We report an optically accessible pyrolysis micro-reactor suitable for in situ laser spectroscopicmeasurements. A radiative heating design allows for completely unobstructed views of the micro-reactor along two axes. The maximum temperature demonstrated here is only 1300 K (as opposed to 1700 K for the usual SiC micro-reactor) because of the melting point of fused silica, but alternative transparent materials will allow for higher temperatures.Laser induced fluorescencemeasurements on nitric oxide are presented as a proof of principle for spectroscopic characterization of pyrolysis conditions.