Is custom dev work a scaling shortcut or a roadmap trap?

We agreed to build three bespoke integrations for a high-paying enterprise client to secure our first six-figure contract and extend our runway. At first, it felt like a massive win the cash flow was great, and having a big name on our pitch deck gave us instant credibility with investors.

But six months in, the reality set in. Our dev team spends almost 70% of their bandwidth maintaining custom legacy code, fixing edge-case bugs, and jumping on emergency support calls for this single client. Meanwhile, our core SaaS product has barely moved forward, public feature releases are constantly delayed, and our standard paying users are starting to complain about neglected roadmap promises.

It made me realize that chasing short-term enterprise revenue can quietly hijack your product vision, drain your engineering energy, and turn your scalable SaaS company into an expensive software agency.

Have you ever built custom one-off solutions to close a big deal, and was the immediate cash worth the technical debt and lost momentum?