How I Helped a Startup Reduce AWS Costs by 50%

•2.24 min read
FinopsAWSCost OptimizationCase Study

The Challenge

When I first audited CloudWidget Inc.'s AWS infrastructure, they were spending $45,000/month on compute alone. The startup had grown rapidly, but their infrastructure hadn't been optimized since launch. Their bill was growing 15% month-over-month, unsustainable at their burn rate.

The team knew something had to change, but they didn't have a systematic approach to cost optimization. They'd made some ad-hoc improvements, but without a clear strategy, costs kept rising.

The Audit

I spent two weeks analyzing their infrastructure across multiple AWS services:

  • EC2 instances: Over-provisioned instances with single availability zone deployments
  • RDS databases: Multiple unused read replicas consuming costs
  • Data transfer costs: Inefficient data flow between regions
  • Unused resources: Orphaned volumes, snapshots, and unattached elastic IPs

The Approach

Step 1: Rightsizing (40% savings)

The biggest opportunity was EC2 instance sizing. They had many t3.2xlarge instances running at 5-10% CPU utilization. After analysis:

# Analysis showed these instances could be t3.medium
# Savings: $2,400/month
aws ec2 describe-instances --query \
  'Reservations[].Instances[].[InstanceId,InstanceType,Placement.AvailabilityZone]' \
  --output table

We rightsized 80% of their fleet to appropriate instance types without performance impact.

Step 2: Reserved Instances (35% savings)

For the 12 production instances with stable workloads, we purchased 1-year reserved instances:

  • Production compute: $8,500/month → $6,200/month
  • Additional savings from volume discounts

Step 3: Spot Instances (15% savings)

Non-critical batch jobs were migrated to Spot instances:

  • Data processing jobs using Spot Fleet
  • Batch analytics workloads with 90% discount vs On-Demand
  • Saved $2,100/month with minimal reliability impact

Step 4: Database Optimization (10% savings)

  • Consolidated read replicas
  • Migrated to Aurora Serverless for variable workloads
  • Eliminated unused dev/staging databases running 24/7

Results

Monthly savings: $23,400 (52% reduction)

| Category | Before | After | Savings | |----------|--------|-------|---------| | EC2 | $30,000 | $12,600 | $17,400 | | RDS | $8,000 | $6,200 | $1,800 | | Data Transfer | $4,500 | $1,950 | $2,550 | | Other Services | $2,500 | $2,250 | $250 | | Total | $45,000 | $23,000 | $22,000 |

The Quote

"We reduced our bill by 52% in just 3 months, and we actually improved performance. The key was having an expert guide us through the process." — CTO, CloudWidget Inc.

Key Takeaways

  1. Visibility is critical: Most teams don't know where their money is going
  2. Rightsizing is powerful: It's often the lowest-hanging fruit
  3. Reserved instances require planning: Commit carefully but confidently to long-term patterns
  4. Automation prevents regression: Cost optimization is ongoing, not one-time

The best part? Their team learned these practices and maintains the cost discipline independently. That's the goal of every engagement.