Prefill parameters and field IDs

Every field has an ID that does not change when you rename the field or move it. It is usually a UUID such as 3f6c2a1e-8b4d-4c2f-9a71-1d2e3f4a5b6c. Four places show it:

• The form's אינטגרציות tab, under אוטומציה ו-API: every field that holds an answer, with its מזהה השדה, a ready קישור עם ערכים ממולאים built from your own fields, and a ready signing request.
• In the editor, a field's settings: מזהה שדה ואינטגרציות, with העתקת מזהה שדה.
• The שיתוף tab's מילוי מראש ב-URL, which builds a link from values you type.
• By API: GET /external/forms/{form}/fields lists each field's id, name and type. See Automation endpoints.

Layout blocks such as headings, text and page breaks have IDs too, but they hold no answer and cannot be prefilled.

https://formy.co.il/forms/service-agreement?3f6c2a1e-8b4d-4c2f-9a71-1d2e3f4a5b6c=Dana+Cohen&8a1d4e2b-5c3f-4a6e-b7d8-9e0f1a2b3c4d=Package+2&c4b3a2d1-6e5f-4d7c-8b9a-0f1e2d3c4b5a=13000&5e6f7a8b-9c0d-4e1f-a2b3-c4d5e6f7a8b9=C-1042

Encode values as any URL query does: build the link with your language's URL library rather than by hand, so spaces, Hebrew and & survive.

const url = new URL('https://formy.co.il/forms/service-agreement')
url.searchParams.set('3f6c2a1e-8b4d-4c2f-9a71-1d2e3f4a5b6c', 'דנה כהן')   // text
url.searchParams.set('c4b3a2d1-6e5f-4d7c-8b9a-0f1e2d3c4b5a', '13000')     // number
url.searchParams.append('9d8c7b6a-5f4e-4d3c-8b2a-1f0e9d8c7b6a[]', 'Email') // multi-select
url.searchParams.append('9d8c7b6a-5f4e-4d3c-8b2a-1f0e9d8c7b6a[]', 'SMS')
console.log(url.toString())

• A field that is not in the link keeps the value the form gives it: empty, or its default.
• An ID that names no field on the form changes nothing, and Formy does not save it with the response.
• The respondent can change any prefilled value unless the field is locked. See [locked and hidden fields](#locked).

The share tab's link builder and the AI assistant do not put signatures, files, repeating groups, calculated fields or matrices in a link. A calculated field is always worked out from the answers, so a link cannot set it.

A select value that matches no option stays in the field, and the form does not submit until the respondent fixes it, so a mapping error shows up in front of the respondent rather than in a signed contract.

Both states are on every plan. Neither keeps a value secret or proves it came from you: it is in the link, where whoever holds it can read and edit it before opening the form. For a price or terms that must not change, send a signing request, which stores the values on the document before anyone opens it.

When a form opens, Formy fills it from the first of these that applies, in order:

1. An edit link for an existing response: the response's saved answers.
2. A draft saved on this device, when the form saves unfinished answers in the browser and the respondent has one. The link's values are then not applied at all.
3. The link's parameters.
4. Each field's own default value, set in the editor, for fields that are still empty.

So a respondent who opened the form before and left a draft sees their draft, not your new values. Test your links in a private browser window.

Put the parameters in the iframe's src. To fill fields after the page loads, for example from what the visitor typed elsewhere on your page, wait for the SDK's ready event and call setField or setFields with the same IDs and values. See the embed SDK.

<iframe id="service-agreement" style="border:none;width:100%;"
  src="https://formy.co.il/forms/service-agreement?5e6f7a8b-9c0d-4e1f-a2b3-c4d5e6f7a8b9=C-1042"></iframe>
<script src="https://formy.co.il/widgets/formy-sdk.min.js"></script>