Exhibit 3.3

AMENDMENT TO

APPIAN CORPORATION

BY-LAWS

This Amendment (this “Amendment”) to the By-Laws of Appian Corporation, a Delaware corporation (the “Company”), is adopted and approved this 21^st day of February, 2014 by the stockholders of the Company.

WHEREAS, pursuant to Section 6.6 of the By-Laws, the By-Laws may be altered, and new by-laws made, by the vote or action of the stockholders; and

WHEREAS, in connection with the Company’s sale of Series B Convertible Preferred Stock as part of a financing transaction on the date hereof, the Company has agreed to alter the By-Laws.

NOW THEREFORE, the By-Laws are altered as follows:

Section 2.1. Qualifications. The Board of Directors shall consist of nine (9) members.

AMENDMENT TO

APPIAN CORPORATION

BY-LAWS

This Amendment (this “Amendment”) to the By-Laws of Appian Corporation, a Delaware corporation (the “Company’’), is adopted and approved this 7th day of July, 2008 by the Board of Directors of the Company (the “Board’’).

WHEREAS, pursuant to Section 6.6 of the By-Laws, the By-Laws may be altered, and new by-laws made, by the vote or action of the stockholders; and

WHEREAS, in connection with the Company’s sale of Series A Convertible Preferred Stock as part of a financing transaction on the date hereof (the “Financing”), the Company has agreed to make certain alterations to the By-Laws.

NOW THEREFORE, the By-Laws are altered as follows:

Section 2.1. Qualifications. The Board of Directors shall consist of seven (7) members.

At each annual meeting of stockholders, the stockholders shall elect the directors who shall hold office for a term of one year or until their successors are elected and qualified. Any director may resign at any time upon written notice to the corporation. Any vacancies occurring in the Board of Directors for any cause may be filled by a plurality of the votes cast at a meeting of stockholders, and any director(s) so elected shall hold office until the expiration of the term of office of the director whom he has replaced or until his successor is elected and qualified.

Section 2.4. Special Meetings. Special meetings of the Board of Directors may be held at any time or place within or without the State of Delaware whenever called by: (i) the President, (ii) any member of the Board of Directors or (iii) any holder of at least twenty-five percent (25%) of the then-outstanding shares of the Company’s Series A Convertible Preferred Stock.

Section 2.5. Quorum: Vote Required for Action. At all meetings of the Board of Directors the presence of (i) a majority of the whole Board of Directors, and (ii)

three Directors designated by the holders of Common Stock pursuant the Company’s certificate of incorporation, shall constitute a quorum for the transaction of business.

Section 2.9. Telephonic Meeting. Unless restricted by the Certificate of Incorporation, any one or more members of the Board of Directors or any committee thereof may participate in a meeting of the Board of Directors or such committee by means of a conference telephone or similar communications equipment by means of which all persons participating in the meeting can hear each other. Participation by such means shall constitute presence in person at a meeting.

Section 6.6. Amendment of By-Laws. These by-laws may be altered or repealed, new by-laws made, by the Board of Directors, but the stockholders may make additional by-laws any may alter and repeal any by-laws whether adopted by them or otherwise; provided, that in each case, the approval of the holders of a majority of the then-outstanding shares of Series A Convertible Preferred stock is obtained.

2

Exhibit A

BY-LAWS OF APPIAN CORPORATION

ARTICLE I

Stockholders

Section 1.1. Annual Meetings. An annual meeting of stockholders shall be held for the election of the sole director at such date, time and place, either within or without the State of Delaware, as may be designated by resolution of the Board of Directors from time to time. Any other proper business may be transacted at the annual meeting.

Section 1.2. Special Meetings. Special meetings of stockholders for any purpose or purposes may be called at any time by the Board of Directors, but such special meetings may not be called by any other person or persons.

Section 1.3. Notice of Meetings. Whenever stockholders are required or permitted to take any action at a meeting, a written notice of the meeting shall be given that shall state the place, date and hour of the meeting and, in the case of a special meeting, the purpose or purposes for which the meeting is called. Unless otherwise provided by law, the certificate of incorporation or these by-laws, the written notice of any meeting shall be given not less than ten nor more than sixty days before the date of the meeting to each stockholder entitled to vote at such meeting. If mailed, such notice shall be deemed to be given when deposited in the United States mail, postage prepaid, directed to the stockholder at his address as it appears on the records of the corporation.

Section 1.4. Adjournments. Any meeting of stockholders, annual or special, may adjourn from time to time to reconvene at the same or some other place, and notice need not be given of any such adjourned meeting if the time and place thereof are announced at the meeting at which the adjournment is taken. At the adjourned meeting the corporation may transact any business which might have been transacted at the original meeting. If the adjournment is for more than thirty days, or if after the adjournment a new record date is fixed for the adjourned meeting, notice of the adjourned meeting shall be given to each stockholder of record entitled to vote at the meeting.

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Section 1.5. Quorum. Except as otherwise provided by law, the certificate of incorporation or these by-laws, at each meeting of stockholders the presence in person or by proxy of the holders of shares of stock having a majority of the votes which could be cast by the holders of all outstanding shares of stock entitled to vote at the meeting shall be necessary and sufficient to constitute a quorum. In the absence of a quorum, the stockholders so present may, by majority vote, adjourn the meeting from time to time in the manner provided in Section 1.4 of these by-laws until a quorum shall attend. Shares of its own stock belonging to the corporation or to another corporation, if a majority of the shares entitled to vote in the election of directors of such other corporation is held, directly or indirectly, by the corporation, shall neither be entitled to vote nor be counted for quorum purposes; provided, however, that the foregoing shall not limit the right of the corporation to vote stock, including but not limited to its own stock, held by it in a fiduciary capacity.

Section 1.6. Organization. Meetings of stockholders shall be presided over by the sole director, or in his absence by such person who may be designated by the Board of Directors. The Secretary shall act as secretary of the meeting, but in his absence the person presiding over the meeting may appoint any person to act as secretary of the meeting. The secretary of the meeting shall announce at the meeting of stockholders the date and time of the opening and the closing of the polls for each matter upon which the stockholders will vote.

Section 1.7. Voting; Proxies. Except as otherwise provided by the certificate of incorporation, each stockholder entitled to vote at any meeting of stockholders shall be entitled to one vote for each share of stock held by him which has voting power upon the matter in question. Each stockholder entitled to vote at a meeting of stockholders or to express consent or dissent to corporate action in writing without a meeting may authorize another person or persons to act for him by proxy, but no such proxy shall be voted or acted upon after three years from its unless the proxy provides for a longer period. A proxy shall be irrevocable if it states that it

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is irrevocable and if, and only as long as, it is coupled with an interest sufficient in law to support an irrevocable power. A stockholder may revoke any proxy which is not irrevocable by attending the meeting and voting in person or by filing an instrument in writing revoking the proxy or by delivering a proxy in accordance with applicable law bearing a later date to the Secretary of the corporation. Voting at meetings of stockholders need not be by written ballot and, unless otherwise required by law, need not be conducted by inspectors of election unless so determined by the holders of shares of stock having a majority of the votes which could be cast by the holders of all outstanding shares of stock entitled to vote thereon which are present in person or by proxy at such meeting. At all meetings of stockholders for the election of directors a plurality of the votes cast shall be sufficient to elect. All other elections and questions shall, unless otherwise provided by law, the certificate of incorporation or these by-laws, be decided by the vote of the holders of shares of stock having a majority of the votes which could be cast by the holders of all shares of stock outstanding and entitled to vote thereon.

Section 1.8. Fixing Date for Determination of Stockholders of Record. In order that the corporation may determine the stockholders entitled to notice of or to vote at any meeting of stockholders or any adjournment thereof, or to. express consent to corporate action in writing without a meeting, or entitled to receive payment of any dividend or other distribution or allotment of any rights, or entitled to exercise any rights in respect of any change, conversion or exchange of stock or for the purpose of any other lawful action, the Board of Directors may fix a record date, which record date shall not precede the date upon which the resolution fixing the record date is adopted by the Board of Directors and which record date: (1) in the case of determination of stockholders entitled to vote at any meeting of stockholders or adjournment thereof, shall, unless otherwise required by law, not be more than sixty nor less than ten days before the date of such meeting; (2) in the case of determination of stockholders entitled to express consent to corporate action in writing without a meeting, shall not be more than ten days from the date upon which the resolution fixing the record date is adopted by the Board of

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Directors; and (3) in the case of any other action, shall not be more than sixty days prior to such other action. If no record date is fixed: (1) the record date for determining stockholders entitled to notice of or to vote at a meeting of stockholders shall be at the close of business on the day next preceding the day on which notice is given, or, if notice is waived, at the close of business on the day next preceding the day on which the meeting is held; (2) the record date for determining stockholders entitled to express consent to corporate action in writing without a meeting when no prior action of the Board of Directors is required by law, shall be the first date on which a signed written consent setting forth the action taken or proposed to be taken is delivered to the corporation in accordance with applicable law, or, if prior action by the Board of Directors is required by law, shall be at the close of business on the day on which the Board of Directors adopts the resolution taking such prior action; and (3) the record date for determining stockholders for any other purpose shall be at the close of business on the day on which the Board of Directors adopts the resolution relating thereto. A determination of stockholders of record entitled to notice of or to vote at a meeting of stockholders shall apply to any adjournment of the meeting; provided, however, that the Board of Directors may fix a new record date for the adjourned meeting.

Section 1.9. List of Stockholders Entitled to Vote. The Secretary shall prepare and make, at least ten days before every meeting of stockholders, a complete list of the stockholders entitled to vote at the meeting, arranged in alphabetical order, and showing the address of each stockholder and the number of shares registered in the name of each stockholder. Such list shall be open to the examination of any stockholder, for any purpose germane to the meeting, during ordinary business hours, for a period of at least ten days prior to the meeting, either at a place within the city where the meeting is to be held, which place shall be specified in the notice of the meeting, or if not so specified, at the place where the meeting is to be held. The list shall also be produced and kept at the time and place of the meeting during the whole time thereof and may be inspected by any stockholder who is present. Upon the willful neglect or refusal of the director

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to produce such a list at any meeting for the election of directors, that director shall be ineligible for election to any office at such meeting. The stock ledger shall be the only evidence as to who are the stockholders entitled to examine the stock ledger, the list of stockholders or the books of the corporation, or to vote in person or by proxy at any meeting of stockholders.

Section 1.10. Action By Consent of Stockholders. Unless otherwise restricted by the certificate of incorporation, any action required or permitted to be taken at any annual or special meeting of the stockholders may be taken without a meeting, without prior notice and without a vote, if a consent or consents in writing, setting forth the action so taken, shall be signed by the holders of outstanding stock having not less than the minimum number of votes that would be necessary to authorize or take such action at a meeting at which all shares entitled to vote thereon were present and voted and shall be delivered (by hand or by certified or registered mail, return receipt requested) to the corporation by delivery to its registered office in the State of Delaware, its principal place of business, or an officer or agent of the corporation having custody of the book in which proceedings of minutes of stockholders are recorded. Prompt notice of the taking of the corporate action without a meeting by less than unanimous written consent shall be given to those stockholders who have not consented in writing.

Section 1.11. Conduct of Meetings. The Board of Directors of the corporation may adopt by resolution such rules and regulations for the conduct of the meeting of stockholders as it shall deem appropriate. Except to the extent inconsistent with such rules and regulations as adopted by the Board of Directors, the person providing over any meeting of stockholders shall have the right and authority to prescribe such rules, regulations and procedures and to do all such acts as, in the judgment of such person, are appropriate for the proper conduct of the meeting. Such rules,regulations or procedures, whether adopted by the Board of Directors or prescribed by the person presiding over the meeting, may include, without limitation, the following: (i) the establishment of an agenda or order of business for the meeting; (ii) rules and procedures for maintaining order at the meeting and the safety of those present; (iii) limitations on attendance at

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or participation in the meeting to stockholders of record of the corporation, their duly authorized and constituted proxies or such other persons as the chairman of the meeting shall determined; (iv) restrictions on entry to the meeting after the time fixed for the commencement thereof; and (v) limitations on the time allotted to the questions or comments by participants. Unless and to the extent determined by the Board of Directors or the person presiding over the meeting, meetings of stockholders shall not be required to be held in accordance with the rules of parliamentary procedure.

ARTICLE II

Board of Directors

Section 2.1. Qualifications. The Board of Directors shall consist of one member. No director of the corporation need be a stockholder.

Section 2.2. Election; Resignation; Removal; Vacancies. The Board of Directors shall initially consist of the person named as the sole director by the incorporator who shall hold office until the first annual meeting of stockholders or until his successor is elected and qualified. At the first annual meeting of stockholders and at each annual meeting thereafter, the stockholders shall elect the sole director who shall hold office for a term of one year or until his successor is elected and qualified. The director may resign at any time upon written notice to the corporation. Any vacancies occurring in the Board of Directors for any cause may be filled by a plurality of the votes cast at a meeting of stockholders, and the director so elected shall hold office until the expiration of the term of office of the director whom he has replaced or until his successor is elected and qualified.

Section 2.3. Regular Meetings. Regular meetings of the Board of Directors may be held at such places within or without the State of Delaware and at such times as the Board of Director may from time to time determine, and if so determined notices thereof need not be given.

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Section 2.4. Special Meetings. Special meetings of the Board of Directors may be held at any time or place within or without the State of Delaware whenever called by the President, or by any member of the Board of Directors. Notice of a special meeting of the Board of Directors shall be given by the person or persons calling the meeting at least twenty-four hours before the special meeting.

Section 2.5. Quorum: Vote Required for Action. At all meetings of the Board of Directors a majority of the whole Board of Directors shall constitute a quorum for the transaction of business. Except in cases in which the certificate of incorporation or these by-laws otherwise provide, the vote of a. majority of the directors present at a meeting at which a quorum is present shall be the act of the Board of Directors.

Section 2.6. Organization. Meetings of the Board of Directors shall be presided over by the sole director. The Secretary shall act as secretary of the meeting, but in his absence the sole director may appoint any person to act as secretary of the meeting.

Section 2.8. Informal Action by Directors. Unless otherwise restricted by the certificate of incorporation or these by-laws, any action required or permitted to be taken at any meeting of the Board of Directors, may be taken without a meeting if all members of the Board of Directors consent thereto in writing, and the writing or writings are filed with the minutes of proceedings of the Board of Directors.

ARTICLE III

Officers

Section 3.1. Executive Officers; Election; Qualifications; Term of Office; Resignation; Removal; Vacancies. The Board of Directors shall elect a President and Secretary. The Board of Directors may also choose one or more Vice Presidents, one or more Assistant Secretaries, a Treasurer and one or more Assistant Treasurers. Each such officer shall hold office until the first meeting of the Board of Directors after the annual meeting of stockholders next succeeding his

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election and until his successor is elected and qualified or until his earlier resignation or removal. Any officer may resign at any time upon written notice to the corporation. The Board of Directors may remove any officer with or without cause at any time, but such removal shall be without prejudice to the contractual rights of such officer, if any, with the corporation. Any number of offices may be held by the same person. Any vacancy occurring in any office of the corporation by death, resignation, and removal or otherwise may be filled for the unexpired portion of the term by the Board of Directors at any regular or special meeting.

Section 3.2. Powers and Duties of Executive Officers. The officers of the corporation shall have such powers and duties in the management of the corporation as may be prescribed in a resolution by the Board of Directors and, to the extent not so provided, as generally pertain to their respective offices, subject to the control of the Board of Directors. The Board of Directors may require any officer, agent or employee to give security for the faithful performance of his duties.

ARTICLE IV

Stock

Section 4.1. Certificates. Every holder of stock shall be entitled to have a certificate signed by or in the name of the corporation by the sole director, or the President or a Vice President, and by the Treasurer or an Assistant Treasurer, or the Secretary or an Assistant Secretary, of the corporation certifying the number of shares owned by him in the corporation. Any of or all the signatures on the certificate may be a facsimile. In case any officer, transfer agent or registrar who has signed or whose facsimile signature has been placed upon a certificate shall have ceased to be such officer, transfer agent, or registrar before such certificate is issued, it may be issued by the corporation with the same effect as if he were such officer, transfer agent, or registrar at the date of issue.

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Section 4.2. Lost, Stolen or Destroyed Stock Certificates; Issuance of New Certificates. The corporation may issue a new certificate of stock in the place of any certificate theretofore issued by it, alleged to have been lost, stolen or destroyed, and the corporation may require the owner of the lost, stolen or destroyed certificate, or his legal representative, to give the corporation a bond sufficient to indemnify it against any claim that may be made against it on account of the alleged loss, theft or destruction of any such certificate or the issuance of such new certificate.

ARTICLE V

Indemnification

Section 5.1. Right to Indemnification. The corporation shall indemnify and hold harmless, to the fullest extent permitted by applicable law as it presently exists or may hereafter be amended, any person who was or is made or is threatened to be made a party or is otherwise involved in any action, suit or proceeding, whether civil, criminal, administrative or investigative (a “proceeding”) by reason of the fact that he, or a person for whom he is the legal representative, is or was a director or officer of the corporation or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation or of a partnership, joint venture, trust, enterprise or nonprofit entity, including service with respect to employee benefit plans, against all liability and loss suffered and expenses (including attorneys’ fees) reasonably incurred by such person. The corporation shall be required to indemnify a person in connection with a proceeding (or part thereof) initiated by such person only if the proceeding (or part thereof) was authorized by the Board of Directors of the corporation.

Section 5.2. Prepayment of Expenses. The corporation may, in its discretion, pay the expenses (including attorneys’ fees) incurred in defending any proceeding in advance of its final disposition, provided, however, that the payment of expenses incurred by a director or officer in advance of the final disposition of the proceeding shall be made only upon receipt of an undertaking by the director or officer to repay all amounts advanced if it should be ultimately determined that the director or officer is not entitled to be indemnified under this Article or otherwise.

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Section 5.3. Claims. If a claim for indemnification or payment of expenses under this Article is not paid in full within sixty days after a written claim therefor has been received by the corporation, the claimant may file suit to recover the unpaid amount of such claim and, if successful in whole or in part, shall be entitled to be paid the expense of prosecuting such claim. In any such action the corporation shall have the burden of proving that the claimant was not entitled to the requested indemnification or payment of expenses under applicable law.

Section 5.4. Non-Exclusivity of Rights. The rights conferred on any person by this Article V shall not be exclusive of any other rights which such person may have or hereafter acquire under any statute, provision of the certificate of incorporation, these by-laws, agreement, vote of stockholders or disinterested directors or otherwise.

Section 5.5. Other Indemnification. The corporation’s obligation, if any, to indemnify any person who was or is serving at its request as a director, officer, employee or agent of another corporation, partnership, joint venture, trust, enterprise or nonprofit entity shall be reduced by any amount such person may collect as indemnification from such other corporation, partnership, joint venture, trust, enterprise or nonprofit enterprise.

Section 5.6. Amendment or Repeal. Any repeal or modification of the foregoing provisions of this Article V shall not adversely affect any right or protection hereunder of any person in respect of any act or omission occurring prior to the time of such repeal or modification.

ARTICLE VI

Miscellaneous

Section 6.1. Fiscal Year. The fiscal year of the corporation shall be determined by resolution of the Board of Directors.

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Section 6.2. Seal. The corporate seal shall have the name of the corporation inscribed thereon and shall be in such form as may be approved from time to time by the Board of Directors.

Section 6.3. Waiver of Notice of Meetings of Stockholders, Directors and Committees. Any written waiver of notice, signed by the person entitled to notice, whether before or after the time stated therein, shall be deemed equivalent to notice. Attendance of a person at a meeting shall constitute a waiver of notice of such meeting, except when the person attends a meeting for the express purpose of objecting, at the beginning of the meeting, to the transaction of any business because the meeting is not lawfully called or convened. Neither the business to be transacted at nor the purpose of any regular or special meeting of the stockholders, directors, or members of a committee of directors need be specified in any written waiver of notice.

Section 6.4. Interested Directors and Officers. No contract or transaction between the corporation and one or more of its directors or officers, or between the corporation and any other corporation, partnership, association, or other organization in which one or more of its directors or officers are directors or officers, or have a financial interest, shall be void or voidable solely for this reason, or solely because the director or officer is present at or participates in the meeting of the Board of Directors which authorizes the contract or transaction, if: (1) the material facts as to his relationship or interest and as to the contract or transaction are disclosed or are known to the Board of Directors, the Board of Directors in good faith authorizes the contract or transaction by the affirmative vote of the sole director, and the sole director is disinterested; or (2) the material facts as to his relationship or interest and as to the contract or transaction are disclosed or are known to the stockholders entitled to vote thereon, and the contract or transaction is specifically approved in good faith by vote of the stockholders; or (3) the contract or transaction is fair as to the corporation as of the time it is authorized, approved or ratified, by the Board of Directors or the stockholders.

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Section 6.5. Form of Records. Any records maintained by the corporation in the regular course of its business, including its stock ledger, books of account, and minute books, may be kept on or be in the form of punch cards, magnetic tape, photographs, microphotographs, or any other information storage device provided that the records so kept can be converted into clearly legible form within a reasonable time.

Section 6.6. Amendment of By-Laws. These by-laws may be altered or repealed and new by-laws made, by the Board of Directors, but the stockholders may make additional by-laws and may alter and repeal any by-laws whether adopted by them or otherwise.