## TL;DR
AWS "rate exceeded" means you are calling an API faster than your quota, and the fix is client-side: exponential backoff with jitter, plus batching calls that do not need to be individual. Retrying immediately makes it worse; the throttle lasts longer the harder you hammer it. Find the throttled calls in CloudTrail, add backoff, and check whether a quota increase is actually warranted.

## Error / query
```text
AWS "rate exceeded" API errors: backoff strategy
```

## Use this skill when
- Logs show RateExceeded or ThrottlingException from AWS SDK calls
- A deploy or autoscaling event suddenly starts failing with API errors
- CloudTrail shows a spike in throttled API calls
- You need a backoff pattern to put in code or in a script

## Not for this skill when
- The error is AccessDenied or InvalidParameter; those are not throttling
- You are hitting a hard service limit (like max VPCs); request a limit increase instead
- The throttling is on someone else's API; backoff still helps but you cannot raise their quota

## Steps

### Step 1: Find which API calls are being throttled
```bash
aws cloudtrail lookup-events --lookup-attributes AttributeKey=EventName,AttributeValue=DescribeInstances --max-items 5 2>&1 | head -20
```
Expected: recent events; check your application logs for the exact "Rate exceeded" error text to identify the call.

### Step 2: Check the current throttle rate in your app logs
```bash
journalctl -u myservice --since "1 hour ago" | grep -ci 'rate exceeded\|throttl'
```
Expected: a count; if it is climbing, the retry storm is feeding itself and you need backoff now.

### Step 3: Add exponential backoff with jitter to the retry loop
```bash
printf 'import random, time\ndef aws_call_with_backoff(fn, tries=5):\n    for i in range(tries):\n        try:\n            return fn()\n        except Exception:\n            time.sleep(min(2 ** i + random.uniform(0, 1), 20))\n    return fn()\n' > /tmp/backoff.py && cat /tmp/backoff.py
```
Expected: the helper prints back; sleeps grow 1s, 2s, 4s, 8s plus random jitter, capped at 20s.

### Step 4: Verify the SDK is using the standard retry config
```bash
python3 -c "import botocore.config; c=botocore.config.Config(retries={'max_attempts': 5, 'mode': 'adaptive'}); print(c.retries)"
```
Expected: the adaptive retry config prints; adaptive mode is the one that actually backs off on throttling.

### Step 5: Check whether the quota itself needs raising
```bash
aws service-quotas list-service-quotas --service-code ec2 --query 'Quotas[?contains(QuotaName, `Rate`)].{Name:QuotaName,Value:Value}' --output table 2>&1 | head -15
```
Expected: the API rate quotas; if you are legitimately near the quota with good backoff, file an increase request.

## Variant phrasings

### "ThrottlingException in boto3"
Same fix: adaptive retry mode plus jittered backoff; boto3's default legacy mode retries too aggressively.

### "AWS API rate limits during Terraform apply"
Terraform hammers Describe calls; set parallelism lower and space applies out, or the backoff in the provider does the waiting for you.

### "How to add jitter to retries"
Add a random 0-1 second (or 0-100% of the delay) to every sleep; without jitter, all your clients retry in lockstep and re-throttle each other.

## Why it happens
AWS throttles per API per region to protect the control plane; SDKs retry by default, and naive immediate retries turn one throttle into a sustained storm. Backoff with jitter spreads the retries out so the quota can recover.

## Edge cases and pitfalls
- Retrying a throttled write (Create, Delete) is safe; retrying is only dangerous for non-idempotent calls, which AWS APIs mostly are not.
- Some throttles come from a shared quota across all your tooling; one noisy script can throttle your deploys.
- Do not "fix" throttling by requesting a quota increase for a retry storm; fix the client first, then measure.
- Cross-account or cross-region calls have separate quotas; the throttle may be in the assumed role's account, not yours.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_mufS8GBwRVhPOa3MwS3bhQ