coss.comdocs

Create a builder session

POST
/v1/sign/templates/{id}/builder_sessions

A short-lived link to the embedded builder for this template: upload documents, add roles, and drag fields onto pages. Embed it with mountBuilder from coss/sign (from an origin in your Sign settings' allowed_origins) for whoever edits the template.

Authorization

bearerAuth
headerAuthorizationBearer <token>

A secret API key from the dashboard: coss_live_… for production environments, coss_test_… for sandbox environments.

Path Parameters

id*string

The template's id.

Header Parameters

Coss-Version?"2026-10-10"

The API version (a date) to use for this request. Defaults to your organization's version, pinned to the latest one when it first used the API and upgraded from the dashboard. The SDK always sends the version it was built for.

Value in"2026-10-10"

Request Body

application/json
  1. body
expires_in?integer

Seconds until the link expires: default 3600, at most 86400.

Range60 <= value <= 86400

Response Body

The builder session, with its link.

application/json
  1. response
object*"sign_builder_session"
Value in"sign_builder_session"
id*string
template_id*string
url*string

The builder: embed it (from an allowed origin, mountBuilder from coss/sign) for whoever edits the template: they can upload documents, add roles and place fields. Show it only to them.

token*string

The secret part of url, shown only here.

expires_at*string
Formatdate-time
import { Coss } from "coss";const coss = new Coss({  apiKey: process.env.COSS_API_KEY,  baseUrl: "https://api.coss.com",});const { data, error } = await coss.sign.templates.createBuilderSession("stpl_01k7c8m4q2f3e9v6t5r1n0p8yz", {  expires_in: 3600,});
{  "object": "sign_builder_session",  "id": "sbs_01k7c8m4q2f3e9v6t5r1n0p8yz",  "template_id": "stpl_01k7c8m4q2f3e9v6t5r1n0p8yz",  "url": "https://sign.example/b/sbs_01k7c8m4q2f3e9v6t5r1n0p8yz#cossb_…",  "token": "cossb_…",  "expires_at": "2026-10-26T15:04:05.000Z"}