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Frequently Asked Questions

Quick Start​

How do I get an API Key?​

  1. Visit Developer Console
  2. Register or log in
  3. Create a new key on the API Keys page

New users get 1,000 free API call quota right away.

What data formats are supported?​

  • ECG data: float arrays (the unit is recommended to be mV)
  • PPG data: integer or float arrays
  • Sampling rate: recommended 250Hz–1000Hz, best at 500Hz
  • Duration: shortest 10 seconds, recommended 10–40 seconds

How can I ensure data quality?​

  1. Keep good electrode contact during acquisition
  2. Avoid interference from intense movement
  3. Use the recommended sampling rate (500Hz)
  4. Check data completeness before sending

API Usage​

Why do I get a 401 error when calling the API?​

Cause: the API key is invalid or was not passed correctly.

Solution:

  1. Double-check that your API key was copied correctly
  2. Confirm the header format: Authorization: Bearer YOUR_API_KEY
  3. Check whether the key has expired or been deleted

Why do I get a 429 error when calling the API?​

Cause: rate limiting was triggered.

Solution:

  1. Reduce request frequency
  2. Implement exponential backoff retries
  3. Upgrade to a higher-tier plan

The analysis confidence is low​

Possible reasons:

  • Poor signal quality (noise, artifacts)
  • Data duration is too short
  • Sampling rate is set incorrectly

Recommendations:

  1. Check the acquisition device
  2. Increase data duration
  3. Confirm that the samplingRate parameter is correct

Account & Billing​

What if I run out of free quota?​

Three options:

  1. Wait for the daily automatic reset (at 00:00 each day)
  2. Upgrade to the Advanced plan
  3. Contact sales/business to purchase additional quota

How do I check my current usage?​

  1. Log in to the Developer Console
  2. View the usage statistics on the Overview page

What payment methods are supported?​

  • Alipay
  • WeChat Pay
  • Bank transfer
  • Company-to-company transfer (VAT invoices available)

Can I apply for an invoice?​

Yes. In the console, apply from the Billing page. We support:

  • VAT ordinary invoices
  • VAT special invoices

Still have questions?​

  • 📧 Technical support: contact@heartvoice.com.cn
  • ☎ Cooperation hotline: 400-0551-927
  • 📱 Phone: 18055165745 (Qi Manager)