PLEASE NOTE THE FOLLOWING IN ADDITION TO THE USUAL DISCLAIMERS THAT ACCOMPANY FREE SOFTWARE: THE RELEASE OF THIS LIBRARY IN NO WAY IMPLIES AN ENDORSMENT OF THE PAYMILL PAYMENT SERVICE. BE CAREFUL OUT THERE. CL-PAYMILL provides an interface to the Paymill payment service API. You should definitely read their documentation in order to use their service. Ie, do NOT just rely on what is written here. You use this interface entirely at your own risk, as stated in the licence. Not everything in here is robustly tested. INSTALLING: cl-paymill requires drakma, st-json and cl+ssl (required for paymill access). However, if you use quicklisp, these are automatically installed for you. Put cl-paymill in a place where quicklisp (http://www.quicklisp.org/beta/) can find it, by default ~/quicklisp/local-projects/ Then do: (ql:quickload :cl-paymill) (pml:initialize-paymill "your private test key from paymill") And the package "PAYMILL" (nickname PML) is installed and ready to use. USAGE: PML:INITIALIZE-PAYMILL (KEY) KEY is a string which is your paymill key, or a symbol with its symbol-value setf to your key string. This macro defines the access functions using the provided key. If you called it with a symbol, you can unbind the symbol afterwards, if you want. Until you call this macro with a key, the access functions will not be defined. If you give it an invalid key all usage will result in access unathorized errors. Use your test-key, unless you want to get billed by Paymill. First some examples, then an explanation: To create a new client, without an email or description: (pml:clients :new) To create a new client, with an email: (pml:clients :new :data '(:email "email@example.com")) To update an existing client's email and description: (pml:clients :update :id "client_xyz12345" :data '(:email "firstname.lastname@example.org" :description "a lousy client")) You get the client ID as a return value from (pml:clients :new). See below. All access has this general form: PML:RESOURCE (ACCESS-TYPE &KEY [ID] [DATA]) Where RESOURCE is a generic function, ACCESS-TYPE is a keyword, optional ID is a string, and optional DATA is for all resources *except WEBHOOKS* (see below), a list (SLOT1 VALUE1 SLOT2 VALUE2 ...) where SLOTN can be a string or a keyword and VALUEN is a string. If SLOTN is a keyword, it is converted to a lowercase string before sending the request to paymill. ACCESS-TYPE determines how the resource should be accessed. Most resources have ACCESS-TYPES :new, :retrieve, :list, and :delete. The possible values for SLOTN depend on the resource which is being accessed. As you have seen in the examples, CLIENTS have settable slots "email" and "description". See the Paymill API docs for other possible values of SLOTN. For WEBHOOKS, DATA is a list which looks like '(:EMAIL <string email> ((:EVENT1 :STATUS1) (:EVENT2 :STATUS) ...)) OR '(:URL <string url> ((:EVENT1 :STATUS1) (:EVENT2 :STATUS) ...)). All keywords are converted to downcased strings, and can be replaced by strings in calls to the resource. See the Paymill API docs for WEBHOOKS for possible events and statuses. The return value(s) also depend on ACCESS-TYPE. Accessing a resource with :NEW returns the id of the created object as a first value, and the actual object (well, actually an st-json representation of it) as the second value. :LIST returns a (gasp) list of st-json representations of the objects of that type. <Aside: from now on, I am not going to bother to write 'an st-json representation of ...' You know what I mean.> :DELETE returns the object (an st-json rep ...) in the "data" slot which Paymill returns from the request. In most cases this is :NULL. Deleting a CLIENT or a SUBSCRIPTION returns the deleted object. :RETRIEVE returns the object :REFUND takes a transaction id and refunds the client the given amount. It should return the transaction but I can't remember if it does so - read the Paymill API. I am not using refunds, so ... Errors: If any call to paymill fails to result in a reply with status code 200, an error is signalled. Here are the conditions, exported from PAYMILL package, together with their status code: PAYMILL-BAD-REQUEST 400 PAYMILL-UNAUTHORIZED 401 PAYMILL-TRANSACTION-ERROR 403 PAYMILL-NOT-FOUND 404 PAYMILL-PRECONDITION-FAILED 412 PAYMILL-SERVER-ERROR 500 <= status-code <= 505 PAYMILL-GENERAL-ERROR other-status-code ~= 200 The error will be signalled from the macro which wraps the actual request, so don't think you can install an error handler by a :before method. Sorry. The following resources are currently accessible, all exported from the PAYMILL package: CLIENTS, TRANSACTIONS, REFUNDS, PAYMENTS, SUBSCRIPTIONS, OFFERS, WEBHOOKS Note: You need to look at st-json as well, but it's nice and simple, and easy to use. You might want to build the interface up towards your app. For example: define (new-client &optional ...), (new-payment ...) etc. Thats what I do. The webhooks interface is new, but tests suggest it is working.