Conventional mRNA products typically provide transient protein expression and may require higher or repeated dosing to achieve the desired therapeutic effect. The development of self-amplifying RNA (saRNA) was sparked by the need to address these limitations. With an encoded viral replicase, saRNA amplifies itself intracellularly, allowing robust and prolonged protein expression from substantially lower RNA inputs. To support advances in research and therapeutic development, we established an saRNA platform for the design, production, quality assessment and functional evaluation of our saRNA constructs. Using a firefly luciferase reporter, we demonstrated the generation of high-quality, sequence-verified AU-capped saRNA, containing either unmodified nucleotides or 5-methylcytidine modification, capable of sustained protein expression for up to 96 hours post transfection, outperforming conventional linear mRNA at equivalent RNA outputs. These findings validate the functionality of our saRNA platform and support the expansion of our off-the-shelf portfolio for providing high quality research tools for RNA therapeutic development and vaccine development.