The bank on the edge of town was haunted - or at least, that's what folks often said.

Most days, the bank's software worked just fine. But on nights when the moon was full, and the wind rustled in the leaves, and everything felt not-quite-right, things sometimes went very, very wrong.

On one chilly fall evening, the team was wrapping up after a busy day. Susan, one of the developers on the team, had tickets to see a movie at the theater in town. Her final task before leaving was to prepare the account balances file, which had to be uploaded so that transactions could be processed overnight.

When the files were ready, Susan connected to the SFTP server and started the upload.

"Need any help?" one of her colleagues asked.

"I'm all set," said Susan. "Just waiting on this file to upload, it shouldn't take more than a few minutes."

As the last of her colleagues filed out the door, a warning popped up on Susan's monitor.

UPLOAD FAILED

"Weird," Susan muttered to herself. She double checked the selected file, and tried again.

UPLOAD FAILED

Her computer was connected to the network, the server was online, and she'd never had an issue with this process before. Susan checked the time and realized with frustration that she'd miss the previews, but might still be able to make it in time for the movie's opening credits.

UPLOAD FAILED

A few miles away, previews had ended and the movie was just starting. Although the theater was relatively crowded, Susan's seat sat empty.

UPLOAD FAILED

A light breeze had picked up outside, rustling dry autumn leaves. Moonlight spilled through the office window.

UPLOAD FAILED

The Real Story#

While Susan is fictional, her haunting tale is drawn largely from truth. The story is based on a financial institution that migrated its daily sweep process to Temporal.

The financial institution–let's call them Money Co. to keep it simple–was using SFTP file uploads and downloads several times each day to communicate account balances and transfers between accounts with other financial institutions in their network. While this approach met regulatory needs and generally got the job done, a number of issues regularly caused headaches for Money Co. employees, including:

• Uploads and downloads failed frequently, often requiring human intervention to fix.
• The SFTP server would get overwhelmed with requests regularly, meaning the Money Co. team needed to pause operations until the server recovered.
• Queries related to these operations could fail if the database was under heavy load.
• To make matters worse, Money Co.'s own internal systems were not resilient to delays introduced by the above issues, and the engineering team often found themselves scrambling to fix issues in time to meet strict deadlines.

For a more detailed exploration of this story, please see Increasing Resiliency in a Banking Sweep System: Incremental migration to a Temporal Workflow

Migrating these operations to Temporal allowed the Money Co. team to take advantage of Temporal's event history to help investigate the cause of any errors going forward. The migration itself was rolled out incrementally, allowing for intentional changes to roll out over time. Ultimately, migrating to Temporal delivered positive impact immediately, and ensured a more stable and resilient foundation for the future.

Ready to try Temporal yourself? Set up your local environment in under 10 minutes with our quick start guide.