AppFolio Common Errors

Overview

AppFolio's Stack API powers property management integrations for tenant screening, work orders, lease management, and accounting. Each portfolio operates under its own subdomain ({company}.appfolio.com), meaning a single integration may need to handle multiple base URLs. Errors commonly stem from authentication misconfiguration, incorrect base URLs per portfolio, and business logic violations like duplicate tenant records or conflicting lease dates. Tenant lookup failures (404) are the most frequent issue, typically caused by targeting the wrong portfolio subdomain. This reference covers HTTP-level failures, property-management-specific validation errors, and recovery patterns for the most frequently encountered issues.

Prerequisites

A redacted incident record containing the portfolio identifier, endpoint, status code, request correlation ID, and time window; never copy tenant or lease payloads into a shared ticket.
Access to the correct sandbox or production portfolio endpoint and a credential owner who can rotate or validate credentials without exposing them in logs or command arguments.
A bounded retry policy, an idempotency mechanism for writes, and a known operator escalation path for uncertain tenant, lease, or work-order state.

Instructions

Classify the response by authentication, rate-limit, validation, or server failure and preserve only the redacted diagnostic fields.
Verify the portfolio base URL before changing credentials or retrying a 404; a valid tenant ID in another portfolio is not evidence of absence.
For 409 or partial write failures, query the canonical record and use the operation’s idempotency key or operator review before issuing another write.
Honor Retry-After for 429 and stop after the configured retry budget; pause the batch on 5xx or unknown write outcomes.

Error Reference

Code	Message	Cause	Fix
`401`	`Unauthorized`	Invalid or rotated client_id/secret pair	Regenerate credentials in AppFolio Stack partner portal
`403`	`Forbidden`	Account not approved as Stack partner	Complete partner application at appfolio.com/stack
`404`	`Tenant not found`	Wrong portfolio base URL or deleted tenant	Verify base URL is `{company}.appfolio.com/api/v1`
`409`	`Lease conflict`	Overlapping lease dates for same unit	Check existing leases on unit before creating new one
`422`	`Validation failed`	Missing required fields on work order or tenant	Include all required fields: `unit_id`, `description`, `priority`
`429`	`Too Many Requests`	Exceeded 120 requests/minute limit	Implement exponential backoff starting at 1s delay
`500`	`Internal Server Error`	AppFolio platform issue	Retry after 30s; check status.appfolio.com
`503`	`Service Unavailable`	Maintenance window (typically weekends)	Retry with backoff; subscribe to maintenance calendar

Error Handler

interface AppFolioError {
  code: number;
  message: string;
  category: "auth" | "rate_limit" | "validation" | "server";
}

function classifyAppFolioError(status: number, body: string): AppFolioError {
  if (status === 401 || status === 403) {
    return { code: status, message: body, category: "auth" };
  }
  if (status === 429) {
    return { code: 429, message: "Rate limit exceeded", category: "rate_limit" };
  }
  if (status === 404 || status === 409 || status === 422) {
    return { code: status, message: body, category: "validation" };
  }
  return { code: status, message: body, category: "server" };
}

Debugging Guide

Authentication Errors

AppFolio uses HTTP Basic Auth with client_id:client_secret. Verify credentials are not URL-encoded. Each portfolio has its own base URL -- confirm you are targeting the correct {company}.appfolio.com subdomain. Credentials rotate on partner approval changes.

Rate Limit Errors

The Stack API enforces 120 requests/minute per API key. Batch tenant lookups instead of individual calls. Use Retry-After header value when present. Bulk endpoints (e.g., /properties?page=1&per_page=100) reduce call count significantly. Rate limits are per-key, not per-portfolio, so multi-portfolio integrations share the same budget.

Validation Errors

Work order creation requires unit_id, description, and priority. Tenant creation requires first_name, last_name, and email. Lease creation fails with 409 if dates overlap an existing active lease on the same unit -- query current leases first. Move-in and move-out dates must be valid ISO 8601 format. Unit IDs are portfolio-specific and cannot be reused across subdomains.

Error Handling

Scenario	Pattern	Recovery
Tenant lookup returns 404	Search by email before creating	Use `/tenants?email=` endpoint
Work order 422	Missing priority field	Default to `normal` if unspecified
Lease date conflict	Overlapping active lease	End existing lease before creating new
Bulk import partial failure	Some records rejected	Parse error array, retry failed records only
Auth token expired mid-batch	401 on subsequent calls	Re-authenticate and resume from last offset

Quick Diagnostic

# Verify API connectivity without placing Basic Auth credentials in argv.
NETRC_FILE="$(mktemp)"
trap 'rm -f "$NETRC_FILE"' EXIT
chmod 600 "$NETRC_FILE"
APPFOLIO_HOST="${APPFOLIO_BASE_URL#https://}"
printf 'machine %s login %s password %s\n' "$APPFOLIO_HOST" \
  "$APPFOLIO_CLIENT_ID" "$APPFOLIO_CLIENT_SECRET" > "$NETRC_FILE"
curl -s -o /dev/null -w "%{http_code}" --netrc-file "$NETRC_FILE" \
  "${APPFOLIO_BASE_URL}/api/v1/properties"

Output

A redacted classification of the failure and the verified portfolio context
A bounded recovery decision: correct configuration, delay/retry, reconcile, rotate through the credential owner, or escalate an unknown write result
An incident receipt that identifies the affected batch without retaining tenant, lease, or credential data

Examples

When a work-order import receives 429, stop dispatching new records, retain the batch cursor and idempotency keys, and wait for the server-provided retry window before resuming at the same record. For a 409 lease conflict, query the unit’s current lease through the correct portfolio and route the result to an authorized operator rather than ending or replacing a lease automatically. If the follow-up read is unavailable or the outcome of a prior write is unknown, quarantine that record and continue only with unrelated safe work.

Resources

Next Steps

See appfolio-debug-bundle.