Troubleshooting HubSpot Data Migration: Fixing "HTTP 429 Too Many Requests" and Sync Crashes
Fix HubSpot data migration crashes, HTTP 429 rate limits, and 400 property validation errors by implementing batch APIs, exponential backoff, and strict schema
- HTTP 429 (Ten second rolling limit reached) is the most common cause of HubSpot migration crashes and stalled pipelines.
- HTTP 400 (Property values were not valid) occurs when mapping front-end labels instead of internal enumeration values, or passing invalid millisecond timestamps.
- Switching from single-object endpoints to the Batch CRM API increases throughput by 100x and drastically reduces rate limit exceptions.
- Implement robust exponential backoff and jitter in your API middleware to handle transient 5xx errors and strict API quotas.
| Migration Method | When to Use | Throughput/Time | Crash Risk |
|---|---|---|---|
| Single Object API (/crm/v3/objects) | Real-time event syncing (e.g., form submissions, single user updates). | Slow (1 record per request) | High (Easily hits 429 Rate Limits) |
| Batch Operations API (/batch/create) | Initial data migrations, nightly syncs, cron jobs. | Fast (100 records per request) | Low (Optimized for throughput) |
| Import API (Bulk CSV/JSON Import) | Massive historical data imports (Millions of records). | Very Fast (Asynchronous processing) | Moderate (Requires strict file formatting) |
| Third-Party Middleware (Zapier/Make) | Low-code setups lacking dedicated DevOps support. | Variable (Depends on platform limits) | Moderate (Silent failures common) |
Understanding the Error
When executing a HubSpot data migration, DevOps engineers and system administrators frequently encounter pipeline crashes, stalled syncs, and outright integration failures. The symptoms often manifest as 'HubSpot not working' or 'HubSpot crash' from the end-user perspective. However, on the backend, these incidents are almost always tied to specific REST API exceptions, most notably HTTP 429 Too Many Requests or HTTP 400 Bad Request: Property values were not valid.
A migration 'crash' in an enterprise environment usually indicates an unhandled exception in your middleware, or a total exhaustion of the available API quota, causing the configuration to break and the data synchronization to halt. Understanding the nuances of HubSpot's API architecture—specifically its strict rate limits and strongly-typed CRM property schema—is critical for advanced troubleshooting.
Step 1: Diagnose the Failure Point
Before rewriting your migration scripts or altering your HubSpot configuration, you must pinpoint exactly why the pipeline is failing. The first step is isolating the error payload returned by the HubSpot API.
- Check the Integration Logs: Review your middleware (e.g., MuleSoft, AWS Lambda, Python/Node.js microservices) for raw HTTP responses. Look specifically for 4xx and 5xx status codes.
- Audit the API Usage Dashboard: Navigate to HubSpot > Settings > Integrations > API Key / Private Apps to monitor your daily and minutely API call volume. Spikes here correlate directly to migration script executions.
- Inspect Payload Schemas: A very common cause of 'HubSpot not working' during data imports is pushing generic string data into strongly-typed fields like dates, custom enumerations, or booleans.
Step 2: Fix HTTP 429 Rate Limit Exhaustion
The most pervasive cause of a stalled or 'crashing' HubSpot migration is hitting the rate limit. HubSpot enforces a strict limit depending on your account tier (e.g., 100 requests per 10 seconds for standard tiers, up to 150 for Enterprise). When breached, the API immediately severs the connection and returns:
{"status":"error","message":"Ten second rolling limit reached","correlationId":"...","category":"RATE_LIMITS"}
The Solution: First, implement a robust HTTP retry mechanism with exponential backoff and jitter. This ensures that when a 429 is encountered, your script pauses and tries again rather than throwing a fatal exception.
Second, and more importantly, shift your architectural approach from single-object endpoints (POST /crm/v3/objects/contacts) to Batch APIs (POST /crm/v3/objects/contacts/batch/create). Batching allows you to process up to 100 CRM records per single API call. This effectively increases your throughput by 100x without consuming additional API quota.
Step 3: Resolving HTTP 400 Property Errors
When migrating data from legacy CRM systems (like Salesforce, Microsoft Dynamics, or bespoke internal databases) to HubSpot, schema mismatches are inevitable. The error payload usually looks like this:
{"status":"error","message":"Property values were not valid","correlationId":"...","category":"VALIDATION_ERROR"}
The Solution:
- Internal Values vs. Labels: For dropdown select or multiple checkbox properties, ensure you are passing the internal value of the enumeration, not the front-end label. (e.g., passing
new_leadinstead ofNew Lead). - Date Formatting Constraints: HubSpot expects dates to be formatted as midnight UTC in milliseconds since the epoch. Passing standard ISO-8601 strings (e.g.,
2023-10-01T12:00:00Z) to date properties will immediately trigger a 400 error. You must convert your timestamps locally before payload transmission.
Step 4: Authentication and Configuration Drop-offs
If your script suddenly loses access entirely and reports 401 Unauthorized or INVALID_GRANT, the issue lies in your OAuth configuration. While Private App Access Tokens (PATs) are static and easier to manage for internal scripts, standard OAuth integrations require continuous token cycling.
The Solution: Ensure your application logic anticipates the brief 30-minute lifespan of HubSpot Access Tokens. Implement a background worker or middleware interceptor that securely requests a new access token using the Refresh Token 5 minutes prior to expiration. This process should lock the execution thread for other migration workers until the new token is acquired and safely distributed across your instances.
Frequently Asked Questions
import requests
import logging
from requests.adapters import HTTPAdapter
from urllib3.util.retry import Retry
# Configure resilient HubSpot API Client for Data Migration
HUBSPOT_ACCESS_TOKEN = "pat-na1-xxxx-xxxx-xxxx"
HUBSPOT_API_BASE = "https://api.hubapi.com/crm/v3"
def get_hubspot_session():
session = requests.Session()
# Configure exponential backoff for 429 Rate Limits and 5xx errors
# This prevents the migration script from crashing during quota limits
retries = Retry(
total=5,
backoff_factor=2, # Sleeps for 2, 4, 8, 16, 32 seconds on consecutive failures
status_forcelist=[429, 500, 502, 503, 504],
allowed_methods=["POST", "PUT", "PATCH", "DELETE", "GET"]
)
adapter = HTTPAdapter(max_retries=retries)
session.mount("https://", adapter)
session.mount("http://", adapter)
session.headers.update({
"Authorization": f"Bearer {HUBSPOT_ACCESS_TOKEN}",
"Content-Type": "application/json"
})
return session
def batch_create_contacts(contacts_data):
session = get_hubspot_session()
url = f"{HUBSPOT_API_BASE}/objects/contacts/batch/create"
# HubSpot batch API allows a maximum of 100 records per request
batch_payload = {"inputs": contacts_data[:100]}
try:
response = session.post(url, json=batch_payload)
response.raise_for_status() # Will raise HTTPError for 400 Bad Request
logging.info(f"Successfully migrated {len(batch_payload['inputs'])} contacts.")
return response.json()
except requests.exceptions.HTTPError as e:
logging.error(f"HubSpot Data Migration Exception: {e.response.text}")
raise
# Example execution for troubleshooting
if __name__ == "__main__":
mock_migration_data = [
{"properties": {"email": "test1@example.com", "firstname": "Sys", "lastname": "Admin"}},
{"properties": {"email": "test2@example.com", "firstname": "Dev", "lastname": "Ops"}}
]
# batch_create_contacts(mock_migration_data)Error Medic Editorial
Error Medic Editorial comprises senior Site Reliability Engineers and DevOps architects dedicated to diagnosing and solving enterprise integration failures, API pipeline crashes, and scalable system configurations.