formbricks

First-party Flutter SDK for Formbricks. Connect your Flutter app to a Formbricks workspace, identify users, set attributes, track code actions, and render targeted in-app surveys in a WebView overlay.

Targets iOS and Android.

Install

flutter pub add formbricks

import 'package:formbricks/formbricks.dart';

Quick start

Mount the Formbricks widget once, high in your tree (e.g. wrapping or alongside your app's home). It initializes the SDK on mount and renders any triggered survey in a modal overlay:

import 'package:flutter/material.dart';
import 'package:formbricks/formbricks.dart';

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Stack(
        children: [
          const HomePage(),
          // Initializes the SDK and hosts the survey overlay.
          Formbricks(
            appUrl: 'https://app.formbricks.com',
            workspaceId: 'wsp_...',
          ),
        ],
      ),
    );
  }
}

Then drive the SDK through its static API from anywhere:

// Trigger a code action — shows a matching, eligible survey.
await Formbricks.track('button_clicked');

// Identify the current user and set attributes.
await Formbricks.setUserId('user_123');
await Formbricks.setAttribute('plan', 'pro');
await Formbricks.setAttributes({'plan': 'pro', 'mrr': 99, 'signup_date': DateTime.now()});

// Pick a survey language, then clear identity on sign-out.
await Formbricks.setLanguage('de');
await Formbricks.logout();

All static methods are sequenced through an internal command queue, so calls run in submission order (a setUserId followed by setAttribute can't race). Each returns a Future<Result<void, FormbricksError>>.

Prefer to initialize before any UI mounts? Call Formbricks.setup(...) directly (see below) — the widget still needs to be in the tree to render surveys, but it won't re-run setup (setup is idempotent).

Public API

Method Description
Formbricks(appUrl:, workspaceId:, logLevel:) Host widget — initializes the SDK and renders triggered surveys.
Formbricks.setup({appUrl, workspaceId, logLevel}) Imperative initialization. Idempotent.
Formbricks.track(String name) Fire a code action; shows a matching eligible survey.
Formbricks.setUserId(String userId) Identify the contact. Switching ids resets the prior user's state first.
Formbricks.setAttribute(String key, Object value) Set one attribute (String / num / DateTime).
Formbricks.setAttributes(Map<String, Object>) Set several attributes at once.
Formbricks.setLanguage(String language) Set the survey language.
Formbricks.logout() Reset to an anonymous session.

Attribute keys must be lowercase letters, numbers, and underscores, and start with a letter. DateTime values are sent as UTC ISO-8601 strings; numbers stay numbers. Identity/attribute changes are debounced (~500 ms) and coalesced into a single backend request.

Identification & targeting

  • Anonymous sessions can be shown any survey that isn't gated behind a targeting segment.
  • After setUserId, the backend returns the user's matched segments; segment-targeted surveys are shown only to users in a matching segment.
  • setLanguage without a userId set updates only the local config (no network request) — it takes effect on the next survey shown.

A tracked action only shows a survey that passes eligibility:

  • displayOption — respondMultiple, displayOnce, displayMultiple, displaySome (+ displayLimit).
  • recontactDays — per-survey value, falling back to the workspace setting, measured from the last display.
  • displayPercentage — a per-trigger dice-roll.

The SDK tracks displays and responses locally as they happen, so e.g. a displayOnce survey stops triggering immediately after it has been shown.

Initialization & error handling

Formbricks.setup reports problems through three channels:

try {
  final result = await Formbricks.setup(
    appUrl: 'https://app.formbricks.com',
    workspaceId: 'wsp_...',
  );

  switch (result) {
    case Ok():
    // SDK is ready.
    case Err(:final error):
    // Invalid input, or a sync failure refreshing an existing cached config —
    // error.message explains. SetupCooldownError means a retry is suppressed.
  }
} on FormbricksSetupError {
  // First-setup network/auth failure — the SDK enters a 10-minute cooldown.
}
  • Returns Err for invalid input (missing or non-http(s) appUrl / workspaceId) and for a workspace/user sync failure when refreshing an existing cached config.
  • Throws FormbricksSetupError when the first setup attempt fails on the network/auth. The SDK then enters a 10-minute error cooldown.
  • Returns Err(SetupCooldownError) for any setup call made within that cooldown window — the SDK stays inert (no network call) and error.retryAt says when it will try again.

setup is idempotent (a second successful call is a no-op), runs through the command queue, and installs a lifecycle-aware expiry ticker that refreshes workspace and user state and pauses while the app is backgrounded.

Set logLevel: LogLevel.debug to see the SDK's 🧱 Formbricks - … trace; the default level is error. Logs never contain attribute values or other PII.

Storage & privacy

Config is persisted with shared_preferences under the key formbricks-flutter. This is not encrypted at rest — avoid putting sensitive Personally Identifiable Information (PII) in attribute values. Survey responses are submitted by the embedded WebView directly to your appUrl over HTTPS; the Dart layer never handles response content.

Platform support

iOS + Android only; Flutter Web and desktop are not supported. Surveys render by loading {appUrl}/js/surveys.umd.cjs in a WebView, so that URL must be reachable from the device. Formbricks Cloud and standard self-hosted instances serve this script automatically — no extra setup is needed unless you host behind a restricted network.

Libraries

formbricks
Formbricks Flutter SDK.