If you're an early-stage startup that's still determining product-market fit, then it's completely fair to eschew tests and accumulate tech debt; you're at a higher risk of running out of runway before you've even proven that your business works.
As soon as you have enough users that an outage poses a significant risk to your business, you need to invest in either refactoring to reduce tech debt, or a rewrite. And you NEED to add tests, and a robust deployment process that tests changes at multiple stages with monitoring on the basics (server speed and memory usage, database error rate, etc).
As soon as you have enough users that an outage poses a significant risk to your business, you need to invest in either refactoring to reduce tech debt, or a rewrite. And you NEED to add tests, and a robust deployment process that tests changes at multiple stages with monitoring on the basics (server speed and memory usage, database error rate, etc).
OKCupid got lucky in this case.