Single send e-mail - link not working on Ipad/iphone


We insert a link in several e-mails using the single send transactional e-mail add-on. For some reason, this link is not working on Ipad/Iphone. It does work on all other devices.
Can somebody assist ASAP?


Hi @yannickpels,

The personalization token used to create the link is processed server side, so in theory it shouldn't depend on the device. For this reason, it's likely related to how iOS handles links instead of the Single Send API. How exactly are you structuring the link?


This is the token that we put behind the CTA:
This gets filled out by a webservice with the benefot for this particular contact


Hi @yannickpels,

I understand this is an ongoing issue for you so perhaps we can shed some more light on what is happening. I've taken a look at the email in question and I can see this in the source code:

    <a href="{{custom.starredlink}}" target="_blank">

I understand your using the Single Send API to pass in your own custom properties into the email and that currently there is issues with this value populating. Could I ask you to provide a little bit more insight into how the web service is working ? This is what is responsible for generating these links correct?

Derek is right in what he says - this should be generated on the server side so by the time it renders in the client the link should exist. If it's not present then the next place we need to look is at the web service. Is this happening for all contacts or just for some contacts?

Look forward to your response,


Hi @jcoldrick,
sorry for the late reply. Here is the feedback I received from our client:

This is over thinking the problem: It’s not a web service, it’s just a link by the time HubSpot is involved. All the links are generated before sending the email and passed in as a parameter.

Here are parameters for that particular email:

{"starredlink":""} (Since this a live link, I changed it so it goes to a 403)

Here’s another example:

{"benefitlink":"","clubname":"Aspria Brussels Avenue Louise","memberfirstname":"xxxx","memberlastname":"xxxx"}


Hi @yannickpels,

How are you formatting those examples in your request? The single send API accepts requests in the following format:

    "emailId": 2853049635,
    "message": {
        "to": "",
        "cc": [""],
        "bcc": [""]
    "contactProperties": [
            "name": "first_name",
            "value": "John"
    "customProperties": [
            "name": "item_1",
            "value": "something they bought"

Where each custom property is represented by an object with name and value fields. It looks from your example that you're using the property's name as the key; that won't properly populate the custom properties, which might be the issue.


Hi Derek,
We are sure that we formatted everything correct. Especially because everything is working as expected on windows e.g.
The problem only occurs on iphone/ipad


@Derek_Gervais any ideas on the above comment?


Hi @yannickpels,

If you're formatting everything correctly in your request to the Single Send API, then I'm at a loss for what might be happening. It's likely some platform-specific rendering issue, but because the custom tokens are completely rendered by the time the email reaches an actual iPhone, it's not related to the actual Single Send API. If you can send me a link to that specific email in your HubSpot portal, I can take a closer look to see what might be causing the issue. Also, what devices / version(s) of iOS have you been able to reproduce this on?