A method for in vitro transcription of a DNA template into RNA includes providing a mixture containing a buffer substance, ribonucleoside triphosphates (NTPs), one or more magnesium salts in a concentration of from about 2 mM to about 60 mM, the DNA template, and a recombinant RNA polymerase, and incubating the reaction mixture at from about 25° C. to about 40° C. for from about 1 hour to about 12 hours thereby producing the RNA. A method for in vitro transcription includes providing a DNA template and a cap analogue that binds to −1 and/or +1 nucleotides of promoter for in vitro transcription, thus producing more full length mRNAs, allowing for more flexibility on the choice of first mRNA base, and providing +2 position open for custom sequence.