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Understand your costs

Updated October 19, 2026Plans: Free, Pro, Enterprise

Overview

ArchFoundry shows two kinds of figure, and always says which one it is. A projection is the AWS on-demand list price for what is drawn, from ArchFoundry's price book. A bill is what AWS actually charged, read from Cost Explorer through your connected account. Archie can also look at every stack ArchFoundry runs and tell you which ones nobody is using. That answer comes from your account's metrics and the price book, not from an AI model.

Prerequisites

  • For projections, nothing beyond a diagram.
  • For billed figures and idle stacks, a connected AWS account. See Connect your AWS account.

Steps

  1. On the canvas, read the price in the top bar. Estimate means a projection at list prices. It becomes a billed figure once the stack has run in a connected account.
  2. Click a card and open the Node tab to see that card's cost.
  3. To change the period the figures cover, click the cost window in the top bar and choose 14 days or 30 days. Fourteen days keeps per-resource figures where AWS provides them. Thirty days shows service totals only, because Cost Explorer keeps no per-resource data that far back.
  4. In the workspace sidebar, click Cost. What you were billed lists each connected account's spend this month so far and last month. Projected for what is drawn but not deployed breaks your drawings down By category, By architecture and Where it runs.
  5. To find waste, ask Archie on the canvas, for example "cut my AWS bill". Archie checks each stack's load balancer requests and database connections for the last seven days.
  6. Under the reply, click Review removing followed by the stack's name and saving. It opens that stack's ordinary Destroy, which lists what it deletes before anything happens.

Example

Ask Archie:

text
Archie, cut my AWS bill.

When two stacks have had no traffic, the reply reads:

text
2 stacks look unused. Removing them would save about $89.02/mo at AWS list prices.
- checkout-staging ($54.51/mo): 0 requests through its load balancer, 0 database connections in 7 days.
- demo-uploads ($34.51/mo): 0 requests through its load balancer in 7 days.
Review removing one below: Destroy shows exactly what it deletes before anything happens.

Archie also names databases bigger than their work, with the next size down and what it saves. Change the card's size on that diagram and deploy it. AWS makes the change during that deploy, with a short restart.

Verify it worked

  • Billed figures in Cost say when they were read from Cost Explorer.
  • After you destroy an idle stack, the total at the top of Deployments drops by its monthly cost.

Troubleshooting

No measured spend yet. No account is connected. Billed figures need a connected account. Projections still work.

Figures look stale. Cost Explorer is read at most once an hour, because AWS charges $0.01 for each read.

Prices look low for your region. The price book is us-east-1 list prices. Other regions usually cost more.

Archie could not judge a stack. A stack with nothing to measure, one too new to judge, or one whose reads failed is called unknown, never idle. Archie will not suggest removing it on a guess.

ArchFoundry is not running anything in your account, so there is nothing of ours to cut. Archie only judges stacks ArchFoundry deployed.

Next steps