Alchemer (SurveyGizmo).

1 · Pass the Samply IDs into the survey

A Hidden Value Action on the first page populated with the URL-variable merge code [url("msg")] (lowercase) names and stores the parameter for export.

1. On the FIRST page, Add New → Action → Hidden Value; give it a title like "Samply Message ID".
2. In the value, click "Select a Merge Code", search "URL variable", insert it and set the name to your parameter, e.g. [url("msg")]. The merge-code name MUST be lowercase.
3. Repeat for the Samply ID and participant code as needed.
4. When exporting, enable "Include URL Variables" so the values appear.

2 · Register completion

A URL Redirect Action on the final page; the URL field is merge-code compatible, so the path carries [url("msg")].

1. Capture the message id first (Hidden Value with [url("msg")]).
2. On the LAST page, Add New → Action → URL Redirect.
3. In the protocol dropdown choose https://, and in the URL field put host+path WITHOUT the protocol: samply.uni-konstanz.de/studies/<study-code>/done/[url("msg")].
4. Do NOT use "Fields To Pass" (that appends ?name=value query strings rather than building the /done/<id> path). Save and test.

Or register completion silently with a POST

The redirect above navigates the participant's browser to Samply. The same completion can instead be registered server-to-server with an HTTP POST to /studies/<study-code>/done/<message-id> — no request body and no authentication (the message id in the path is the shared secret). Samply replies 200 on success or 400if the id matches no response, and it records the completion and cancels that send's pending reminders exactly like the redirect — just without redirecting. Whether Alchemer (SurveyGizmo) can issue that POST itself varies:

1. Requires an enterprise Alchemer plan — the Webhook action is enterprise-only; otherwise use the URL Redirect above.
2. On the final / Thank-You page, click Action → Webhook.
3. Set Method to POST (Samply ignores the body) and set it to run "when the page is displayed" so it fires on completion.
4. In the URL field, insert the [url("msg")] merge code into the path via "Select a Merge Code": https://samply.uni-konstanz.de/studies/<study-code>/done/[url("msg")]
5. Enable Asynchronous Connect, save, and run a live test — critically confirm the merge code resolved inside the path (Alchemer only documents merge codes in the query string; if it fails there is no path fallback).

POST sources: https://help.alchemer.com/help/survey-webhook · https://help.alchemer.com/help/url-variables

Full request and response details are in the API reference.

Reserved parameters & gotchas

Do not name a variable source (breaks quotas/logic) or sguid (reserved). The merge-code name inside [url("…")] must be lowercase, though the incoming key is matched case-insensitively.

Things to watch out for

• Alchemer's redirect docs mostly show appending query strings via "Fields To Pass"; the path-style approach relies on the URL field being merge-code compatible — verify the rendered redirect in a test response.
• The merged value must not contain http://; the protocol is set by the dropdown, so put only host+path in the field.

Sources

These steps were verified against the platform's official documentation.

• https://help.alchemer.com/help/url-variables
• https://help.alchemer.com/help/merge-codes
• https://help.alchemer.com/help/redirect-to-a-website