API Request limitation via Postback (Service Request API Service Guide)

Schwab

• Maximum page size: 14x14 inches.
• The Service Request can have up to 10 files in a single request (as long as the total size of the request is under 10MB); Combination of Attachments + Schwab: Custodian Forms/Optional Forms.
• If a firm has more documents that they want to send, they would need to do a second Service Request.

Fidelity

• Max of 20MB: Attachments + Fidelity: Custodian Forms/Optional Forms.
• Less than 30 Attachments
• Under 499 pages per file

 
Pershing

• Max of 20MB per file