I went through similar issues when an employer would not make basic workstation accommodations. Have you consulted with your HR department regarding OSHA? OSHA and HR should be your friend in this case. Before that, though, step one is making sure your task chair is set up correctly. This means feet flat on floor, knees roughly 90 degrees, sitting straight, etc. Then, if by some miracle, your desk height plus keyboard height is such that you are still able to maintain good arm position, you are in good shape. You should never have the chair raised up so high that your feet are not supported. Conversely, you don't want the chair too low, either. Otherwise, your only non-out-of-pocket option, other than discussing adjustable keyboard trays in the context of workplace ergonomics with HR, is to put the keyboard on your lap, being careful to keep good arm posture. As an alternative to having an OSHA-related discussion with HR, if your company is large enough to have an environmental health & safety office or similar, you could always request an "official" workstation ergonomics evaluation, which is another way to convince a resistant manager to provide you with a keyboard tray. A keyboard tray should not be a big deal for most companies as they are fairly inexpensive in relation to other solutions. If anything more exotic than a tray is required, you may be stuck with out-of-pocket. I have occasionally had to provide my own ergonomic keyboards and task chairs out-of-pocket as the "solutions" offered by various employers have been marginal at best. Worst case, you can always buy an adjustable tray on Amazon for under $100 and mount it yourself.