AWS Cost Optimisation and FinOps Implementation for a Series B SaaS Startup

Key Results

  • 58% AWS Cost Reduction
  • $340k Annual Saving
  • 90-Day Turnaround
  • Real-Time Cost Visibility

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Project Background

A Series B SaaS startup with 18 months of runway was spending $588,000 per year on AWS — 34% of their total operating expenditure. Despite the engineering team’s best efforts, the bill grew 8% every month. The CTO flagged it to the board as a burn-rate risk. They had no visibility into which teams or services were driving costs, and no process to challenge new infrastructure spend before it was provisioned.

The Challenge

We were engaged to cut the AWS bill materially within 90 days — a hard deadline tied to a board update — while not disrupting a product engineering team in the middle of a major feature release. Savings also had to be durable: quick wins like stopping development instances overnight weren’t enough if they reverted the moment we left.

What We Delivered

  • Ran a full spend analysis across all AWS accounts using AWS Cost Explorer, Cost and Usage Reports, and Infracost — surfacing the top 20 cost drivers within 48 hours
  • Rightsized 140 EC2 instances and RDS clusters based on 90-day CloudWatch utilisation data, saving $9,200/month immediately with zero application changes
  • Replaced on-demand EC2 for stateless workloads with Spot Instances via Auto Scaling mixed instance policies, cutting compute costs by a further 62%
  • Purchased a 1-year Compute Savings Plan and targeted Reserved Instances for steady-state RDS, locking in a 35% discount on baseline spend
  • Implemented S3 Intelligent-Tiering and lifecycle policies across 47 TB of object storage, reducing S3 costs by 71%
  • Deployed a tagging enforcement policy via AWS Config and Service Control Policies so every new resource is tagged with team, product, and environment — enabling real-time per-team cost dashboards in Grafana
  • Ran monthly FinOps review meetings with engineering leads for two quarters to embed the cost-awareness culture

Technical Stack

Cost Analysis: AWS Cost Explorer · CUR + Athena · Infracost · Compute: EC2 Spot + Savings Plans · Storage: S3 Intelligent-Tiering · Governance: AWS Config · Service Control Policies · Dashboards: Grafana + CloudWatch

Outcomes

The monthly AWS bill dropped from $49,000 to $20,600 within 90 days — a 58% reduction saving $340,000 annually. The startup presented this at their board meeting and used the improved unit economics as a key data point in their Series C deck. The engineering team now runs a monthly FinOps review independently and has maintained costs within 5% of target for the past two quarters.