Exhibit 5.1

CLEARY GOTTLIEB STEEN & HAMILTON LLP   One Liberty Plaza New York, NY 10006-1470 T: +1212 225 2000 F: +1212 225 3999   clearygottlieb.com   WASHINGTON, D.C. • PARIS • BRUSSELS • LONDON • MOSCOW   FRANKFURT • COLOGNE • ROME • MILAN • HONG KONG   BEIJING • BUENOS AIRES • SÃO PAULO • ABU DHABI • SEOUL   D: +1 (212) 225-2494 sflow@cgsh.com THOMAS J. MOLONEY RICHARD S. LINCER JAMES A. DUNCAN STEVEN M. LOEB CRAIG B. BROD NICOLAS GRABAR CHRISTOPHER E. AUSTIN HOWARD S. ZELBO DAVID E. BRODSKY ARTHUR H. KOHN RICHARD J. COOPER JEFFREY S. LEWIS PAUL J. SHIM STEVEN L. WILNER ANDRES DE LA CRUZ DAVID C. LOPEZ MICHAEL A. GERSTENZANG LEV L. DASSIN NEIL Q. WHORISKEY JORGE U. JUANTORENA MICHAEL D. WEINBERGER DAVID LEINWAND DIANA L. WOLLMAN JEFFREY A. ROSENTHAL MICHAEL D. DAYAN CARMINE D. BOCCUZZI, JR. JEFFREY D. KARPF KIMBERLY BROWN BLACKLOW ROBERT J. RAYMOND SUNG K. KANG SANDRA L. FLOW FRANCISCO L. CESTERO FRANCESCA L. ODELL WILLIAM L. MCRAE JASON FACTOR JOON H. KIM MARGARET S. PEPONIS LISA M. SCHWEITZER JUAN G. GIRALDEZ DUANE MCLAUGHLIN BREON S. PEACE CHANTAL E. KORDULA BENET J. O’REILLY ADAM E. FLEISHER SEAN A. O'NEAL GLENN P. MCGRORY MATTHEW P. SALERNO MICHAEL J. ALBANO VICTOR L. HOU ROGER A. COOPER AMY R. SHAPIRO JENNIFER KENNEDY PARK ELIZABETH LENAS LUKE A. BAREFOOT JONATHAN S. KOLODNER DANIEL ILAN MEYER H. FEDIDA ADRIAN R. LEIPSIC ELIZABETH VICENS ADAM J. BRENNEMAN ARI D. MACKINNON JAMES E. LANGSTON JARED GERBER COLIN D. LLOYD COREY M. GOODMAN RISHI ZUTSHI JANE VANLARE DAVID H. HERRINGTON KIMBERLY R. SPOERRI AARON J. MEYERS DANIEL C. REYNOLDS ABENA A. MAINOO HUGH C. CONROY, JR. JOSEPH LANZKRON MAURICE R. GINDI KATHERINE R. REAVES RAHUL MUKHI ELANA S. BRONSON MANUEL SILVA KYLE A. HARRIS LINABENSMAN ARON M. ZUCKERMAN     ^{RESIDENT PARTNERS} SANDRA M. ROCKS JUDITH KASSEL PENELOPE L. CHRISTOPHOROU BOAZ S. MORAG MARY E. ALCOCK HEIDE H. ILGENFRITZ KATHLEEN M. EMBERGER AVRAM E. LUFT ANDREW WEAVER HELENA K. GRANNIS JOHN V. HARRISON CAROLINE F. HAYDAY NEIL R. MARKEL KENNETH S. BLAZEJEWSKI LAURA BAGARELLA SHIRLEY M. LO JONATHAN D.W. GIFFORD SUSANNA E. PARKER DAVID W.S. YUDIN RESIDENT COUNSEL LOUISE M. PARENT OF COUNSEL

February 21, 2020

Endurance International Group Holdings, Inc.

10 Corporate Drive, Suite 300

Burlington, Massachusetts 01803

Re: Registration Statement on Form S-3

Ladies and Gentlemen:

We have acted as special counsel to Endurance International Group Holdings, Inc., a Delaware corporation (“Holdings”), EIG Investors Corp., a Delaware corporation and a wholly owned subsidiary of Holdings (the “Company”), and the Guarantors (as defined below) in connection with the preparation and filing with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), of registration statements on Form S-3 (the “Registration Statements”) relating to market-making activities by an affiliate of Holdings in respect of up to $350,000,000 aggregate principal amount of the Company’s 10.875% Senior Notes due 2024 (the “Notes”). The Notes are fully and unconditionally guaranteed by (i) Holdings, Constant Contact, Inc., a Delaware corporation (“Constant Contact”), Domain Name Holding Company, Inc., a Delaware corporation (“Domain Name Holding”), Endurance International Group—West, Inc., a Delaware corporation (“EIG West”), The Endurance International Group, Inc., a Delaware corporation (“EIG”), and P.D.R Solutions (U.S.) LLC, a Delaware limited liability company (“P.D.R Solutions”, and together with Holdings, Constant Contact, Domain Name Holding, EIG West and EIG, the “Delaware Guarantors”); (ii) HostGator.com LLC, a Florida limited liability company (the “Florida Guarantor”); (iii) A Small Orange, LLC, a Georgia limited liability company (the “Georgia Guarantor”); and (iv) Bluehost Inc., a Utah corporation (“Bluehost”), and FastDomain, Inc., a Utah corporation (“FastDomain” and together with Bluehost, the “Utah Guarantors,” and together with the Delaware Guarantors, the Florida Guarantor and the Georgia Guarantor, each a “Guarantor,” and, collectively, the “Guarantors”). The Guarantors and the Company are herein referred to as the “Registrants.” The Notes were issued under an indenture dated as of February 9, 2016 (the “Initial Indenture”) among Holdings, the Company, Domain Name Holding, EIG West, EIG, the Florida Guarantor, the Georgia Guarantor, the Utah Guarantors and Wilmington Trust, National Association, as trustee (the “Trustee”), as supplemented by the First Supplemental Indenture dated as of February 9, 2016, among Constant Contact, CardStar, Inc., a Delaware corporation, SinglePlatform, LLC, a Delaware limited liability company, CardStar Publishing, LLC, a District of Columbia limited liability company and the Trustee (the “First Supplemental Indenture”), as supplemented by the Second Supplemental Indenture dated as of April 25, 2019 among P.D.R Solutions, the Company and the Trustee (the “Second Supplemental Indenture”, and together with the Initial Indenture and First Supplemental Indenture, the “Indenture”). The Indenture includes the guarantees of the Notes by the Guarantors (the “Guarantees”).

Cleary Gottlieb Steen & Hamilton LLP or an affiliated entity has an office in each of the cities listed above.

In arriving at the opinions expressed below, we have reviewed the following documents:

(a) the Registration Statements;

(b) executed copies of the Initial Indenture and the Guarantees set forth therein, including the form of the Notes, the First Supplemental Indenture, and the Second Supplemental Indenture; and

(c) copies of the Notes in global form as executed by the Company and authenticated by the Trustee.

In addition, we have reviewed the originals or copies certified or otherwise identified to our satisfaction of all such other documents, and we have made such investigations of law, as we have deemed appropriate as a basis for the opinions expressed below.

In rendering the opinions expressed below, we have assumed the authenticity of all documents submitted to us as originals and the conformity to the originals of all documents submitted to us as copies. In addition, we have assumed and have not verified the accuracy as to factual matters of each document we have reviewed.

Based on the foregoing, and subject to the further assumptions and qualifications set forth below, it is our opinion that (a) the Notes are the valid, binding and enforceable obligations of the Company, entitled to the benefits of the Indenture, and (b) the Guarantees are the valid, binding and enforceable obligations of the Guarantors, entitled to the benefits of the Indenture.

Insofar as the foregoing opinions relate to the validity, binding effect or enforceability of any agreement or obligation of any of the Registrants, (a) we have assumed that each Registrant and each other party to such agreement or obligation is validly existing, has corporate or limited liability company power to enter into such agreement or obligation and has satisfied or, prior to the issuance of the Notes, will satisfy, those legal requirements that are applicable to it to the extent necessary to make such agreement or obligation enforceable against it (except that no such assumption is made as to any of the Registrants regarding matters of the federal law of the United States of America or the law of the State of New York that in our experience normally would be applicable to general business entities with respect to such agreement or obligation) and (b) such opinions are subject to applicable bankruptcy, insolvency and similar laws affecting creditors’ rights generally and to general principles of equity.

We note that the waiver of defenses contained in Section 10.01 of the Indenture may be ineffective to the extent that any such defense involves a matter of public policy in the State of New York.

The foregoing opinions are limited to the federal law of the United States of America and the law of the State of New York.

We hereby consent to the use of our name in the prospectus constituting a part of the Registration Statements under the heading “Legal Matters” and to the use of this opinion letter as a part (Exhibit 5.1) of the Registration Statements. In giving this consent, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission thereunder. The opinions expressed herein are rendered on and as of the date hereof, and we assume no obligation to advise you or any other person, or to make any investigations, as to any legal developments or factual matters arising subsequent to the date hereof that might affect the opinions expressed herein.

Very truly yours,
CLEARY GOTTLIEB STEEN & HAMILTON LLP
By:	/s/ Sandra L. Flow
	Sandra L. Flow, a Partner