Cost as Code by MoreThanOps

Glossary

The words used across this site, each with a short definition.

Last reviewed

Index cards flip over one after another, each showing a term (Savings as Code, savings ledger, spend rule, quality bar) and settling into a neat alphabetical stack.
Every term on this site, in one place.

In 30 seconds

Each term below has a short definition and, where it helps, a link to the page that explains it. Terms are grouped by what they are about, not in alphabetical order.

The method

How the terms fit together: one method, two parts, and the objects each part produces.

Cost as Code

Managing cloud and AI spend with the habits of software teams: every saving is a reviewed change, every spend rule lives in a versioned file, and every result is measured on the bill. See what it is and the principles.

Savings as Code

The method of Cost as Code for cutting spend. Every saving reaches the owning team as a pull request with its estimate and rollback, the team approves it, and the saving is measured on the bill after the merge. See Savings as Code.

Spend as Code

The method of Cost as Code for keeping spend in line: budgets, allowed instance families, allowed models and token limits in one versioned file, checked in review, in the cloud account and in the AI gateway. Coming soon. See Spend as Code.

Savings as Code for AI

Savings as Code applied to model and token spend: a smaller model on a route, prompt caching, batch processing, output limits, each as a reviewed change measured on the bill. It starts with model right-sizing. See Savings as Code for AI.

Model right-sizing

Choosing, for each task, the smallest or cheapest model that meets a measured quality bar, and checking that choice again as models and prices change. It sits inside Savings as Code. See Savings as Code for AI.

Right-modeling

Our short name for model right-sizing: rightsizing for AI.

Find, Fix, Prove, Prevent

The lifecycle of a saving: find the waste with an estimate, fix it with a change the owner approves, prove it on the bill, and prevent it from coming back with a spend rule. See the lifecycle.

FinOps

The practice of managing the business value and cost of cloud and technology, with engineering, finance and business teams working together. The FinOps Foundation™ publishes its own definition on What is FinOps? (checked November 8, 2026). Cost as Code is one way to do the implementing work.

FinOps as Code

A related term used in several ways: by some for configuring cost tools in code, by others for keeping cost governance rules, budgets and policies in version-controlled files. Cost as Code overlaps with both and adds a precise unit (one reviewed change) and test (the bill). See why "as code".

Infrastructure as code

Defining infrastructure "through source code that can then be treated just like any software system" (martinfowler.com, checked November 8, 2026).

Policy as code

Rules written in files and checked by a tool, rather than written in a document (Open Policy Agent, checked November 8, 2026).

GitOps

Running operations from Git, with changes made by pull request and systems kept to match the repository (OpenGitOps, checked November 8, 2026).

Changes

Pull request

A proposed change to a repository that shows the exact change, its author and reason, and is reviewed before it is merged. GitHub calls them "proposals to merge code changes into a project" (GitHub Docs, checked November 8, 2026).

Saving

A change that lowers what a cloud or AI service costs for the same work, such as a smaller instance, a deleted volume or a smaller model on a route.

Estimate

The expected effect of a saving a month, stated before the change is made.

Measured saving

The effect of a saving as it shows on the bill, compared with the baseline, about 30 days after the merge.

Savings ledger

A record with one line per merged saving: its estimate, its measured saving and a link to the change. Finance can audit it line by line.

Rollback

The way to undo a change, written in the pull request before it is approved.

Baseline

The month of spend a saving is measured against.

Change-log repository

A small repository where console changes are described and approved as pull requests, for teams without infrastructure as code.

Money

Showback

Showing each team or product the cost it owns, for visibility, without moving the money (AWS, checked November 8, 2026).

Chargeback

Recording each cost against the team or product that owns it in the general ledger (same source).

Unit cost

What one unit of business costs, such as one order, one ride or one AI request (FinOps Foundation, checked November 8, 2026).

Commitment

A discount bought in exchange for steady usage over one or three years, such as a Savings Plan or a reservation.

Budget

A spending limit for an account, team or service over a period, with alerts when costs approach or pass it (AWS, checked November 8, 2026).

Rules

Spend rule

A rule about what may be spent and on what, such as a budget, an allowed instance family or an allowed model per route, kept in a versioned file.

Check in review

A test that runs on a pull request and fails, with the reason, when the change would break a spend rule.

AI

Route

One place where an application calls an AI model for one task, such as a support summary or a contract check.

Quality bar

A set of real requests for a route with the answers you would accept, used to decide which model is good enough.

Prompt caching

Billing a repeated prompt prefix at a lower rate when it is reused within the provider's cache lifetime.

Batch processing

Sending AI requests that can wait as a batch, at a lower price than requests that need an answer now.

Data

FOCUS

The FinOps Open Cost and Usage Specification (FOCUS™), "an open specification that normalizes billing datasets" (FOCUS, checked November 8, 2026).