and Microsoft Teams are mutually exclusive: you can connect one or the other, not both.)
To receive alerts for any detected cost anomalies on a Cost Report:
1
From the top of the Anomalies tab on a Cost Report, click Configure Alert.
2
Select email recipients from your Vantage users.
3
Enter an Alert Threshold (dollar amount). See Understanding the Alert Threshold below.
4
(Optional) If you have Slack, Microsoft Teams, or Jira configured, select channels or a Jira project in the corresponding fields.
5
Click Save.
To change recipients or the threshold, click Configure Alert again and update the settings.
At this time, you cannot configure an anomaly alert for a specific resource. To monitor a particular workload, create a Cost Report filtered to its tag, account, region, or service and configure an alert on that report.

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Understanding the Alert Threshold

The Alert Threshold is a notification threshold, not a detection sensitivity. It does not change which anomalies Vantage detects. It only controls which detected anomalies are sent externally. Vantage compares the threshold against an anomaly’s trend value, where:
If trend >= threshold, the alert is delivered to the configured recipients. Anomalies below the threshold are still recorded on the Anomalies tab. They just don’t fire an external notification.
Two threshold behaviors to be aware of:
  • A blank Alert Threshold has no filtering effect. If you leave the field empty when you configure an alert, Vantage sends a notification for every detected anomaly with a positive trend, which can result in a high volume of alerts on a busy Cost Report. Enter a dollar amount that represents a deviation worth acting on.
  • Lowering the threshold afterward does not backfill notifications. The threshold is evaluated when an anomaly is first processed for alerting. Anomalies that were already evaluated and skipped will not be sent if you later lower the threshold. Only newly detected anomalies are compared against the updated value.

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Alert Notifications

When an anomaly fires above your Alert Threshold, Vantage sends a single notification per delivery channel. Notifications include the report title, the affected service and cost category, and the trend amount. Notifications also display amounts in your workspace’s configured currency.

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Delivery Channels

Cost Anomaly Alerts support email, Slack, Microsoft Teams, and Jira. The matrix below also covers the other Vantage alert types so you can quickly compare.
Slack and Microsoft Teams are mutually exclusive at the integration level: you can connect either Slack or Microsoft Teams, not both. See the Slack and Microsoft Teams integration docs for setup. Jira delivery requires the Jira integration.

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Detected On vs. Occurred On

Slack notifications surface two dates:
  • Occurred On: the date the costs were accrued in your cloud provider.
  • Detected On: the date Vantage detected the anomaly.
These dates can differ when:
  • The cloud provider released or updated the billing data for Occurred On after the fact. Some providers refine the previous day’s data over the next 24–48 hours.
  • A series only became anomalous once additional history filled in around it. The model evaluates each day in the context of the surrounding days; a spike on day N may not look anomalous until day N+2’s data is available.
If a Slack alert arrives several days after the Occurred On date, that’s almost always one of the two scenarios above rather than a delivery delay.

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Investigate Anomalies with the FinOps Agent

If the FinOps Agent is enabled for your account, anomaly notifications sent to Slack include an Investigate Anomaly button. Clicking it starts a guided investigation: the Agent fetches the anomaly, queries the surrounding daily costs, gathers resource details, and posts a structured summary back in the Slack thread. Vantage Slack notifications also include the report token and anomaly tokens as metadata, so the Agent has full context when responding to follow-up questions in the same thread. See Investigate Cost Anomalies for details.

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Frequently Asked Questions

The default All Resources Cost Report covers your full account spend. The detector’s report-level noise threshold is 0.5% of the report’s total daily cost, which means a service-level spike that is significant on its own can fall below the threshold once it’s compared to your entire daily cloud bill.If you want anomaly coverage for a specific provider, service, tag, account, or team, create a narrower Cost Report scoped to those filters and configure an alert on that report. Each report runs its own detection, so the same spike that’s suppressed on All Resources can surface on a focused report.
A few reasons a narrow Cost Report can fail to flag a spike that looks obvious by eye:
  • The series has limited history in the report’s scope: Each (provider, service, cost category) series needs more than 12 days of data within the report’s 6-month training window to be evaluated.
  • Prior spikes have widened the forecast’s upper bound: If the same series spiked previously, the forecast’s upper bound is wider in response to that volatility, so a new spike of similar size can fall inside the widened range without being flagged. Recurring monthly or quarterly spikes can become “expected” to the model.
  • One of the noise filters suppressed it: Most commonly, the new value is not more than 20% above the trailing 7-day average, the day-over-day change wasn’t positive, or another anomaly was already detected in the previous 7 days.
If you believe a real anomaly is being missed, contact support with the report token and the affected date.
Anomaly Detection is built around daily outliers. If costs ramp up smoothly over weeks or months without any single day standing out, no day on its own is anomalous and the detector does not flag the trend.For gradual ramps and sustained growth, Cost Alerts are the right tool. Cost Alerts let you compare day-over-day, week-over-week, month-over-month, or quarter-over-quarter changes against a percentage or dollar threshold you choose.
The anomaly amount is the net cost change within the Cost Report’s filters. A spike that contributes $3,000 to one report can contribute $8 to another report whose filters exclude most of the underlying costs. Both numbers are correct for their respective scope.If you follow an anomaly link and the amount looks unexpected, check whether you’re viewing it on the report it was detected on or on a different report. Anomalies are scoped to the report that detected them.
Anomaly detection is not perfectly deterministic. Detection runs on its own schedule per Cost Report, and two runs that fall on different days see slightly different cost windows—one extra day at the end and one fewer day at the start—which can shift what each run considers anomalous.For two workspaces with the same integrations, expect minor day-by-day differences in counts. The underlying anomalies surface in both reports over time.
Each anomaly is evaluated in isolation against your Alert Threshold. Vantage does not sum across consecutive days. If a $60 anomaly is detected on day 1 with a $100 threshold, no alert fires. If costs continue to climb on day 2, back-to-back suppression typically prevents a new anomaly from being detected in the same series for 7 days.For threshold-based monitoring of sustained cost growth, use Cost Alerts with a comparison interval (day-over-day, week-over-week, month-over-month, or quarter-over-quarter).
The Alert Threshold is evaluated when an anomaly is first processed for alerting. Once a detected anomaly has been evaluated against the threshold—even if it was below the threshold and no notification was sent—it is marked as processed and will not be re-evaluated.Lowering the threshold only affects anomalies that are newly detected after the change. To monitor sustained cost growth that may have already been detected, use a Cost Alert with a comparison interval instead.
No. The detection model has no feedback loop from these actions. Ignoring or archiving an anomaly only changes what you see on the Anomalies tab; the model will still evaluate the same (provider, service, cost category) series with the same logic the next time detection runs.
A series’s recent variance directly affects how wide the forecast’s expected range is. When the same series has spiked repeatedly at a similar magnitude, the forecast’s upper bound widens to reflect that variability, and a new spike of similar size can fall inside the wider range without being flagged as an outlier.If you want to monitor a recurring increase regardless of whether the model considers it expected, use a Cost Alert with a month-over-month threshold.
Anomaly detection trains on up to the most recent 6 months of the Cost Report’s filtered data, regardless of how much history you have imported. Newer accounts train on whatever is available, and each (provider, service, cost category) series needs more than 12 days of data to be evaluated.
Vantage preserves anomaly history within your account’s cost retention window so older anomalies remain searchable on the Cost Report. Two cleanup rules apply:
  • Recent anomalies that are no longer detected are removed. When detection re-runs, anomalies from roughly the last 3 months that are no longer present in the report’s data (for example, after a backfill correction or filter change) are deleted. Older anomalies are preserved as history.
  • Anomalies past your account’s cost retention window are deleted. Anything outside the retention window is removed during cleanup.

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Troubleshooting

A few common causes:
  • The spike is suppressed by a noise filter: Most commonly, the spike is below $5, below 0.5% of the report’s total daily cost, or not more than 20% above the trailing 7-day average for that series.
  • The series doesn’t have enough history: A series needs more than 12 days of data within the 6-month training window before it is evaluated.
  • The report is broad and the spike is small relative to the total. Create a narrower Cost Report scoped to the affected provider, service, tag, or account, and check the Anomalies tab on that report.
  • The series is already volatile: Past spikes or high variance widen the forecast’s expected range, so a new spike can fall inside the wider range and not register as an outlier.
In Slack, compare the Detected On and Occurred On dates in the notification (see Detected On vs. Occurred On for why they can differ). Microsoft Teams notifications show a single date, so this comparison isn’t available there. In both cases, the delay is most often caused by the underlying provider releasing or updating billing data after the fact, or by a series only becoming anomalous once additional surrounding days were available to evaluate.If you believe the delay is not explained by either case, contact support with the report token, anomaly date, and the date the alert was received.
Vantage attributes at most one resource per anomaly, and only when that resource accounts for more than 50% of the cost change in the affected (provider, service, cost category) series. When multiple resources contribute, or when the cost category contains resources moving in opposite directions, the heuristic can attribute a misleading resource (or none).Treat the attributed resource as a starting point. Use the Cost Report’s groupings and drilldowns (for example, group by resource ID, region, or a tag) to confirm what actually drove the spike.
The alert amount is the anomaly’s trend value: the cost on the anomalous day minus the trailing 7-day average for that series. It is not the day-over-day delta and it is not the total cost for the day. Use it as a measure of how much the day deviated from recent normal, not as the spike’s absolute size.If you want to monitor the day-over-day or week-over-week dollar increase directly, use a Cost Alert instead.