By: Tommy Avers, Vice President of ISV at Celero Commerce

For most software companies, the decision to embed payments starts as a technical one. Someone on the product team researches APIs, compares documentation, and picks whatever seems easiest to integrate by the next sprint. That approach gets a payments feature live, but it rarely accounts for what the partnership actually looks like a year or two down the road, when support tickets pile up, merchants have questions, or the business scales into new verticals.

Choosing the right payments partner for ISVs is a decision that shapes merchant experience, support workload, and revenue for years to come. It deserves the same scrutiny ISVs apply to any other major vendor relationship. Having spent years working through these evaluations alongside ISV partners on the Celero Fusion team, here are five questions worth asking before signing anything.

How Well Documented Is the Integration Process?

Documentation quality tells you more about a partner than almost anything else available before you sign a contract. Can a developer get a working sandbox integration without needing to escalate to a sales rep or wait days for a callback? Are the API docs current, accurate, and written for the actual use cases ISVs face, or do they read like they were written for a different kind of customer entirely?

Poor documentation rarely stays a one time inconvenience. It tends to resurface every time your team needs to update something, troubleshoot an edge case, or onboard a new engineer. Those delays add up, and they pull time away from building the product your customers actually came for.

What Does Support Look Like After Going Live?

It is easy to evaluate a partner based on how responsive their sales team is during the pitch. It is much harder to know how responsive their support team will be once you are a live customer with real merchants depending on uptime.

Ask about this directly: What are typical response times for technical issues? Is there a dedicated point of contact, or does every ticket start from scratch with someone new? How are disputes, chargebacks, or merchant account issues handled, and how much of that burden falls back on your team versus theirs?

Support quality becomes most visible exactly when something goes wrong, which is exactly why it is worth vetting before that happens rather than after. A payments partner for ISVs that treats support as an afterthought will eventually make that clear, usually at the worst possible time.

How Is Revenue Share or Monetization Structured?

Every payments partnership involves some kind of economic arrangement, and the details matter far beyond the headline rate. Ask how revenue share is calculated, what could cause that structure to change over time, and how transparent the reporting is on an ongoing basis.

It is worth remembering that the goal is not just landing a favorable rate at signing. It is understanding the full economics well enough to protect your margin as your merchant base grows and your business changes shape.

How Does the Partner Support the Merchant Experience?

Software vendors sometimes forget that their merchants are, in a very real sense, also the payments partner’s customers. Onboarding speed, payout reliability, and how clearly issues get communicated when something goes wrong all shape how merchants feel about your platform, even though you are not the one processing the transaction.

A clunky or confusing merchant experience becomes your problem to solve, regardless of who is technically responsible for it. It is worth asking a prospective partner to walk through their actual onboarding flow and support process from the merchant’s point of view, not just yours.

How Will This Partnership Scale as the Business Grows?

It is easy to evaluate a partner based on what your business looks like today and harder to picture what you will need in two or three years. Will this partner support multiple entities or business models if you expand? What happens to pricing and support quality as your transaction volume grows? If international expansion is part of your roadmap, can this partner actually support it, or will that require a separate conversation entirely?

Switching payments partners after the fact is disruptive for everyone involved, from your engineering team to your merchants. Getting these answers early on is far less costly than discovering the limitations later.

Asking the Right Questions Upfront

None of these five questions guarantee a perfect partnership. What they do is surface the information that actually matters, long before a contract is signed and long before the consequences of a poor fit start showing up in support tickets or merchant complaints.

ISVs who take the time to evaluate a payments partner this carefully can avoid the costly switches and merchant friction that come from a rushed decision. In an industry where payments touch nearly every part of the merchant relationship, that upfront diligence pays for itself many times over.