How to send a check with Flex.
A guide to mailing a real paper check from your Flexaccount — with premium options like Certified, Priority, and Express Mail that your bank doesn't offer.
Flex bill pay vs. Check Supply.
See how Check Supply compares with Flex's traditional bill-pay rails. Unlike your bank, Check Supply offers premium mail options — Certified, Priority, and Express — alongside faster processing and real-time tracking.
| Feature | Flex bill pay | Check Supply |
|---|---|---|
| Processing time | 3–5 business days | Same day (before 3 PM ET) |
| Delivery time | 5–7 business days | 1–5 business days |
| Mobile app | Limited mobile features | Full iOS app |
| Tracking | Limited | Real-time status + receipts |
| Setup | Online banking enrollment | Two-minute Plaid flow |
| Certified Mail | Not available | Available · signature + tracking |
| Priority Mail | Not available | Available · 1–3 days with tracking |
| Express Mail | Not available | Available · 1–2 day delivery |
Flex
Flex is supported by Check Supply for secure check mailing with premium delivery options.
Mailing a check from Flex in under four minutes.
With Check Supply, you get access to premium mail options like Certified, Priority, and Express Mail that Flex doesn't offer. Whether you prefer your iPhone or a desktop browser, you can handle the full flow quickly, securely, and without any hassle.
Disclaimer: this page is an independent guide by Check Supply and is not affiliated with Flex.
Zelle at Flex.
Zelle support for Flex is still being reviewed
Zelle support for Flex is not confirmed in the latest mapped dataset. Check Flex's official site or the Zelle enrollment directory before relying on Zelle for this institution, or use Check Supply to send the payment by mailed check.
Use Check Supply to send payments that do not fit Zelle's availability or transaction limits.