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

{"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.