When Face.com announced it was being acquired by Facebook last month for a reported $80 to $100m, you can be sure that it was happy day for Face.com’s founders, employees and investors.

But it wasn’t necessarily a day worth celebrating for developers relying on Face.com’s facial recognition API. The reason: Face.com had just been acquired by one of tech’s biggest names and as we’ve seen time and time again, that often means big changes ahead.

Face.com CEO Gil Hirsch sought to reassure users of his company’s API, writing:

Now, lots of developers use Face.com technology to power various apps and make wonderful products. We love you guys, and the plan is to continue to support our developer community. If there are new developments you can expect to hear from us here, on the developer blog, and through our developer newsletter.

Love, as most of us have learned the hard way, is a complicated thing, and as much as Hirsch may have loved developers using the Face.com API, after spending a couple of weeks with Facebook, he apparently isn’t in love with them.

Last week, Face.com sent an email to its developers. The email stated:

We’re excited to move forward to work with all our friends at Facebook. Part of this process includes closing down other products and services that we are no longer able to support, and this includes the Face.com developers API.

Not surprisingly, developers weren’t thrilled at the sudden break-up. As detailed by TheNextWeb’s Martin Bryant, many turned to Twitter to voice their displeasure at being dumped by a company that had seemed committed to them less than a month ago. “OH GOD. The face.com API is shutting down!!…what are we gonna do???” one asked. “Face.com shut down their API after the Facebook acquisition, months of work wasted,” another lamented.

But how much sympathy should we have for these developers? The perils of relying on third party APIs are well-established, and while it can be difficult to build certain functionality (like facial recognition) from scratch, many developers are still eager to put all their eggs in other companies’ baskets, apparently unwilling to accept the possibility that a web service here today could be gone tomorrow.

This, of course, doesn’t mean companies like Face.com aren’t deserving of some scorn. When Face.com’s Hirsch wrote, “the plan is to continue to support our developer community,” there’s a decent chance he really wanted to. But Hirsch, a seasoned tech entrepreneur, must have known that Facebook’s modus operandi has not been to keep standalone services running. The chances that Facebook would continue to support an API that helps developers build applications off of the Facebook platform seemed slim to none, which is why I wrote “one has to assume that there’s a decent possibility Facebook will either eventually shutter the Face.com API or neglect it to the point that it becomes a less-than-attractive solution.”

So what are developers to do? Third party APIs are great, and in some instances, they create opportunities that wouldn’t have otherwise existed. But developers should use them strategically to mitigate risk.

For companies that provide APIs, being more honest about their strategic directions would be a big help and may even become a prerequisite for success as developers, jilted by companies like Face.com, think twice about whose APIs they use.