A novel in-trap decay spectroscopy facility has been developed and constructed for use with TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN). This apparatus consists of an open-access spectroscopy ion-trap, which is surrounded radially with up to seven low-energy planar Si(Li) detectors. The ion-trap environment allows for the detection of low-energy photons by providing backing-free storage of the radioactive ions, while guiding decay particles from the trap center via the strong (up to 6 T) magnetic field. Excellent ion confinement is also facilitated by the use of an intense electron beam which provides storage times of minutes or more without ion loss. These advantages, along with careful monitoring and control, provide a significant increase in sensitivity for the detection of X-rays from the electron-capture process. The design, development, and commissioning of this apparatus are presented and the future of the device and experimental technique are discussed.Keywords: in-trap decay spectroscopy, electron capture, beta-decay of highly-charged ions, X-ray detection, electron-beam ion trap, nuclear matrix elements, double beta decay