# Docker Image Tag Monitor - Digests & Platform Changes

Monitor exact Docker Hub image tags for digest, architecture and size changes. Compare saved observations before updating a deployment. Public metadata only; no image downloads.

Canonical product page: https://mayd-it.com/data-tools/actors/docker-image-tag-monitor/

## Example input

```json
{
  "imageTags": [
    "library/node:lts"
  ],
  "maxResults": 5
}
```

## Full guide

# Docker Image Tag Monitor - Digests & Platform Changes

**See exactly which digest or platform metadata changed between observations without downloading container layers.**

Watch exact public Docker Hub tags for digest, architecture and size changes. Compare saved observations with source links and readable reports. No image downloads or registry credentials.

## Start in under a minute

1. Paste image tags into the first input field, or use the included sample.
2. Keep the five-result limit for your first run and choose **Start**.
3. Open **Observations**, **Scope and diagnostics**, or the **Readable run report** in Output. Export CSV or JSON from the dataset.

```json
{
  "imageTags": [
    "library/node:lts"
  ],
  "maxResults": 5
}
```

No source account, API key, paid proxy or extra subscription is required for these public endpoints. Source availability and rate limits still apply.

## Who this helps

Platform teams reviewing mutable tags before builds or deployments.

## What you receive

One row per unique confirmed observation. Every row includes a stable `recordId`, title, source URL and observation time.

| Field | Meaning |
|---|---|
| `repository` | Source-reported repository; missing optional values remain null. |
| `tag` | Source-reported tag; missing optional values remain null. |
| `digest` | Source-reported digest; missing optional values remain null. |
| `lastPushedAt` | Source-reported last pushed at; missing optional values remain null. |
| `sizeBytes` | Source-reported size bytes; missing optional values remain null. |
| `platformCount` | Source-reported platform count; missing optional values remain null. |
| `platforms` | Source-reported platforms; missing optional values remain null. |
| `comparisonStatus` | not_requested, new, changed or unchanged |
| `changedFields` | Fields different from your last saved observation |
| `previous` | Previous saved source values when comparison is enabled |

## Saved comparisons

Enable **Compare with saved observations**, choose a snapshot name, and reuse the same input scope. The first run establishes history; it cannot report changes before that point. Enable **Save only new or changed observations** for later runs if you want a change-only export. An unchanged run can correctly save zero rows.

Only confirmed saved rows advance history. A bounded or failed run never establishes that a missing record was deleted. History is stored in a named key-value store in the running user's account. Use one writer per snapshot: do not overlap runs against the same snapshot. Change the snapshot name when starting a new independent workflow.

## Scope and limitations

Exact Docker Hub tags, current metadata only. Platform entries with unknown OS or architecture are preserved. No image layers, vulnerability scan or supply-chain safety verdict.

At most ten input values and thirty saved rows per run. Each input performs one bounded public API request. Responses are capped at 8 MiB and share the run deadline. No authentication bypass, image/package download or code execution is performed. HTTP 429 stops further requests; Stack Exchange backoff/quota signals are respected. Source failures appear in SUMMARY and the HTML report, never as paid data rows.

## Pricing

The configured base price is **$0.001 per saved observation**, plus **$0.00005 per start** at the default memory. Five observations cost $0.00505 at that base rate. Applicable plan discounts and the Store pricing panel govern actual charges. Set a maximum charge in Run options. Diagnostics, reports and unchanged skipped rows are not dataset result events.

## Make it recurring

Save an Actor task with your inputs, then attach an Apify Schedule. For change detection, keep the same snapshot and avoid overlapping runs. Add an integration to deliver results to your own spreadsheet or workflow. No external delivery is enabled automatically.

## Examples

1. **Image tags: library/node:lts** — A bounded library/node:lts observation sample. Review source evidence and export rows or compare them in a later run.
2. **Image tags: library/python:3.12-slim** — A bounded library/python:3.12-slim observation sample. Review source evidence and export rows or compare them in a later run.
3. **Image tags: library/nginx:stable** — A bounded library/nginx:stable observation sample. Review source evidence and export rows or compare them in a later run.

## Source and support

[Official source documentation](https://docs.docker.com/reference/api/hub/latest/). This independent Mayd IT tool is not affiliated with the source platform. Open an Actor issue with the run ID and expected result, or contact bmay@mayd-it.com. Never include credentials.