EC2 Rightsizing
Infralyst analyzes CloudWatch data across your EC2 fleet and surfaces savings opportunities. When you're ready, generate ready to merge Terraform PRs from Slack or the dashboard.
- Unlimited free recommendations
- Read-only IAM role
- Your team reviews and merges every change
| Resource | CPU | Memory | Current | Recommended | Savings | |
|---|---|---|---|---|---|---|
| api-prod-01us-east-1 · 72 days | 18%avg 4.2% | 24%avg 11% | m5.2xlarge | m5.xlarge | $47/mo | Generate PR |
| worker-batch-02us-east-1 · 52 days | 22%avg 8.1% | 28%avg 12% | c5.xlarge | c5.large | $23/mo | Generate PR |
| cache-redis-03us-east-1 · 45 days | 19%avg 6.8% | 21%avg 9% | r5.large | r5.medium | $18/mo | Generate PR |
You're paying for
EC2 capacity you don't use
Teams pick an EC2 instance type for peak load and move on. Utilization drops, workloads change, but the bill doesn't. Most engineers know this, but actually fixing it means auditing instances across every region, picking the right target type, updating the Terraform, and convincing your team nothing will break. So it never happens.
AWS tools like Cost Explorer and Compute Optimizer will flag the waste. But they stop at a recommendation. Infralyst picks up where they leave off: it analyzes your CloudWatch data, selects a conservative target, and generates a PR your team can review and merge.
How the analysis works
A conservative, multi gate approach. If any check fails, it doesn't get recommended.
1. Collect utilization metrics
Infralyst pulls CPU and memory utilization from CloudWatch for each EC2 instance, using up to 365 days of historical data.
2. Run the analysis gates
Each instance passes through data quality validation, utilization thresholds, and seasonality checks. An instance only gets a recommendation if all gates pass.
3. Generate the recommendation
Infralyst recommends the next size down in the same instance family. When you're ready, an AI agent reads your Terraform, writes the change, and validates it. The analysis is fully deterministic.
Thresholds & methodology
Every gate and threshold Infralyst checks before recommending rightsizing. These are intentionally conservative. We'd rather miss a savings opportunity than recommend a change that causes problems.
Pre-flight
Data quality
CPU & Memory
Seasonality
For instances with 60–365 days of data, P95 is checked per weekly bucket. If any week exceeds the 40% threshold, the instance is excluded.
Infralyst only recommends stepping down one size at a time. If there's room to go further, it happens across multiple analysis cycles.
What the PR looks like
Infralyst opens a Terraform pull request in your repo. Your team reviews and merges it like any other change.
Downsize EC2 instance worker-batch-02: c5.xlarge → c5.large (-$23/mo)
EC2 instance worker-batch-02 in us-east-1 can be downsized from c5.xlarge to c5.large, saving an estimated $23/mo.
| Metric | Avg | P99.5 |
|---|---|---|
| CPU | 8.1% | 22% |
| Memory | 12% | 28% |
Lookback: 52 days
Trigger PRs directly from Slack
Get notified when new savings are found. Review the details and generate a PR without leaving Slack.
New EC2 savings recommendation · Save $23.00/mo
Resource
worker-batch-02 (us-east-1)
Lookback
52d
CPU Avg
8.1%
CPU P99.5
22%
Mem Avg
12%
Mem P99.5
28%
Current
c5.xlargeRecommended
c5.largeView on Infralyst
Safety & guardrails
Built for production infrastructure. Here's what Infralyst won't do.
Conservative thresholds
Infralyst won't recommend rightsizing unless CPU and memory P99.5 (or P95 for longer windows) are comfortably below 40%. A single spike won't trigger a false recommendation.
Seasonality-aware
For instances with 60+ days of data, P95 utilization is checked per weekly bucket over the full observation window. If any week exceeds 40%, the instance is excluded. No recommendation, no risk.
Downtime warnings
Changing an EC2 instance type requires a stop and start. Every PR includes a prominent warning so your team can plan a maintenance window.
PR-only changes
Infralyst never applies changes directly. Every recommendation is delivered as a notification in Slack or in our console. You trigger PR generation, review, test, and merge on your timeline.
Also available for Auto Scaling Groups, ECS Fargate, and EBS Volumes.
EC2 Rightsizing FAQ
Learn more about EC2 optimization
How to Rightsize EC2 Auto Scaling Groups
Rightsizing an ASG means every instance in the group is smaller and cheaper. Here's how to evaluate whether your group can safely go down a size.
March 31, 2026
How to Enable EC2 Memory Metrics in CloudWatch
A simple guide to getting RAM usage data into CloudWatch so you can actually perform EC2 rightsizing without flying blind.
March 27, 2026
Best Practices for EC2 Rightsizing
A practical guide to EC2 rightsizing within the same instance family: how much data you need, what thresholds to set, and the guardrails that keep you safe.
December 19, 2025Want more? View all articles
Start rightsizing your EC2 instances
Connect your AWS account and Infralyst will find instances worth rightsizing. When you're ready, generate the Terraform PR in one click.
- No credit card required
- Read-only IAM role
- Your team reviews and merges every change