Find EC2 Reserved Instances About to Expire

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "ReadReservedInstances",
      "Effect": "Allow",
      "Action": [
        "ec2:DescribeRegions",
        "ec2:DescribeReservedInstances"
      ],
      "Resource": "*"
    }
  ]
}

// expiring-reserved-instances.ts
// Lists active EC2 Reserved Instances in every enabled region that expire within
// the next N days (default 30), soonest first. Read-only.
import {
  EC2Client,
  DescribeRegionsCommand,
  DescribeReservedInstancesCommand,
} from "@aws-sdk/client-ec2";

const args = process.argv.slice(2);
const daysArg = args.indexOf("--days");
const WINDOW_DAYS = daysArg !== -1 ? Number(args[daysArg + 1]) : 30;
if (!Number.isFinite(WINDOW_DAYS) || WINDOW_DAYS < 1) throw new Error("--days must be a positive number");
const AS_JSON = args.includes("--json");
const HOME_REGION = process.env.AWS_REGION ?? "us-east-1";
const DAY_MS = 24 * 60 * 60 * 1000;

type Row = {
  region: string;
  id: string;
  type: string;
  count: number;
  scope: string;
  offering: string;
  platform: string;
  ends: string;
  daysLeft: number;
};

async function enabledRegions(): Promise<string[]> {
  const ec2 = new EC2Client({ region: HOME_REGION });
  const { Regions = [] } = await ec2.send(new DescribeRegionsCommand({}));
  return Regions.map((r) => r.RegionName).filter((r): r is string => !!r);
}

async function expiringIn(region: string, now: Date, limit: Date): Promise<Row[]> {
  const ec2 = new EC2Client({ region });
  // DescribeReservedInstances isn't paginated: one call returns every RI in the region.
  const { ReservedInstances = [] } = await ec2.send(
    new DescribeReservedInstancesCommand({ Filters: [{ Name: "state", Values: ["active"] }] }),
  );
  return ReservedInstances.filter((ri) => ri.End && ri.End <= limit).map((ri) => ({
    region,
    id: ri.ReservedInstancesId ?? "-",
    type: ri.InstanceType ?? "-",
    count: ri.InstanceCount ?? 0,
    scope: ri.Scope === "Availability Zone" ? (ri.AvailabilityZone ?? "zonal") : "Region",
    offering: `${ri.OfferingClass ?? "?"} / ${ri.OfferingType ?? "?"}`,
    platform: ri.ProductDescription ?? "-",
    ends: ri.End!.toISOString().slice(0, 10),
    daysLeft: Math.ceil((ri.End!.getTime() - now.getTime()) / DAY_MS),
  }));
}

async function main(): Promise<void> {
  const now = new Date();
  const limit = new Date(now.getTime() + WINDOW_DAYS * DAY_MS);
  const regions = await enabledRegions();

  const results = await Promise.allSettled(regions.map((r) => expiringIn(r, now, limit)));
  const rows: Row[] = [];
  results.forEach((result, i) => {
    if (result.status === "fulfilled") rows.push(...result.value);
    else console.error(`${regions[i]}: ${(result.reason as Error).name ?? result.reason}`);
  });
  rows.sort((a, b) => a.daysLeft - b.daysLeft);

  if (AS_JSON) {
    console.log(JSON.stringify(rows, null, 2));
    return;
  }
  if (rows.length === 0) {
    console.log(`No active Reserved Instances expire in the next ${WINDOW_DAYS} days (${regions.length} regions checked).`);
    return;
  }
  console.table(rows);
  const instances = rows.reduce((sum, r) => sum + r.count, 0);
  console.log(`${rows.length} reservation(s) covering ${instances} instance(s) expire within ${WINDOW_DAYS} days.`);
}

main().catch((err) => {
  console.error(err);
  process.exit(1);
});

npm install @aws-sdk/client-ec2
npm install --save-dev tsx typescript

# Reservations ending in the next 30 days, all enabled regions
AWS_PROFILE=readonly npx tsx expiring-reserved-instances.ts

# A 90-day window, as JSON
AWS_PROFILE=readonly npx tsx expiring-reserved-instances.ts --days 90 --json

┌─────────┬─────────────┬────────────────────────────────────────┬───────────────┬───────┬──────────────┬─────────────────────────────────┬──────────────┬──────────────┬──────────┐
│ (index) │ region      │ id                                     │ type          │ count │ scope        │ offering                        │ platform     │ ends         │ daysLeft │
├─────────┼─────────────┼────────────────────────────────────────┼───────────────┼───────┼──────────────┼─────────────────────────────────┼──────────────┼──────────────┼──────────┤
│ 0       │ 'us-east-1' │ '4b2f1c9e-8a7d-4e21-b3c5-0d9f6a1e2b7c' │ 'm6i.large'   │ 4     │ 'Region'     │ 'standard / No Upfront'         │ 'Linux/UNIX' │ '2026-10-04' │ 7        │
│ 1       │ 'eu-west-1' │ 'a91c3e57-2f4b-4d8a-9e1c-6b7d5f3a2c10' │ 'r6g.xlarge'  │ 2     │ 'Region'     │ 'convertible / Partial Upfront' │ 'Linux/UNIX' │ '2026-10-15' │ 18       │
│ 2       │ 'us-west-2' │ '0e7d6c5b-4a39-4821-9f0e-1d2c3b4a5f6e' │ 'c6i.2xlarge' │ 1     │ 'us-west-2a' │ 'standard / All Upfront'        │ 'Windows'    │ '2026-10-24' │ 27       │
└─────────┴─────────────┴────────────────────────────────────────┴───────────────┴───────┴──────────────┴─────────────────────────────────┴──────────────┴──────────────┴──────────┘
3 reservation(s) covering 7 instance(s) expire within 30 days.