[Responsys logo]

Exhibit 10.8

[Responsys logo]

August 25, 2007

Antonio Casacuberta

Via Email

Dear Antonio:

It gives me great pleasure on behalf of Responsys, Inc. (“The Company”) to offer you employment as CTO and Vice President of Engineering on the following terms:

Change in Control. In the event of a sale or merger of the company (other than in connection with a reincorporation) which results in more than a 50% change of control of the outstanding shares, 25% of all your shares (450,000 shares) will accelerate, if within 12 months following a change of control, there is an Involuntary Termination of your employment. The provisions contained in this section are not exclusive of the provisions and benefits provided elsewhere in this agreement.

The arbitrator’s decision must be written and must include the findings of fact and law that support that decision. The arbitrator’s decision will be final and binding on both parties, except to the extent applicable law allows for judicial review of arbitration awards. The arbitrator may award any remedies that would otherwise be available to parties if they were to bring the dispute in court. The arbitration will be conducted with the National Rules for the Resolution of Employment Disputes of the American Arbitration Association; provided, however that the arbitrator must allow the discovery authorized by the California Arbitration Act or the discovery that the arbitrator deems necessary for the parties to vindicate their respective claims or defenses. The arbitration will take place in San Mateo County or, at your option, the county in which you primarily worked with the Company at the time when the arbitral dispute or claim first arose.

You and the Company will share the cost of the arbitration equally, except that the Company will bear the cost of the arbitrator’s fee and any other type of expense or cost that you would not be required to bear if you were to bring the dispute or claim in court. Both the Company and you will be responsible for their own attorney’s fees, and the arbitrator may not award attorney’s fees unless a statute or contract at issue specifically authorizes such an award.

The foregoing, not withstanding, this arbitration provision does not apply to (a) worker’s compensation or unemployment insurance claims or (b) claims concerning the ownership, validity, infringement, misappropriation, disclosure, misuse or enforceability of any confidential information, patent right, copyright, mask work, trademark, or any other trade secret or intellectual property held or sought by either you or the Company (whether or not arising under the Proprietary Information and Inventions Agreement between you and the Company).

If an arbitrator or court of competent jurisdiction (the “Neutral”) determines that any provision of this arbitration provision is illegal or unenforceable, then the Neutral will modify or replace the language of this arbitration provision with a valid and enforceable provision, but only to the minimum extend necessary to render this arbitration provision legal and enforceable.

Antonio, we hope that you find the foregoing terms acceptable. You may indicate your agreement with these terms and accept this offer by signing and dating a printed copy of this letter agreement and the attached Proprietary Information and Inventions Agreement and returning them to me. This offer, if not accepted, will expire at the close of business on Friday, August 31 2007. As required by law, your employment with the Company is contingent upon your providing legal proof of your identity and authorization to work in the United States. This offer of employment is contingent upon Responsys’ receipt of a satisfactory security clearance based upon the results of a criminal background investigation. Responsys will obtain your written consent to obtain a limited background investigation pursuant to a separate document

I have read and accept this employment offer:

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EMPLOYMENT, CONFIDENTIAL INFORMATION &

INVENTION ASSIGNMENT AGREEMENT

As a condition of my employment with Responsys, Inc., its subsidiaries, affiliates, successors or assigns (together the “Company”), and in consideration of my employment with the Company and my receipt of the compensation now and hereafter paid to me by Company, I, Antonio Casacuberta, agree to the following:

(a) Company Information. I agree at all times during the term of my employment and thereafter, to hold in strictest confidence, and not to use, except for the benefit of the Company, or to disclose to any person, firm or corporation without written authorization of the Board of Directors of the Company, any Confidential Information of the Company. I understand that “Confidential Information” means any Company proprietary information, technical data, trade secrets or know-how, including, but not Limited to, research, product plans, products, services, customer lists and customers (including, but not Limited to, customers of the Company on whom I called or with whom I became acquainted during the term of my employment), markets, software, developments, inventions, processes, formulas, technology, designs, drawings, engineering, hardware configuration information, marketing, finances or other business information disclosed to me by the Company either directly or indirectly in writing, orally or by drawings or observation of parts or equipment. I further understand that Confidential Information does not include any of the foregoing items which has become publicly known and made generally available through no wrongful act of mine or of others who were under confidentiality obligations as to the item or items involved.

(b) Former Employer Information. I agree that I will not, during my employment with the Company, improperly use or disclose any proprietary information or trade secrets of any former or concurrent employer or other person or entity and that I will not bring onto the premises of the Company any unpublished document or proprietary information belonging to any such employer, person or entity unless consented to in writing by such employer, person or entity.

(c) Third Party Information. I recognize that the Company has received and in the future will receive from third parties their confidential or proprietary information subject to a duty on the Company’s part to maintain the confidentiality of such information and to use it only for certain Limited purposes. I agree to hold all such confidential or

proprietary information in the strictest confidence and not to disclose it to any person, firm or corporation or to use it except as necessary in carrying out my work for the Company consistent with the Company’s agreement with such third party.

(a) Inventions Retained and Licensed. I have attached hereto, as Exhibit A, a list describing all inventions, original works of authorship, developments, improvements, and trade secrets which were made by me prior to my employment with the Company (collectively referred to as “Prior Inventions”), which belong to me, which relate to the Company’s proposed business, products or research and development, and which are not assigned to the Company hereunder; or, if no such list is attached, I represent that there are no such Prior Inventions. If in the course of my employment with the Company, I incorporate into a Company product, process or machine a Prior Invention owned by me or in which I have an interest, the Company is hereby granted and shall have a nonexclusive, royalty-free, irrevocable, perpetual, worldwide license to make, have made, modify, use and search Prior Invention as part of or in connection with such product, process or machine.

(b) Assignment of Inventions. I agree that I will promptly make full written disclosure to the Company, will hold in trust for the sole right and benefit of the Company, and hereby assign to the Company, or its designee, all my right, title, and interest in and to (i) any and all inventions, original works of authorship, developments, concepts, improvements or trade secrets, whether or not patentable or registrable under copyright or similar laws, that I may solely or jointly conceive or develop or reduce to practice, or cause to be conceived or developed or reduced to practice, during the period of time I am in the employ of the Company, and (ii) do hereby so assign any and all proprietary information, trade secrets that underlie, are summarized, embodied or described in, the Company’s Business Plan, a copy of which is incorporated herein by reference and made a part hereof, and all copyrights, whether or not registered, therefore, all trade secrets and/or proprietary information and all other intellectual property rights, no matter how described or denominated, described, contained or reflected therein or related thereto that I have conceived, Invented, created or reduced to practice (either prior to the date hereof or at anytime during the term of my employment) in furtherance thereof (collectively referred to as “Inventions”), except as provided in Section 3(f) below. I further acknowledge that all original works of authorship that are made by me (solely or jointly with others) within the scope of and during the period of my employment with the Company and which are protectible by copyright are “works made for hire” as that term is defined in the United States Copyright Act.

(c) Inventions Assigned to the United States. I agree to assign to the United States government all my right, title, and interest in and to any and all Inventions whenever such full title is required to be in the United States by a contract between the Company and the United States or any of its agencies.

(d) Maintenance of Records. I agree to keep and maintain adequate and current written records of all Inventions made by me (solely or jointly with others) during the

term of my employment with the Company. The records will be in the form of notes, sketches, drawings, and any other format that may be specified by the Company. The records will be available to and remain the sole property of the Company at all times.

(e) Patent and Copyright Registrations. I agree to assist the Company, or its designee, at the Company’s expense, in every proper way to secure the Company’s rights in the Inventions and any copyrights, patents, mask work rights or other intellectual property rights relating thereto in any and all countries, including the disclosure to the Company of all pertinent information and data with respect thereto, the execution of all applications, specifications, oaths, assignments and all other instruments which the Company shall deem necessary in order to apply for and obtain such rights and in order to assign and convey to the Company, its successors, assigns, and nominees the sole and exclusive rights, title and interest in and to such inventions, and any copyrights, patents, mask work rights or other intellectual property rights relating thereto. I further agree that my obligation to execute or cause to be executed, when it is in my power to do so, any such instrument or papers shall continue after the termination of this Agreement. If the Company is unable because of my mental or physical incapacity or for any other reason to secure my signature to apply for or to pursue any application for any United States or foreign patents or copyright registrations covering Inventions or original works of authorship assigned to the Company as above, then I hereby irrevocably designate and appoint the Company and its duly authorized officers and agents as my agent and attorney in fact, to act for and in my behalf and stead to execute and file any such applications and to do all other lawfully permitted acts to further the prosecution and issuance of letters patent or copyright registrations thereon with the same legal force and effect as if executed by me.

(f) Exception to Assignments. I understand that the provisions of this Agreement requiring assignment of Inventions to the Company do not apply to any invention which qualifies fully under the provisions of California Labor Code Section 2870 (attached hereto as Exhibit B). I will advise the Company promptly in writing of any inventions that I believe meet the criteria in California Labor Code Section 2870 and not otherwise disclosed on Exhibit A.

(a) Arbitration. Except as provided in Section 10(b) below, I agree that any dispute or controversy arising out of or relating to any interpretation, construction, performance or breach of this Agreement, shall be settled by arbitration to be held in San Mateo County, California, in accordance with the rules then in effect of the American Arbitration Association. The arbitrator may grant injunctions or other relief in such dispute or controversy. The decision of the arbitrator shall be final, conclusive and binding on the parties to the arbitration. Judgment may be entered on the arbitrator’s decision in any court having jurisdiction. The Company and I shall each pay one-half of the costs and expenses of such arbitration, and each of us shall separately pay our counsel fees and expenses.

(b) Equitable Remedies. I agree that it would be impossible or inadequate to measure and calculate the Company’s damages from any breach of the covenants set forth in Sections 2, 3, and 5 herein. Accordingly, I agree that if I breach any of such Sections, the Company will have available, in addition to any other right or remedy available, the right to obtain an injunction from a court of competent jurisdiction restraining such breach or threatened breach and to specific performance of any such provision of this Agreement. I further agree that no bond or other security shall be required in obtaining such equitable relief and I hereby consent to the issuance of such injunction and to the ordering of specific performance.

(a) Governing Law; Consent to Personal Jurisdiction. This Agreement will be governed by the laws of the State of California, without reference to choice of laws or conflict of laws principles. I hereby expressly consent to the personal jurisdiction of the state and federal courts located in California for any lawsuit filed there against me by the Company arising from or relating to this Agreement.

(b) Entire Agreement. This Agreement sets forth the entire agreement and understanding between the Company and me relating to the subject matter herein and merges all prior discussions between us. No modification of or amendment to this Agreement, nor any waiver of any rights under this agreement, will be effective unless in writing signed by the party to be charged. Any subsequent change or changes in my duties, salary or compensation will not affect the validity or scope of this Agreement.

(c) Severability. If an arbitration or court of competent jurisdiction finds any term or clause in this Agreement invalid under the prevailing law, then only that term or clause shall be modified to comply with the law or otherwise omitted from enforcement and all other provisions shall remain enforceable.

(d) Successors and Assigns. This Agreement will be binding upon my heirs, executors, administrators and other legal representatives and will be for the benefit of the Company, its successors, and its assigns.

IN WITNESS WHEREOF, I execute this Agreement as of the date written below.

EXHIBIT A

LIST OF PRIOR INVENTIONS AND ORIGINAL WORKS OF AUTHORSHIP

EXHIBIT B

CALIFORNIA LABOR CODE SECTION 2870

EMPLOYMENT AGREEMENTS; ASSIGNMENT OF RIGHTS

Any provision in an employment agreement which provides that an employee shall assign, or offer to assign, any of his or her rights in an invention to his or her employer shall not apply to an invention that the employee developed entirely on his or her own time without using the employer’s equipment, supplies, facilities, or trade secret information except for those inventions that either:

(1) Relate at the time of conception or reduction to practice of the invention to the employer’s business, or actual or demonstrably anticipated research or development of the employer.

(2) Result from any work performed by the employee for the employer.

(a) To the extent a provision in an employment agreement purports to require an employee to assign an invention otherwise excluded from being required to be assigned under subdivision (a), the provision is against the public policy of this state and is unenforceable.”

EXHIBIT C

RESPONSYS, INC. TERMINATION CERTIFICATION

This is to certify that I do not have in my possession, nor have I failed to return, any devices, records, data, notes, reports, proposals, lists, correspondence, specifications, drawings, blueprints, sketches, materials, equipment, other documents or property, or reproductions of any aforementioned items belonging to Responsys, Inc., its subsidiaries, affiliates, successors or assigns (together, the “Company”).

I further certify that I have complied with all the terms of the Company’s Employment Confidential Information and Invention Assignment Agreement signed by me, including the reporting of any inventions and original works of authorship (as defined therein), conceived or made by me (solely or jointly with others) covered by that agreement.

I further agree that, in compliance with the Employment, Confidential Information and Invention Assignment Agreement, I will preserve as confidential all trade secrets, confidential knowledge, data or other proprietary information relating to products, processes, know-how, designs, formulas, developmental or experimental work, computer programs, data bases, other original works of authorship, customer lists, business plans, financial information or other subject matter pertaining to any business of the Company or any of its employees, clients, consultants or licensees.

I further agree that for twelve (12) months from this date, I will not solicit, induce, recruit or encourage any of the Company’s employees to leave their employment.

apply throughout my employment, to the extent permitted by law unless I revoke or cancel my consent by sending a signed letter or statement to the Company at any time. This Disclosure and Consent form, in original, fixed, photocopied or electronic form, will be valid for any reports that may be requested by the Company.

Applicant Last Name      Casacuberta          First Antonio              Middle                               

Social Security #                             Date of Birth (for ID purposes only)                              

Drivers License #                             Phone Number                              

Present Address                              

City/State/Zip                                                                                    

Applicant Signature             /s/ Antonio Casacuberta                                                             

CALIFORNIA, MINNESOTA AND OKLAHOMA APPLICANTS ONLY: