  I present GrayStarServer (GSS), a stellar atmospheric modeling and spectrum
synthesis code of pedagogical accuracy that is accessible in any web browser on
commonplace computational devices and that runs on a time-scale of a few
seconds. The addition of spectrum synthesis annotated with line identifications
extends the functionality and pedagogical applicability of GSS beyond that of
its predecessor, GrayStar3 (GS3). The spectrum synthesis is based on a line
list acquired from the NIST atomic spectra database, and the GSS
post-processing and user interface (UI) client allows the user to inspect the
plain text ASCII version of the line list, as well as to apply macroscopic
broadening. Unlike GS3, GSS carries out the physical modeling on the server
side in Java, and communicates with the JavaScript and HTML client via an
asynchronous HTTP request. I also describe other improvements beyond GS3 such
as more realistic modeling physics and use of the HTML <canvas> element for
higher quality plotting and rendering of results, and include a comparison to
Phoenix modeling. I also present LineListServer, a Java code for converting
custom ASCII line lists in NIST format to the byte data type file format
required by GSS so that users can prepare their own custom line lists. I
propose a standard for marking up and packaging model atmosphere and spectrum
synthesis output for data transmission and storage that will facilitate a
web-based approach to stellar atmospheric modeling and spectrum synthesis. I
describe some pedagogical demonstrations and exercises enabled by easily
accessible, on-demand, responsive spectrum synthesis. GSS may serve as a
research support tool by providing quick spectroscopic reconnaissance. GSS may
be found at www.ap.smu.ca/~ishort/OpenStars/.
