# ArcGIS Field & Domain Change Monitor (`quietdatatools/arcgis-field-domain-change-monitor`) Actor

Monitor public ArcGIS FeatureServer fields and coded/range domains for type, code-label, nullability and length changes. Persistent before/after metadata, exact required-field checks and safe history on failures. No feature row download.

- **URL**: https://apify.com/quietdatatools/arcgis-field-domain-change-monitor.md
- **Developed by:** [QuietDataTools](https://apify.com/quietdatatools) (community)
- **Stats:** 2 total users, 1 monthly users, 100.0% runs succeeded, 0 bookmarks
- **User rating**: No ratings yet

## Pricing

$0.01 / successful schema check

This Actor is paid per event. You are not charged for the Apify platform usage, but only a fixed price for specific events.

Learn more: https://docs.apify.com/actors/running/actors-in-store.md#pay-per-event

## What's an Apify Actor?

An Actor is a serverless cloud program that runs on the Apify platform. It has two run modes.
In Batch mode, an Actor accepts a well-defined JSON input, performs an action which can take anything from a few seconds to a few hours,
and optionally produces a well-defined JSON output, datasets with results, or files in key-value store.
In Standby mode, an Actor provides a web server which can be used as a website, API, or an MCP server.

Apify vocabulary and the platform model are defined once, in the agent quickstart at https://apify.com/agents.md.

## How to integrate an Actor?

If asked about integration, you help developers integrate Actors into their projects.
You adapt to their stack and deliver integrations that are safe, well-documented, and production-ready.

Do not guess an integration path. Every one of them is in the agent quickstart at https://apify.com/agents.md: the Apify MCP server, Agent Skills with the Apify CLI, the JavaScript and Python clients, the REST API, and the account-free path for an agent with no human to sign in. It also carries the rule on stating cost before the first paid run.

For examples already wired to this Actor's own input schema, see the [API](#api) section below.

Each client library has reference documentation the quickstart does not restate: [JavaScript/TypeScript](https://docs.apify.com/api/client/js/docs.md) (`npm install apify-client`) and [Python](https://docs.apify.com/api/client/python/docs.md) (`pip install apify-client`).

# README

## ArcGIS Field & Domain Change Monitor

Catch changes to the public metadata contract your GIS pipeline depends on. Monitor one ArcGIS FeatureServer layer or nonspatial table for added/removed fields, field types, aliases, nullability, lengths, and coded-value or range-domain definitions. Persistent history returns exact previous/current values without downloading any features.

Designed for GIS analysts decoding coded values and teams maintaining recurring feature exports. A bulk exporter retrieves feature rows; this tool watches the field definitions and code-to-label mappings those workflows use.

### Quick start

```json
{"layerUrl":"https://services2.arcgis.com/FiaPA4ga0iQKduv3/arcgis/rest/services/blm_natl_admu_field_poly_webpub_A_view/FeatureServer/0","monitorName":"default","requiredFields":[],"includeUnchanged":true}
```

Run once to save a baseline, then repeat the same input or schedule checks. The example is a public BLM administrative-boundaries layer. Different monitor names have separate histories. Run only one check at a time per monitor.

### Output

Dataset rows have `status` BASELINE, ADDED, CHANGED, REMOVED or optional UNCHANGED; `fieldName`, `changes`, `compatibilityRisk`, `previous`, `current`, `sourceUrl`, `layerUrl`, `layerId`, `checkedAt`. Each snapshot includes type, alias, nullability, length and normalized domain. Number code 1 and string code "1" stay distinct. Code order and field order are ignored. A code's display label changing is still a domain change. Field identity is its exact name: a rename is removal plus addition, not guessed continuity.

Type, nullability, length, domain changes and removed fields are REVIEW_REQUIRED. Alias-only edits have NONE_DETECTED. These are review signals, not proof of compatibility or safety. OUTPUT in the run key-value store contains counts, previousCheckedAt, checkedAt, columnCount, requiredFieldsSatisfied and missingRequiredFields. Required names are case-sensitive API field names.

### Pricing

$0.01 per successful metadata check, including baseline and unchanged checks, with platform usage included. No per-field charge. Failed source checks preserve history and are not charged. A successful check with missing required fields still costs one check. Use a bounded timeout and charge cap.

### Scope and limits

Public unauthenticated HTTPS FeatureServer layer/table metadata only. No query parameters, tokens, private services, MapServer layers, feature rows, geometry downloads or editing. One metadata GET, 20-second source deadline, 2MB cap, up to500 fields, up to1000 codes per domain and100 required names. Only field-level null/codedValue/range domains; inherited/name-only/unknown domain formats fail safely. Subtype/type-specific domains, contingent values, relationships, unique ID definitions, geometry/spatial reference, row-value validity, freshness and complete breaking-change analysis are outside scope. A layer with subtype domains can still be checked for its field-level definitions; that is not complete domain coverage.

Malformed, empty, incomplete, error or mismatched responses fail without treating fields as removed. A successful full field list reports genuine removals immediately. Missing optional length/nullability is represented as unknown (null). Domain order is canonicalized; returned values reflect the publisher's metadata and can lag updates.

State is isolated by Apify user, Actor, URL and monitor name. Best-effort lease is not an atomic distributed lock. Output → charge → snapshot provides at-least-once behavior: interruption can repeat output or a charge. Aborted checks preserve the last committed snapshot. No reset/delete operation.

Independent tool, not affiliated with Esri or source publishers. Respect source terms and API limits. No profitability or zero-error guarantee.

# Actor input Schema

## `layerUrl` (type: `string`):

HTTPS FeatureServer/layerNumber URL, no token/query/fragment. Public layer or table metadata only.

## `monitorName` (type: `string`):

Keep the same name for repeat checks; different names have independent baselines.

## `requiredFields` (type: `array`):

Exact case-sensitive field names; missing fields are reported, not inferred from aliases.

## `includeUnchanged` (type: `boolean`):

Write UNCHANGED rows on successful repeat checks.

## Actor input object example

```json
{
  "layerUrl": "https://services2.arcgis.com/FiaPA4ga0iQKduv3/arcgis/rest/services/blm_natl_admu_field_poly_webpub_A_view/FeatureServer/0",
  "monitorName": "default",
  "requiredFields": [],
  "includeUnchanged": true
}
```

# Actor output Schema

## `fields` (type: `string`):

No description

## `summary` (type: `string`):

No description

# API

You can run this Actor programmatically using our API. Below are code examples in JavaScript, Python, and CLI, as well as the OpenAPI specification and MCP server setup.

## JavaScript example

```javascript
import { ApifyClient } from 'apify-client';

// Initialize the ApifyClient with your Apify API token
// Replace the '<YOUR_API_TOKEN>' with your token
const client = new ApifyClient({
    token: '<YOUR_API_TOKEN>',
});

// Prepare Actor input
const input = {
    "layerUrl": "https://services2.arcgis.com/FiaPA4ga0iQKduv3/arcgis/rest/services/blm_natl_admu_field_poly_webpub_A_view/FeatureServer/0"
};

// Run the Actor and wait for it to finish
const run = await client.actor("quietdatatools/arcgis-field-domain-change-monitor").call(input);

// Fetch and print Actor results from the run's dataset (if any)
console.log('Results from dataset');
console.log(`💾 Check your data here: https://console.apify.com/storage/datasets/${run.defaultDatasetId}`);
const { items } = await client.dataset(run.defaultDatasetId).listItems();
items.forEach((item) => {
    console.dir(item);
});

// 📚 Want to learn more 📖? Go to → https://docs.apify.com/api/client/js/docs

```

## Python example

```python
from apify_client import ApifyClient

# Initialize the ApifyClient with your Apify API token
# Replace '<YOUR_API_TOKEN>' with your token.
client = ApifyClient("<YOUR_API_TOKEN>")

# Prepare the Actor input
run_input = { "layerUrl": "https://services2.arcgis.com/FiaPA4ga0iQKduv3/arcgis/rest/services/blm_natl_admu_field_poly_webpub_A_view/FeatureServer/0" }

# Run the Actor and wait for it to finish
run = client.actor("quietdatatools/arcgis-field-domain-change-monitor").call(run_input=run_input)

# Fetch and print Actor results from the run's dataset (if there are any)
print(f"💾 Check your data here: https://console.apify.com/storage/datasets/{run.default_dataset_id}")
for item in client.dataset(run.default_dataset_id).iterate_items():
    print(item)

# 📚 Want to learn more 📖? Go to → https://docs.apify.com/api/client/python/docs/quick-start

```

## CLI example

```bash
echo '{
  "layerUrl": "https://services2.arcgis.com/FiaPA4ga0iQKduv3/arcgis/rest/services/blm_natl_admu_field_poly_webpub_A_view/FeatureServer/0"
}' |
apify call quietdatatools/arcgis-field-domain-change-monitor --silent --output-dataset

```

## MCP server setup

```json
{
    "mcpServers": {
        "apify": {
            "type": "http",
            "url": "https://mcp.apify.com/?tools=fetch-actor-details,quietdatatools/arcgis-field-domain-change-monitor"
        }
    }
}
```

The hosted server signs you in with OAuth on first connect, so no API token belongs in this config. Clients without OAuth support can send an `Authorization: Bearer <APIFY_API_TOKEN>` header instead, using a token from API & Integrations in Apify Console (https://console.apify.com/settings/integrations).

## OpenAPI specification

Download the OpenAPI definition: https://api.apify.com/v2/actors/Xc5eD72YwQwTCvQ98/builds/gZwiGffFrcci5xJfZ/openapi.json