BTRS (BTRS) SC 13D BTRS / Bain Capital Venture Fund 2012 ownership change

Exhibit A

AGREEMENT REGARDING THE JOINT FILING OF

SCHEDULE 13D

The undersigned being duly authorized thereunto, hereby execute this agreement as an exhibit to this Schedule 13D to evidence the agreement of the below-named parties, in accordance with the rules promulgated pursuant to the Securities Exchange Act of 1934, as amended, to file this Schedule 13D (including amendments thereto) jointly on behalf of each such party.

Dated: January 22, 2021	Bain Capital Venture Fund 2012, L.P.
	By:	Bain Capital Venture Partners 2012, L.P., its general partner
	By:	Bain Capital Venture Investors, LLC its general partner
	By:	/s/ Enrique T. Salem
		Name: Enrique T. Salem
		Title: Managing Director
	BCIP Venture Associates
	By:	Boylston Coinvestors, LLC its managing partner
	By:	/s/ Enrique T. Salem
		Name: Enrique T. Salem
		Title: Authorized Signatory
	BCIP Venture Associates—B
	By:	Boylston Coinvestors, LLC its managing partner
	By:	/s/ Enrique T. Salem
		Name: Enrique T. Salem
		Title: Authorized Signatory