SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No.        )

Filed by the Registrant  ☒                                     Filed by a Party other than the Registrant  ☐

Check the appropriate box:

☐	Preliminary Proxy Statement
☐	Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))
☐	Definitive Proxy Statement
☒	Definitive Additional Materials
☐	Soliciting Material Pursuant to § 240.14a-12

Everbridge, Inc.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement if Other Than the Registrant)

Payment of Filing Fee (Check the appropriate box)

☒	No fee required.
☐	Fee paid previously with preliminary materials.
☐	Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11

+ C 1234567890 000004 ENDORSEMENT_LINE______________ SACKPACK_____________ MR A SAMPLE Online DESIGNATION (IF ANY) ADD 1 Go to www.envisionreports.com/EVBG ADD 2 or scan the QR code — login details are located ADD 3 in the shaded bar below. ADD 4 ADD 5 ADD 6 Votes submitted electronically must be received by May 19, 2022 at 2:00 A.M., Eastern Time. Stockholder Meeting Notice 1234 5678 9012 345 Important Notice Regarding the Availability of Proxy Materials for the Everbridge, Inc. Stockholders’ Meeting to be Held on May 19, 2022 Under Securities and Exchange Commission rules, you are receiving this notice that the proxy materials for the annual stockholders’ meeting are available on the Internet. Follow the instructions below to view the materials and vote online or request a copy. The items to be voted on are on the reverse side. Your vote is important! This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. The 2022 proxy statement and annual report to shareholders are available at www.envisionreports.com/EVBG Easy Online Access — View your proxy materials and vote. Step 1: Go to www.envisionreports.com/EVBG. Step 2: Click on Cast Your Vote or Request Materials. Step 3: Follow the instructions on the screen to log in. Step 4: Make your selections as instructed on each screen for your delivery preferences. Step 5: Vote your shares. When you go online, you can also help the environment by consenting to receive electronic delivery of future materials. Obtaining a Copy of the Proxy Materials – If you want to receive a copy of these documents, you must request one. There is no charge to you for requesting a copy. Please make your request for a copy as instructed on the reverse side on or before May 9, 2022 to facilitate timely delivery. 2NOT COY + 03MGZA

Stockholder Meeting Notice Everbridge, Inc.’s Annual Meeting of Stockholders will be held on May 19, 2022 at 25 Corporate Drive, 4th Floor, Burlington, MA 01803, at 10:00 A.M. Eastern Time. Proposals to be voted on at the meeting are listed below along with the Board of Directors’ recommendations. The Board of Directors recommend a voteFOR all the nominees listed andFOR Proposals 2 and 3. 1. Election of Directors: Richard D’Amore, Alison Dean, Jaime Ellertson, Bruns Grayson, David Henshall, Kent Mathy, Simon Paris and Sharon Rowlands 2. To ratify the selection by the Audit Committee of the Board of Directors of Ernst & Young LLP as the independent registered public accounting firm of the Company for its fiscal year ending December 31, 2022. 3. To approve, on an advisory basis, the compensation of the Company's named executive officers as disclosed in the Proxy Statement. Note: In their discretion, the proxyholders are authorized to vote upon such other business as may properly come before the meeting. PLEASE NOTE – YOU CANNOT VOTE BY RETURNING THIS NOTICE. To vote your shares you must vote online or request a paper copy of the proxy materials to receive a proxy card. If you wish to attend and vote at the meeting, please bring this notice with you. Here’s how to order a copy of the proxy materials and select delivery preferences: Current and future delivery requests can be submitted using the options below. If you request an email copy, you will receive an email with a link to the current meeting materials. PLEASE NOTE: You must use the number in the shaded bar on the reverse side when requesting a copy of the proxy materials. — Internet – Go to www.envisionreports.com/EVBG. Click Cast Your Vote or Request Materials. — Phone – Call us free of charge at 1-866-641-4276. — Email – Send an email to investorvote@computershare.com with “Proxy Materials Everbridge, Inc.” in the subject line. Include your full name and address, plus the number located in the shaded bar on the reverse side, and state that you want a paper copy of the meeting materials. To facilitate timely delivery, all requests for a paper copy of proxy materials must be received by May 9, 2022.