The merchant category code is a 50-year-old lookup table that modern spend controls still depend on. This post explains how it works, where it leaks, and what replaces it.

We’re not going to sell you on the benefits of sending checks. If you’re sending checks in 2026, you’re doing it because you have to.

Changes for 2026 Q1, including the Entity Onboarding Sessions API, 3D Secure, Push Provisioning, Event polling, IP-restricted API keys, and a C# SDK.

At Increase, the engineers who build the system also support it. This post explains why we skip the traditional support team, and what that means for the customers working with us.

We're honored that Forbes named Increase to its annual Fintech 50 list for the second year in a row.

Changes for 2025 Q4, including FedNow, Push-to-Card, Cards Disputes API, Push Provisioning, Check Transfer enhancements, PHP and Ruby SDKs, Dashboard and Status Page improvements, and LLM-friendly documentation.

Small‑business lending bifurcated over the last decade.

Agents based on large language models are doing more and more for us. Empowering them to make payments on our behalf is a live frontier.

Embedding financial services in industry-specialized software is good for customers, good for software companies, and good for banks. But to do it well, you need direct access to banking fundamentals and a willingness to understand how money actually moves.

Changes for 2025 Q2, including API event log filtering, Event page improvements, Check Transfer enhancements, and more.

Check is a leading embedded payroll infrastructure, giving businesses the ability to integrate payroll directly into their platforms. Whether those platforms are designed for coffee shops or construction companies, Check ensures their payroll operations run efficiently – supporting thousands of businesses and hundreds of thousands of employees. Their mission is to simplify payroll, making it seamless, scalable, and accessible to platforms of all shapes and sizes. However, achieving this goal requires more than functional software—it depends on having high visibility into the underlying financial networks and access to faster payment methods, areas where traditional banking partnerships can fall short.

Learn more about what goes into building a bill pay program with Increase.

Changes for 2025 Q1, including File Links, check deposit images, Apple Pay transaction history, and more.

Ascend is a leading finance automation platform in the insurance industry, streamlining the entire payment lifecycle, from collection and accounting to reconciliation and disbursement. By automating these processes, Ascend helps insurance businesses simplify treasury management, eliminate repetitive, time-consuming operational tasks, and provide a better customer experience. The result is greater profitability for its customers which include leading agencies, MGAs, and insurance carriers.

As an engineer, how do you ensure that a code change doesn’t inadvertently break a compliance or legal obligation? More fundamentally, how do you even know what those obligations are? Conway’s Law tells us that compliance and engineering teams tend to operate in separate systems that rarely talk to each other. As a result, policies, procedures, and legal frameworks live in one world, while production systems live in another.

Ramp is a financial operations platform that helps companies achieve more by spending less. From spend and expense management to bill payments and vendor management, Ramp’s all-in-one solution is designed to automate finance operations and help businesses grow efficiently. With the launch of the Ramp Treasury, Ramp has further expanded its suite of financial tools, offering an all-in-one cash and treasury portfolio that puts customers’ operating cash to work.

Changes for 2024 Q4, including OAuth applications, lockboxes, export functionality, and more.

ISO 8583 is the standard for real-time messages communicated between acquirers and issuers through all of the major card networks. Whenever you tap your card at a point of sale device or click “purchase” online, odds are it will eventually end up as an ISO 8583 message sent between the merchant’s acquiring processor, the card network, and your bank’s issuer processor.

Increase operates as a parallel core for our bank partners. We connect directly to the Federal Reserve and process wires, ACH transfers, and checks using a dedicated routing number. An important associated responsibility is to reconcile the activity in our systems with the cash movement at the Federal Reserve.

Changes for 2024 Q3, including RSS feed subscription, card authorization improvements, Real-Time Payments, and more.

In 2012, Stripe had an incident where a file sent to a financial partner wasn’t acknowledged. This went unnoticed, leading to a delay in transferring what seemed like a significant amount of money at the time. During the debrief, it became clear that we needed more robust automated monitoring and alerting for our financial partner integrations. In the next day or so, Patrick and Siddarth built an invariant monitor.

From the Fresno drop in 1958 and through Visa’s first 15 years of existence, an authorization with a Visa card was processed by having the merchant call either the cardholder’s bank, if the card was regional, or a switching center to be forwarded onto the bank if it was not. In the early 70s, the overhead of this reached a breaking point and Visa set out to build what would become known as “BankAmericard Authorization System Experimental (BASE)”—an electronic authorization system linking the Visa member banks with merchants or their acquiring centers through a central switching system.

A financial institution can maintain its existing core while simultaneously adding a new core. The two cores can interact as necessary (either by exchanging data directly or separately interacting with upstream or downstream services). This is what Increase does: we operate as a parallel core for our bank partners. We also expose functionality of the underlying depository rails via powerful APIs.

Increase’s API and Dashboard allow efficient, programmatic access to mail checks, deposit check images, and — starting this month — host a virtual mailbox to accept payments in your designated check lockbox.

Changes for 2024 Q2, including check deposit images, card dispute timelines, lockboxes, and more.

Learn about the foundational design principle of Increase’s API and how it helps us model the inherent complexity of the underlying financial networks we work with.

Automated Clearing House (ACH) is the dominant low-value transfer mechanism in the US. Learn more about how ACH works and pitfalls to avoid.

Changes for 2024 Q1, including Program ID exposure, Visa fraud scores, Quickbooks integration, and more.

CapitalOS offers embedded spend management solutions for B2B platforms looking to launch card-based products for their users. As B2B platforms increasingly become the operating system for small businesses, they’re uniquely positioned to save time and money for their users through smart spend management.

Increase and our bank partners now offer access to Federal Deposit Insurance Corporation (“FDIC”) coverage on deposits of more than $250,000. This works through our connection to a deposit placement network offered by IntraFi. You can place deposits using IntraFi’s ICS service via Increase’s Dashboard or API. Enrollment does not impact access to your funds.

We first wrote an internal culture document at Increase on 2019-10-09. It was labeled as a draft since we weren’t sure what principles would hold true as we scaled. Now, 4 years later, we’ve found the way that we work allows us to process tens of billions in payments.

Changes for 2023 Q4, including Wire Transfer limits, Check Deposit timing, IntraFi enrollment, and more.

Fedwire is the dominant high-value transfer mechanism in the US and is the Federal Reserve’s real-time gross settlement network. Learn more about how Fedwire works and pitfalls to avoid.

Ramp is the ultimate platform for modern finance teams. From spend management and expense management software, to bill payments and vendor management, Ramp’s all-in-one solution is designed to automate finance operations and build healthier businesses.

Changes for 2023 Q3, including API documentation improvements, physical card simulations, check image reviews, and more.

Real-Time Payments is an instant payment service developed by The Clearing House. It reaches roughly 71% of US depository accounts. Learn more about how Real-Time Payments work and pitfalls to avoid.

Changes for 2023 Q2, including Transactions vs Transfers guide, documentation refactoring, and more.

Check 21 is the Federal Reserve’s electronic check clearing service. Learn more about how Check 21 works and pitfalls to avoid.

Changes for 2023 Q1, including Programs introduction, wire transfer requirements, SDK launches, and more.

Changes for 2022 Q4, including general availability launch, Real-Time Payments API, Check Transfer improvements, and more.

Changes for 2022 Q3, including check numbers, Real-Time Payments simulation, company creation flow, and more.

Changes for 2022 Q2, including wire routing details, stop payment functionality, Cards API launch, and more.