Bank Connectivity 101: APIs vs. Secure File Transfer—Choosing the Fastest, Safest Path for Treasury Data

A Treasury Management System is only as strong as its pipes: if account data doesn’t flow in cleanly, every report, forecast, and payment run is built on sand. Today there are two proven ways to move that data from your banks into a TMS—real-time APIs and secure file transfer—and each comes with unique strengths and trade-offs.

Two Roads, One Destination

API connections feel like dedicated fiber lines straight into a bank’s core. Authorize once, and balances or transactions can refresh every few minutes. They’re incredibly fast to set up—often the same day a customer signs—and impose almost no burden on internal IT teams. Where APIs exist, they deliver near-live visibility that treasury teams love.

Yet those sleek highways don’t reach every address. Enterprise portals such as JPMorgan Access or Bank of America CashPro expose limited or no API access, and even mid-tier banks may throttle traffic or skip features like historical backfill, lockbox details, or wire initiation. The result is a patchwork: real-time for some accounts, “call your relationship manager” for others.

Secure file transfer (SFTP), by contrast, is the all-weather road system finance has relied on for decades. Every bank in the United States can deliver a BAI2, CAMT 053, or MT940 file—community institutions included—and those files hold the richest possible data set (ACH, wires, lockbox, virtual accounts, positive-pay exceptions, you name it). Once live, file specs change rarely, so the feed just runs.

The flip side is time: file programs require enrollment forms, SSH key exchange, firewall tweaks, and testing cycles. Go-live can take a few weeks, and files typically arrive once or a handful of times per day rather than every few minutes.

Security Is Non-Negotiable

Whether your data travels through an API or over SFTP, encryption is mandatory. APIs rely on HTTPS/TLS and OAuth scopes to enforce least-privilege access; SFTP rides on SSH with optional PGP file encryption and digital signatures to prove integrity. At Arpari, all credentials live in a vault, keys rotate automatically, and every incoming payload—file or API call—is validated before being ingested.

Arpari’s Connectivity Philosophy: Plan First, Plug In Second

Many treasury vendors ink the contract and worry about connectivity afterward, only to discover critical accounts that no modern API can reach. That delay ends up on your timeline. Arpari does the reverse: during discovery we map every bank, portal, and required file or API, then produce a connectivity blueprint so you know exactly how each account will flow before onboarding starts.

• APIs wherever they make sense—regional or digital-first banks that already publish robust endpoints can be live the same week.
• Files for universal coverage—when APIs fall short, Arpari stands up BAI2 or ISO 20022 feeds instead, guaranteeing you never lose an account because of a technical gap.

File Transfer, Soup to Nuts—and Free

Implementing file connectivity can feel daunting, so Arpari takes it off your plate entirely. We draft and submit enrollment paperwork, generate and manage SSH keys, handle firewall allow-listing with your IT team, coordinate test files, and tune the parser—start to finish. Unlike many providers who charge “professional-services” fees for this work, Arpari treats it as part of standard onboarding: no surprise invoices, ever.

A Hybrid Model That Covers Every U.S. Bank

Because we blend real-time APIs with bullet-proof file transfer, Arpari can connect to any commercial bank in the United States—from the largest money-center institution to the smallest community lender—without compromising speed or completeness. Your dashboard looks identical whether data arrived at 10:02 a.m. via API or at 8:00 p.m. in a CAMT 053 file, so your treasury workflows never have to care how the bytes got there.

What an Implementation Really Looks Like

While API accounts often light up in a day, file integrations run on their own track: enrollment paperwork within a week, key exchange and firewall work in another, test cycles right after. Because the two paths progress in parallel, most customers see live cash flowing from at least some banks during week one, with any slower, file-based feeds following a few weeks later. The net effect is quick wins without leaving stragglers behind.

Ready to see how every dollar can be visible—no matter where you bank? Book a 30-minute demo at arpari.com/demo and let’s build your connectivity blueprint before you ever sign. With Arpari, the road to real-time treasury data is secure, complete, and free of implementation surprises.

Arpari is the modern treasury platform built for real-estate owners, operators, and finance teams who demand instant, accurate cash visibility. We aggregate bank data, automate cash reporting, and let you move money securely—all in one place.