Q:

Docusign REST v2 API : Populating Tab text data when creating an envelope via template

First time that I've used the Docusign API and it seems great.. but am having issues...
I've tried a number of various changes to my XML format and just cannot get any tabs to populate with data via my API call.  I created a simple template & a single Signer, called "Checker".  I added a label to the template called lblTest.  I've verified that the "Checker" is a signer and can see the tabs that I add.  
All that I'm trying to do is pass through a value that I want to display on a single template in an envelope.. that's it.. should be very simple! 
I'm following the code here --> http://iodocs.docusign.com/APIWalkthrough/requestSignatureFromTemplate
The document is being sent, but the tab data is not being populated.  
The XML I'm POSTing to ~/envelopes is as follows
<envelopeDefinition xmlns=\http://www.docusign.com/restapi\> 
                        <status>sent</status> 
                        <emailSubject>DocuSign API - Signature Request from Template</emailSubject> 
                        <templateId><<redacted>></templateId> 
                        <templateRoles> 
                            <templateRole> 
                                <name>Some Fake Person</name> 
                                <email><<redacted>></email> 
                                <roleName>Checker</roleName> 
                                 <tabs> 
                                    <textTabs> 
                                        <textTab> 
                                        <tabLabel>lblTest</tabLabel> 
                                            <value>12345678</value> 
                                        </textTab> 
                                    </textTabs> 
                                </tabs>          
                            </templateRole> 
                        </templateRoles> 
                       </envelopeDefinition>;

I've posted my API call, to show envelope recipients, as suggested in other posts.  
API call result for 
https://demo.docusign.net/restapi/v2/accounts/749390/envelopes/08C591B3-F6A4-4A9B-80DA-F7B542E58FE2/recipients?include_tabs=true&include_extended=false
API Call Result: 1 1 789ccf19-7dea-4e1a-bb50-9d273d128105 false Checker 1 created false 1 1 1 56cbbdfd-4f97-492f-9612-015f5ab19843 42 6 false false lblTest false false false false 8 false 60 false false 11
Thank you -- I've spent way too much time on this and am pulling my hair out in frustration!!! 

A:

Try changing <textTab> to <text> -- like this:
<textTabs> 
    <text> 
        <tabLabel>lblTest</tabLabel> 
        <value>12345678</value> 
    </text> 
</textTabs>

Since you're using XML format with the REST API, this page will be helpful >> https://www.docusign.net/restapi/help -- it lists the format of all API requests and responses, in both JSON and XML.