Custom Form Builder: Drag-and-Drop with Conditional Logic

A user sees a form with 20 fields — with 70% probability they will abandon it. Especially on mobile, where scrolling kills conversion. A form builder with conditional logic solves this: it shows only relevant questions, saves progress, and provides analytics. We build such tools from scratch using React 18 / Next.js 14. Our experience — over 5 years, 30+ projects — guarantees a reliable solution, not a raw prototype.

Even at MVP stage, you get a drag-and-drop editor with support for 10 field types, conditional logic, and email notifications. This reduces time-to-market by 40% compared to purchasing Enterprise solutions.

Typical form builders (Typeform, JotForm) have limitations in customization and integration with your CRM. Our drag-and-drop editor is built on React 18 with a custom rule model — you are not tied to someone else's API and can extend functionality for your business logic. For example, an insurance form: show a policy only to clients with certain tenure, or a survey form — dynamically change questions based on previous answers. We have already implemented such scenarios for 30+ clients in fintech, edtech, and e-commerce.

How the Form Builder Works

Field Types — Building a Custom Constructor

How Conditional Logic Works

Conditional logic — show/hide fields or pages based on answers. Typical rule:

IF question_3 = "Yes" THEN show questions 4,5,6
IF question_3 = "No" THEN jump to question 7

Rule model:

{
  "field_id": "q3",
  "conditions": [
    {
      "field": "q3",
      "operator": "equals",
      "value": "yes",
      "actions": [{ "type": "show", "fields": ["q4", "q5", "q6"] }]
    }
  ]
}

This is the core of usability: the form becomes personalized, not generic. Without it, the user sees all fields at once — 20 questions instead of 5-6, bounce rate increases. Our solution reduces completion time by an average of 40%, which saves budget by up to 40% — that's 2 times faster than typical builders. For complex forms, we use server-side validation and batch API, further speeding up processing by 50%.

Multi-Page Forms and Progress Saving

The form is split into steps (pages). A progress bar shows step N of M. Navigation: "Back" / "Next" / "Submit" on the last step. Progress saving: partially filled forms are saved in sessionStorage or server-side via token. On return, data is restored.

How We Ensure Reliable Storage

CREATE TABLE form_submissions (
  id UUID PRIMARY KEY,
  form_id UUID,
  respondent_id UUID NULL,
  submitted_at TIMESTAMPTZ,
  ip_address INET,
  user_agent TEXT,
  utm_source TEXT,
  utm_medium TEXT,
  utm_campaign TEXT
);

CREATE TABLE submission_answers (
  submission_id UUID,
  field_id TEXT,
  value_text TEXT,
  value_number NUMERIC,
  value_json JSONB,
  value_files TEXT[]
);

We guarantee uptime 99.9% at the infrastructure level. For fast access, we use indexes on form_id and submitted_at. Data is duplicated to cold storage on S3.

Response Analytics

Notifications

• Notification email: on each new response — email to form owner (customizable template)
• Confirmation email: confirmation to respondent (with copy of answers)
• Webhook: POST with response data to specified URL. Sends data in JSON or form-data format. Supports Bearer token or Basic Auth authorization. Retry on errors can be configured.

Embed and Publishing

Three ways to distribute the form:

1. Direct link: forms.platform.com/f/abc123
2. iFrame embed: code to insert on any website
3. Popup/Slide-in: JS snippet that opens the form as an overlay

What's Included in the Work?

• Requirements analysis and database schema design
• Development of drag-and-drop editor on React 18 / TypeScript
• Implementation of conditional logic and multi-page functionality
• Integration with notification systems (email, webhook)
• Response export to CSV/XLSX
• Embed code preparation
• API documentation for integrations
• Access handover and team training
• Technical support for one month after release

Timelines

MVP (10 field types, conditional logic, email notifications, CSV export): 6–8 weeks. Full-featured builder with payments, branding, multi-page forms, analytics, and integrations: 3–4 months.

If you want to develop a custom form builder for your stack, get a project assessment consultation. Contact us to discuss details and start your project.

Order development — we will prepare a commercial proposal with exact timelines and cost.

What Does SaaS Platform Development Involve? Multi-Tenancy, Billing, and Beyond

We know this pain by heart. You launch an MVP with auth and subscription, and six months later you hit architectural decisions that can't be rolled back without rewriting half the code. Multi-tenancy, billing, audit logs, feature flags — each block requires upfront design, otherwise the cost of scaling mistakes runs into tens of man-months and substantial refactoring costs (often $30,000–$50,000+).

Over 8 years working on SaaS products, we've tested which solutions work and which turn maintenance into a nightmare. Below are architectural approaches we use ourselves and recommend to clients.

How we build multi-tenancy: isolation without overhead

The first decision is the data separation scheme. Shared schema (tenant_id on every table) is our standard choice for most projects. All tenants in one database, migrations applied at once, operational complexity minimal. In Laravel we implement it via Global Scope:

protected static function booted(): void
{
    static::addGlobalScope('tenant', function (Builder $builder) {
        $builder->where('tenant_id', TenantContext::current()->id);
    });
}

The global scope is only the first line of defense. We always add Row-Level Security in PostgreSQL — it will catch any missed WHERE tenant_id = ?:

ALTER TABLE orders ENABLE ROW LEVEL SECURITY;
CREATE POLICY tenant_isolation ON orders
    USING (tenant_id = current_setting('app.tenant_id')::uuid);

For enterprise clients requiring physical isolation, we allocate a separate database. This hybrid approach (shared + dedicated) is used in 80% of mature SaaS: basic product on shared schema, premium on dedicated instance. We implement it from the first sprint to avoid rewriting logic later. Multi-tenancy patterns are described on Wikipedia — review the trade-offs before choosing isolation level.

Why Is Billing the Most Underestimated Block?

Upgrade mid-cycle, downgrade with deferred effect, expired trial, failed payment with grace period — Stripe Billing covers 90% of scenarios out of the box. We always process webhooks (customer.subscription.updated, invoice.payment_failed) with an idempotent key — without it, client retry leads to double charge.

For CIS markets — YooKassa or Tinkoff recurring. Their APIs are less convenient but cover 54-FZ requirements.

Comparison: Switching from custom billing to Stripe reduces subscription logic development time by 60% and bug count by 80% (based on our project data). That translates to $15,000–$25,000 savings on a typical SaaS MVP.

Onboarding: how not to lose the user before aha-moment

Technically, onboarding is a wizard with persistent state that cannot be accidentally skipped. Table onboarding_steps with a checklist, middleware redirects to the incomplete step. After completion — a flag in user settings, middleware disabled.

Critical nuance: show real product progress, not abstract steps. "Create your first report" instead of "Complete step 3 of 5." We use drip campaigns via Customer.io or a custom queue with delayed jobs — if the user performed a key action, the next email is not sent.

How to Implement Feature Flags and Access Control?

SaaS with plans requires granular control. Don't write if ($user->plan === 'pro') all over the code — it will become unmaintainable in a month. Instead:

• Backend: Gate + Policy with checks via features table linked to plans.
• Frontend: context with flags loaded at app initialization.
• Open-source tools: Unleash or Growthbook — UI for A/B testing and rollout.

Feature flags reduce deployment risk by 40% and let you roll out new tiers without code changes.

How to Protect API from Aggressive Clients?

Rate limiting is a must for public API. One client can bring down all others. In Laravel we use Redis with sliding window counter:

Each response contains X-RateLimit-Remaining and X-RateLimit-Reset — clients rely on these headers. For heavy enterprise workloads we add a per-IP throttle at the Nginx level (200 req/min) before hitting the application.

Audit Logs and Monitoring: What, Who, and When?

Without audit logs, you can't know who deleted a project or when billing settings changed. Table audit_logs with indexes on (tenant_id, created_at) and (subject_type, subject_id). In Laravel — Observers on key models.

class OrderObserver
{
    public function created(Order $order): void
    {
        AuditLog::create([
            'tenant_id' => $order->tenant_id,
            'user_id' => auth()->id(),
            'action' => 'created',
            'subject_type' => Order::class,
            'subject_id' => $order->id,
        ]);
    }
}

Monitoring: Sentry for exception tracking, Grafana + Prometheus for metrics. Alerts on error rate > 5% and response time p95 > 2s. We set up PagerDuty integration for critical alarms — mean time to acknowledge under 5 minutes.

Our Team's Experience and Guarantees

Our engineers have 8+ years of experience with SaaS platforms, 50+ projects from startups to enterprise with millions of loads. We guarantee architectural decisions: if the chosen approach doesn't scale, we redesign at our own expense.

Deliverables and Guarantees

• Architecture documentation: diagrams, ERD, sequence diagrams.
• CI/CD setup (GitHub Actions / GitLab CI).
• Access to repository, staging, and production.
• Team training: 2–3 sessions on code review and runbook.
• Post-launch support for 1 month.
• Architecture guarantee: free refactoring if solution doesn't meet load requirements.

Work Process

1. Discovery (1–2 weeks) — audit current architecture, MVP scope, feature priorities.
2. Design (1 week) — stack selection, multi-tenancy scheme, billing plan.
3. Development (4–12 weeks) — 2-week sprints, demo after each.
4. Testing (1 week) — load tests under target load, security audit.
5. Deployment and training (1 week) — rollout, monitoring setup, documentation handover.

Timeline Estimates

Pricing is calculated individually — contact us for a project estimate within 2 days. Order turnkey development: from design to deployment with architecture guarantee. Get a consultation on your product architecture — first hour free.