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CostWarden

AWS costs · under control

Catch unexpected spend. Before the invoice.

Clear alerts about what changed and recommendations to reduce your spend. In the channels your team already uses.

Connect AWS in 5 minutes See how it works

14 days free · no card · read-only access.

Illustrative example · the same daily overspend

$452One day of excess spend
$9,494After 21 days without action
ObserveDeviateDetectAlert

Example data, run through the same arithmetic the product uses. The shaded band is the normal range for that weekday.

The problem

Thousands of data points. One clear signal.

Spend becomes a pattern by service and day. When it breaks that pattern, you know where to look.

30-day example · amber: excess spend · green: estimated opportunity

The problem

Continue to how it works

Nothing breaks. The bill just gets bigger, quietly, for three weeks.

A memory leak that auto-scales. A viral file on S3. A dev environment nobody turned off in March. None of it pages anyone, because none of it is an outage — it is just money, and money has no alarm.

185,077 points, ten for every dollar of the month.

Averages hide the shape

A fleet that scales with traffic costs less on a Sunday than a Tuesday. A single monthly threshold either fires every weekend or never fires at all — which is why the baseline here is per weekday, per service.

29%of IaaS and PaaS spend is wasted, according to the teams paying for it.

Self-reported estimates from 753 cloud decision-makers, not a measurement anyone took. It is also the default assumption in the calculator below, which is the only reason it is on this page.

Flexera · 2026 State of the Cloud Report

EC2 — Compute is 50% of it.

The invoice is the monitoring

One day of the leak in the example above is $452.10. By the time the bill arrives, $9,494 of it has already been spent.

$4,107 of those dollars sit above the same-weekday normal.

Nobody’s job is the bill

At seed stage there is no FinOps hire — there is one engineer who opens Cost Explorer when something feels off. Watching a dashboard is not a control; it is a hope that someone looks on the right day.

The alert fires on day one: $452 instead of $4,107.

  • 30 days, by serviceTen points = one dollar
  • EC2 — Compute$9,32450%
  • RDS$4,36924%
  • S3$2,12311%
  • Data Transfer$1,89610%
  • CloudWatch$7954%

How it works

Connect. Watch. Act.

Connect your AWS

Create a read-only IAM role and paste its ARN. No access keys or agents.

Learn your normal spend

We analyze 90 days by service and weekday to separate a spike from your usual pattern.

Get an actionable alert

One message with the service and excess spend. Daily scans use settled AWS data, which can lag 24–48 hours.

Setup guide

The deliverable

From a change in spend to your next action.

An alert to investigate. A recommendation to optimize. Together in one place.

The spike, with context

Amazon Elastic Compute Cloud - Compute · demonstration data

+$452 (+251%)

Typical spend for this weekday is $180.30.

SlackMicrosoft TeamsGoogle ChatPagerDuty

Settled AWS data, with a 24–48 hour lag. Alerts are not real-time.

Rightsizing opportunities

$312/mo estimated

  • i-0a91c4e2f7b3d8051m6i.2xlarge → m6i.xlarge−$138
  • i-04f7b2a9c1e6d3327r6i.xlarge → r6i.large−$94
  • vol-0c72e19b4a5f8d6e3gp2 · unattached 41 days → delete−$46
  • i-0d38e5c7a92b1f460c6i.4xlarge → c6i.2xlarge−$34

Two different things, deliberately side by side. The anomaly is “something changed today”. The rightsizing list is “this has been wasteful all along” — it comes from AWS Compute Optimizer, and it never pages anyone.

See detection and its limits

Access

Visibility into costs. Control stays with you.

You create and can revoke the IAM role. CostWarden reads costs and recommendations; it cannot modify your resources.

Read-onlyNo AWS keysNo agents
The full access page
See the 5 read permissions

  • ce:GetCostAndUsage

    Daily cost by service and by linked account — the numbers on your bill, nothing about what produced them.

  • compute-optimizer:GetEC2InstanceRecommendations

    AWS’s own view of which instances are oversized, and what it would resize them to.

  • compute-optimizer:GetEBSVolumeRecommendations

    The same for volumes, including the ones nobody has attached to anything in weeks.

  • ec2:DescribeInstances

    The type, size and state of your instances — their shape, never anything running inside them. Compute Optimizer will not answer about instances the caller cannot list, so without this the recommendation above does not arrive at all.

  • ec2:DescribeVolumes

    The same shape for volumes: type, size, and what each is attached to. Never a byte of what is stored on them.

  • Plus sts:AssumeRole from our side into that role, proving your organisation’s external ID on every call. Revoke the role and the connection is over the same second.
What it cannot do
  • Install an agent, a sidecar or anything else in your account.
  • Write, modify, stop or delete a single resource — the role has no write permission at all.
  • Read your data, logs, buckets, databases or environment variables.
  • Reach your account without the external ID issued to your organisation.

Price

A clear price. A fixed ceiling.

From $39 a month. Above $25,000 of AWS spend the price stops at $179 and stays there — a cost tool should not charge you most in the month you most need it.

Calculate whether it pays off

Starts at 29%, what cloud teams estimate for their own IaaS and PaaS spend — Flexera, 2026 State of the Cloud Report. Drag it to whatever you actually believe.

Estimated waste, per month
$2,320
Estimated waste, per year
$27,840
CostWarden Team, per year
$948

At this bill you would be on Team — $79/month, the band for AWS spend up to $25,000 a month.

Share of that waste CostWarden costs

3.4%

Recover that much of it and the subscription has paid for itself. CostWarden does not remove waste — it reports the day a service breaks from its normal and shows which resources Compute Optimizer calls over-provisioned. Acting on it stays your call.

Arithmetic you control: bill × share, then × 12. No industry average is applied to your figures except the one shown above, which you can change.

The bands

Starterup to $5,000/mo$39/mo
Teamup to $25,000/morecommended$79/mo
Scaleabove $25,000/mo$179/mo

Your band is a number you can read before you sign up. It does not move when your bill moves inside it, and there is no metered component to model.

What every plan includes
  • All four delivery channels, as many as you want
  • Unlimited team members
  • The same detection and the same rightsizing on every band
  • Ninety days of backfill on connection, kept rolling
  • A price ceiling: above $25,000 of spend, $179 is the most you pay
Start the 14-day trialFull pricing and comparison

14 days from your first working AWS connection. No card until you decide.

Before you ask

Your questions, answered.

The essentials before connecting your account.

The longer answers
Why use this if AWS already has alerts?

AWS already supports cost anomaly alerts in Slack. CostWarden brings its documented weekday baseline, rightsizing recommendations and four channel integrations into one self-serve setup. If your existing AWS setup meets your needs, there is no reason to pay $79 for another tool.

How noisy is it?

One message when an episode starts, and after that only if it escalates — never one a day. A leak running for nine days is one open episode with a running total attached to each message, not nine alerts, and no single scan can send more than 5. That is the difference between a tool you keep and a channel you mute.

What happens after the trial?

14 days from your first working AWS connection. If you do not subscribe, ingestion pauses and your baseline stays put; nothing is deleted for six months, and nothing is charged without you choosing a plan.

Our bill is small. Is this worth it?

Do the arithmetic above rather than trusting this answer. At the cited 29% waste assumption, a year of Starter is covered by anything above about $135 a month of AWS spend — so on that assumption almost any real bill clears it. The honest version of the question is how much waste you believe you have: drag that slider down to 5% and the panel starts telling you no below roughly $800 a month, which is where AWS’s free anomaly alerts and a calendar reminder are the better answer.

Do you support GCP or Azure?

No, and there is no plan to. Cost semantics do not transfer between providers, and a shallow second integration would make the AWS one worse.

Can it fix the problem for me?

No. The role is read-only and will stay read-only — a tool with permission to terminate your instances is a much bigger thing to trust than a tool that tells you which one to look at.

Find out tomorrow morning, not on the invoice.

Connect a read-only role and the next scan tells you whether your spend has broken from its normal — including, quite possibly, that it has not.

Connect AWS in 5 minutes

Read-only. No agents. 14 days, no card.

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