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                                  Exhibit 10.4

                     FIRST AMENDMENT TO 10% PROMISSORY NOTE
                     --------------------------------------

     This First Amendment to 10% Promissory Note (this "First Amendment") is
effective as of December 18, 1999 and is entered into between Webb Interactive
Services, Inc. f/k/a Online System Services, Inc. (the "Company") and Castle
Creek Technology Partners LLC ("Castle Creek").

                                    RECITALS
                                    --------

     A. The Company issued to Castle Creek a 10% Promissory Note dated August
25, 1999 in the principal amount of $5,000,000 (the "Note"). Unless otherwise
defined herein, capitalized terms shall have the meanings ascribed to such terms
in the Note.

     B. The Company has requested that Castle Creek make certain amendments to
the Note and Castle Creek is willing to do so subject to the terms and
conditions of this First Amendment.

                                    AGREEMENT
                                    ---------

     Now, therefore, in consideration of the continued performance by the
Company of its obligations under the Note, and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
Company and Castle Creek hereby agree as follows:

     1. Ratification and Incorporation of Note. Except as expressly modified
under this First Amendment (a) the Company hereby acknowledges, confirms, and
ratifies all of the terms and conditions set forth in, and all of its
obligations under, the Note, and (b) all of the terms and conditions set forth
in the Note are incorporated herein by this reference as if set forth in full
herein. The Company represents that it has no offset, defense, counterclaim,
dispute or disagreement of any kind or nature whatsoever with respect to the
amount owing under the Note.

     2. Amendments to Note.

     (a) The third paragraph of the Note is hereby deleted in its entirety and
the following is substituted therefore:

     At the option of the Holder, from and after the completion of the Company
     Conversion (as defined below), interest accruing after the Company
     Conversion may be paid in notes in the form hereof ("PIK Notes") or in
     shares of the Company's Common Stock, no par value (the "Common Stock").
     Interest accruing prior to the Company Conversion shall be paid in cash. If
     the Holder determines to receive interest in shares of Common Stock or
     cash, it shall notify
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     the Company at least three business days in advance of the applicable
     Interest Payment Date, otherwise the interest shall be paid in PIK Notes.
     The principal amount of PIK Notes to be issued as interest shall be equal
     to the dollar amount of interest due at the time of payment. The number of
     shares of Common Stock issued as interest shall be the number determined by
     dividing the dollar amount of interest due by the greater of (i) an amount
     equal to the average of the Closing Bid Prices (as defined herein) of the
     Common Stock for the ten (10) business days prior to the date interest is
     so paid or (ii) $8.00.

Notwithstanding the foregoing, any terms that are defined in the third paragraph
of the Note prior to the date of this First Amendment that are used elsewhere in
the Note from and after the date of this First Amendment but not otherwise
defined in the Note shall continue to have the meanings ascribed to such terms
after the date of this First Amendment.

     (b) The first paragraph of Section 1.2(a) is hereby deleted in its entirety
and the following is substituted therefor:

     The Company shall have the right ("Prepayment at Company's Election") to
     prepay, subject to the limitations herein contained, all or any portion of
     the then outstanding Notes (other than Notes which are the subject of a
     Notice of Conversion (as herein defined) delivered prior to the delivery
     date of prepayment) for the Optional Prepayment Amount if, at any time
     after August 25, 2000, the Closing Bid Prices of the Common Stock is
     greater than or equal to two hundred percent (200%) of the Conversion Price
     then in effect for each of the twenty (20) consecutive trading days
     immediately preceding the date of delivery to the Holders of the Optional
     Prepayment Notice in accordance with the prepayment procedures set forth in
     this Article I (the "200% Election"). Any Prepayment at Company's Election
     pursuant to this Section 1.2 shall be made ratably among Holders in
     proportion to the principal amount of Notes then outstanding. Holders may
     convert all or any part of their Notes selected for prepayment hereunder
     into Common Stock at the Conversion Price by delivering a Notice of
     Conversion to the Company at any time prior to the Effective Time of
     Prepayment (as defined herein). The Optional Prepayment Amount is 115% of
     the principal plus accrued and unpaid interest of the Notes being prepaid.

Notwithstanding the foregoing, any terms that are defined in Section 1.2 of the
Note prior to the date of this First Amendment that are used elsewhere in the
Note from and after the date of this First Amendment but not otherwise defined
in the Note shall continue to have the meanings ascribed to such terms after the
date of this First Amendment.

     (c) The definition of "Conversion Amount" in Section 2.1 is hereby deleted
in its entirety and the following is substituted therefore:

     "Conversion Amount" means (i) the portion of the principal amount of this
     Note elected by Holder to be converted (the "Selected Amount"), which
     amount may
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     be all or any portion of the principal amount of this Note plus (ii) an
     amount equal to the product of (A) N divided by 365 times (B) .10 times (C)
     the Selected Amount.

     (d) The definition of "Conversion Price" in Section 2.1 is hereby deleted
in its entirety and the following is substituted therefore:

     "Conversion Price" means (i) with respect to any Conversion Date prior to
     March 22, 2000, the Fixed Conversion Price, and (ii) with respect to any
     Conversion Date on or after March 22, 2000, the lower of the Fixed
     Conversion Price and the Variable Conversion Price; provided, however, upon
     consummation prior to March 22, 2000 of an equity or equity-like financing
     raising proceeds for the Company of not less than $10 million in which
     Castle Creek Technology Partners LLC has the right to elect to invest not
     less than $5 million on terms no less favorable than are offered to any
     other investor in the financing pursuant to its right pursuant to Section
     4.5(b) of the Securities Purchase Agreement (the "Permanent Financing"),
     then the Conversion Price thereafter means the Fixed Conversion Price. The
     Conversion Price is subject to adjustments as provided herein.

     (e) The definition of "Fixed Conversion Price" in Section 2.1 is hereby
deleted in its entirety and the following is substituted therefor:

     "Fixed Conversion Price" means (i) prior to September 30, 2000, $10.07 and
     (ii) on and after September 30, 2000, if the Permanent Financing is
     consummated, the lower of (A) $10.07, and (B) the greater of (x) the
     average of the Closing Bid Prices for the 20 consecutive trading days
     ending on September 29, 2000 and (y) $8.00 (adjusted for any stock split,
     stock dividend, combination, reclassification or other similar events). The
     Fixed Conversion Price is subject to adjustment as provided herein.

     (f) Section 3.1 is hereby deleted in its entirety and the following is
substituted therefor:

     Conversion at the Option of the Holder. Subject to the limitations on
     conversions contained in Section 3.7 hereof, the Holder may, at any time
     after the Closing Date and from time to time, convert (an "Optional
     Conversion") a Conversion Amount into a number of fully paid and
     nonassessable shares of Common Stock equal to the number determined by
     dividing such Conversion Amount by the Conversion Price.

     (g) The following new Section 3.10 is inserted immediately following
Section 3.9:

     Section 3.10 Company Conversion Option.
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          (a) If the average of the closing trade prices for the Common Stock
     (as reported by Bloomberg Financial Markets) for the 15 consecutive trading
     days commencing on the day after the Registration Statement is declared
     effective (the "Conversion Option Period"), is greater than or equal to
     $12.50 (adjusted for any stock split, stock dividend, combination,
     reclassification or other similar events), then the Company may require the
     Holder to convert up to $2,500,000 of principal amount of this Note in
     accordance with this Article III (a "Company Conversion"). The Company
     Conversion shall be made ratably among Holders in proportion to the
     principal amount of Notes.

          (b) The Company may effect a Company Conversion by delivery of written
     notice to such effect to the Holders (a "Company Conversion Notice") on or
     before the 10th day following the last day of the Conversion Option Period.
     The Company may not deliver a Company Conversion Notice or effect a Company
     Conversion unless (a) the Registration Statement is and has been effective
     and available for use by the Holders for the resale of all shares of Common
     Stock issuable hereunder and pursuant to the Warrants during and since the
     Conversion Option Period, (b) the shares of Common Stock issuable hereunder
     and pursuant to the Warrants are listed for trading on Nasdaq, Nasdaq NMS
     or NYSE and have been reserved for issuance in accordance with the Reserved
     Amount requirement of Section 4.1 hereof, (c) no Event of Default has
     occurred or is continuing.

     (h) Section 8.10 is hereby deleted in its entirety and the following is
substituted therefor:

     Key Officer and Director Transfers. If any Key Officer (as defined below)
     or director (in each case, or any member of his/her family or any trust or
     other entity for the benefit of any member of his/her family), during the
     period beginning on the Closing Date and ending on the date that is six
     months after the registration statement required pursuant to Section 2.1 of
     the Registration Rights Agreement is declared effective, and while such
     person is a Key Officer or director, directly or indirectly, offers, sells,
     transfers, assigns, pledges, or otherwise disposes (except by gift to
     family members or charitable organizations) of any shares of Common Stock,
     or any securities directly or indirectly convertible into or exercisable or
     exchangeable for, or warrants, options or rights to purchase or acquire
     shares of Common Stock (all such securities, "Options") or enter into any
     agreement, contract, arrangement or understanding with respect to any such
     offer, sale, transfer, assignment, pledge or other disposition of any
     Common Stock or Options or provides or files any public notice, including
     pursuant to Rule 144 of the Securities Act, of a bona fide intent to
     dispose of a specified amount of Common Stock or Options (an "Executive
     Transfer"), then the Conversion Price shall be reduced by thirty (30)
     percent of that amount calculated pursuant to Article II hereof; provided,
     however, that Key Officers or directors (and all such entities for the
     benefit of any members of his/her family, collectively) may sell, assign,
     pledge or otherwise dispose of up to 20,000 shares in the aggregate prior
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     to December 31, 1999 and during the 6-month period following the effective
     date of the registration statement, a Key Officer or director (and all such
     entities for the benefit of any member of his/her family, collectively) may
     sell, assign, pledge or otherwise dispose of up to the greater of (i) ten
     percent (10%) of his or her total holdings as of the Issue Date determined
     in accordance with Section 13(d) of the Securities Exchange Act of 1934, as
     amended, or (ii) 25,000 shares of Common Stock without triggering the
     adjustments of this Section 8.10. For purposes of this Section 8.10, Key
     Officer shall mean R. Steven Adams, Lindley S. Branson, William R. Cullen,
     Perry Evans, Andre Durand, Gwenael Hagan and Simon Greenman and any person
     who assumes or performs the duties of any other Key Officer.

     3. Warrant. Simultaneous with execution of this First Amendment, the
Company will issue to Castle Creek a five-year warrant (the "Warrant") to
purchase 136,519 shares of common stock in substantially the form of the
warrant, as amended, previously issued to Castle Creek on August 25, 1999 (the
"First Warrant") except as described below. The exercise price of the Warrant
will be equal to $18.506. If the Permanent Financing is consummated, the
exercise price of the Warrant and the First Warrant shall reset (lower only) on
September 30, 2000 to the average of the closing bid prices for the 20
consecutive trading days ending on September 29, 2000. The shares of Common
Stock issuable upon exercise of the Warrant shall be included in the
registration statement for the First Warrant.

     4. Conditions to Effectiveness. This First Amendment shall become effective
on December 18, 1999 (the "Effective Date"), only upon satisfaction of each of
the following conditions:

          (a) receipt by Castle Creek of this First Amendment duly executed by
     the Company; and

          (b) receipt by Castle Creek of the Warrant and the amended First
     Warrant.

     5. Representations and Warranties. In order to induce Castle Creek to enter
into this First Amendment, the Company represents and warrants to Castle Creek
that the following statements are true, correct and complete as of the Effective
Date of this First Amendment:

     (a) Corporate Power and Authority. (i) The Company has the requisite power
and authority to enter into and perform its obligations under this First
Amendment and the Warrant; (ii) the execution, delivery and performance of this
First Amendment and the Warrant by the Company and the consummation by it of the
transactions contemplated hereby and thereby have been duly authorized by the
Company's Board of Directors and no further consent or authorization of the
Company, its Board of Directors or its stockholders is required; and (iii) this
First Amendment and the Warrant constitute
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valid and binding obligations of the Company enforceable against the Company in
accordance with their respective terms.

     (b) No Conflict. The execution, delivery and performance of this First
Amendment and the Warrant by the Company and the consummation by the Company of
the transactions contemplated hereby and thereby will not (i) result in a
violation of the Certificate of Incorporation or the bylaws of the Company; (ii)
conflict with, or constitute a default (or an event which with notice or lapse
of time or both would become a default) under, or give to others any rights
under, or result in termination, amendment, acceleration or cancellation of, any
agreement, indenture or instrument to which the Company or any of its
subsidiaries is a party, or (iii) result in a violation of any law, rule,
regulation, order, judgment or decree applicable to the Company or any of its
subsidiaries or by which any property or assets of the Company or any of its
subsidiaries is bound or affected.

     (c) Governmental Consents. The execution, delivery and performance by the
Company of this First Amendment and the Warrant will not require any
registration with, consent or approval of, or notice to, or other action to,
with or by, any federal, state or other governmental authority or regulatory
body.

     (d) Incorporation of Representations and Warranties from Securities
Purchase Agreement. The representations and warranties contained in Article III
of the Securities Purchase Agreement are correct in all material respects on and
as of the Effective Date as though made on and as of such date, except to the
extent that a particular representation or warranty by its terms expressly
applies only to an earlier date.

     (e) Absence of Event of Default. No event has occurred and is continuing
that would constitute an Event of Default and no event has occurred which with
the passage of time or the giving of notice would constitute an Event of
Default.

     6. Entire Agreement. This First Amendment, together with the Warrant and
the Note and the other documents executed in connection with the Securities
Purchase Agreement (collectively, the "Loan Documents"), is the entire agreement
between the parties hereto with respect to the subject matter hereof. This First
Amendment supersedes all prior and contemporaneous oral and written agreements
and discussions with respect to the subject matter hereof.

     7. Miscellaneous.

     (a) Counterparts. This First Amendment may be executed in identical
counterpart copies, each of which shall be an original, but all of which shall
constitute one and the same agreement; signature pages may be detached from
multiple separate counterparts and attached to a single counterpart so that all
signature pages are physically attached to the same document. Delivery of an
executed counterpart of a signature page to this First Amendment by facsimile
transmission shall be effective as delivery of a manually executed counterpart
thereof.
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     (b) Headings. Section headings used herein are for convenience of reference
only, are not part of this First Amendment, and are not to be taken into
consideration in interpreting this First Amendment.

     (c) Recitals. The recitals set forth at the beginning of this First
Amendment are true and correct, and such recitals are incorporated into and are
a part of this First Amendment.

     (d) Governing Law. This First Amendment shall be governed by, and construed
and enforced in accordance with, the internal laws of the state of New York
applicable to contracts made and performed in such state, without regard to the
principles thereof regarding conflict of laws.

     (e) Effect. Upon the effectiveness of this First Amendment, from and after
the date hereof, each reference in the Note to "this Note," "hereunder,"
"hereof.," or words of like import shall mean and be a reference to the Note as
amended hereby.

     (f) No Novation. Except as expressly provided in this First Amendment, the
execution, delivery and effectiveness of this First Amendment shall not (i)
limit, impair, constitute a waiver of, or otherwise affect any right, power, or
remedy of Castle Creek under the Note or any other Loan Documents, (ii)
constitute a waiver of any provision in the Note and the Loan Documents, or
(iii) alter, modify, amend, or in any way affect any of the terms, conditions,
obligations, covenants, or agreements contained in the Note and the Loan
Documents, all of which are ratified and affirmed in all respects and shall
continue in full force and effect.

     (g) Conflict of Terms. In the event of any inconsistency between the
provision of this First Amendment and any provision of the Note, the terms and
provisions of this First Amendment shall govern and control.

     In witness whereof, this First Amendment has been duly executed and
delivered as of the date first written above.


                                        WEBB INTERACTIVE SERVICES, INC.

                                        By:  /s/ William R. Cullen
                                             -------------------------------
                                        Its: Executive Vice President, CFO
                                             -------------------------------


                                        CASTLE CREEK TECHNOLOGY PARTNERS LLC
                                        By Castle Creek Partners, LLC.

                                        By:  /s/ Richard S. Marks
                                             -------------------------------
                                        Its: Vice President
                                             -------------------------------