SaaS Development · Multi Tenant, Billing, SSO

SaaS platforms built to survive enterprise procurement

Multi tenant architecture, Stripe billing, role based access control, immutable audit logs, SAML/OIDC SSO, usage based metering, and an admin console your customer success team actually uses. We build the unglamorous 30% that decides whether a deal closes.

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RG INSYS designs and builds production SaaS platforms for clients across the UK, US, UAE, and India. We focus on the architecture that decides whether you scale beyond your first ten paying customers, multi tenancy, billing, identity, RBAC, audit, observability, and operational tooling.

What we deliver: A multi tenant SaaS platform with billing, identity, RBAC, audit, admin console, and customer success integrations, deployed on your cloud account with infrastructure as code.
Typical timeline: 8 to 16 weeks for first commercial release. Retained engineering thereafter.
Pricing from: $25,000 fixed price build, or monthly retainer from $5,000 to $7,000.
Stack: Next.js + Node.js / TypeScript, PostgreSQL, Stripe, WorkOS or Auth0, Redis, OpenSearch, AWS (or your preferred cloud).
Compliance-ready for: SOC 2 Type 2, HIPAA, GDPR, PCI DSS. AES-256 at rest, TLS 1.3 in transit, RBAC, immutable audit logs.

What's included

Everything you need, end to end

🏢

Multi tenant architecture

Schema per tenant for regulated workloads, row level isolation for cost sensitive ones. Cross tenant queries explicitly blocked at the data access layer. Tenant lifecycle, provisioning, deprovisioning, archival, soft delete, modelled from day one.

💳

Stripe billing done properly

Plans, seats, metered usage, proration, trials, dunning, invoicing, refunds, and tax via Stripe Tax or Avalara. Webhook driven entitlement updates with replay safe handlers. Self serve checkout for SMB, assisted checkout for enterprise.

🔐

Identity, RBAC, and SSO

Email + password, magic link, SAML 2.0, OIDC, and SCIM 2.0 provisioning via WorkOS, Auth0, or self hosted Keycloak. Hierarchical orgs, teams, and resources. Server enforced permission policies; the UI is just a render of what the backend allows.

📋

Audit logs and admin console

Immutable append only audit log of every mutating action. Internal admin console for customer success: impersonate, refund, change plan, replay webhook, export tenant. Real tools, not a database GUI dressed up.

📈

Usage based metering

Real time event ingestion, aggregation per tenant, reconciliation against Stripe meters at end of day. Soft limits with grace periods, hard caps to protect cost. Customers can see their own usage in app, not just on the invoice.

🤝

Customer success integrations

HubSpot or Salesforce for CRM, Intercom or Plain for support, Slack and email for in app notifications, Snowflake or BigQuery export for analytics teams. We wire it once and the data stays in sync, not just at onboarding.

Our method

How a SaaS build actually unfolds

Architecture week

One to two weeks. Multi tenancy decision, identity choice, billing model, compliance posture, hosting region, observability stack, and a written technical design you can take to your board.

Foundation sprints

Sprints 1 to 3. Tenant model, auth and SSO, RBAC, audit log, billing skeleton. AI scaffolds the boilerplate; senior engineers harden the boundaries that decide whether you pass a security review.

Product surface

Sprints 4 to 7. The actual product features sit on top of the foundation. Because the foundation is right, feature work moves fast and tests cover what matters.

Launch and harden

Sprints 8+. Load tests, on call rota, runbooks, status page, error budgets. A 30 day stabilisation window before retainer mode begins.

Our tech stack for SaaS development

The choices below are the defaults we ship with unless a constraint pushes us elsewhere. We bias hard toward managed services for cross cutting concerns (identity, billing, search) so the team can spend its hours on the product surface, not on rebuilding undifferentiated infrastructure.

Next.js / React Node.js / TypeScript PostgreSQL (multi tenant) Stripe Billing + Tax WorkOS / Auth0 Keycloak (self hosted SSO) Redis OpenSearch / Elastic AWS / GCP / Azure Terraform (IaC) PostHog / Mixpanel Sentry + Datadog

Proof

A representative case study

PropTech · Vertical SaaS UK real estate CRM, multi tenant from day one

A vertical SaaS rebuilt on schema per tenant Postgres, Stripe Billing, and WorkOS SSO in 14 weeks

A UK PropTech platform serving estate agencies had grown to 18 paying customers on a single tenant Rails monolith. RG INSYS rebuilt it as a multi tenant Next.js + Node.js SaaS with schema per tenant Postgres, Stripe Billing with metered listings, WorkOS for SAML SSO, and an internal admin console. The new platform passed a SOC 2 readiness audit within three months of launch.

14 wksBuild to launch

18 → 60+Tenants migrated

SSOEnterprise tier shipped

SOC 2Ready in 3 months

Read full case study →

Pricing

Transparent pricing

From $25,000 build

Or $5,000 to $7,000 per month on a retained engineering model. Stack and team size scale with scope.

Architecture sprint: $3,000 (credited to build)
8 to 16 week build phase: from $25,000
Ongoing retainer: $5,000 to $7,000/month
Dedicated team option: from $2,400/eng/month

Full pricing & engagement models →

Transparent. No hidden fees. Free 48-hour estimate.

FAQ

Common questions

Schema per tenant or row level multi tenancy?

It depends on your customers and your compliance posture. Row level isolation with a tenant_id column is cheaper and scales further; schema per tenant gives stronger isolation and is easier to defend to enterprise procurement. We pick during the architecture phase and document why.

How do you handle billing?

Stripe Billing is the default for most clients. We model the product catalogue, plans, seats, metered usage, proration, trials, dunning, and tax (Stripe Tax or Avalara). Self serve checkout for SMB plans and assisted checkout via the admin console for enterprise plans.

Can the platform support enterprise SSO and SCIM?

Yes. SAML 2.0 and OIDC via WorkOS, Auth0, or self hosted Keycloak. SCIM 2.0 for automated user provisioning from Okta, Azure AD, Google Workspace, and OneLogin. Enterprise SSO is usually a paid plan tier so we wire it into the entitlement system.

How is RBAC structured?

Role based access control with hierarchical organisations, teams, and resources. Most clients end up with 4 to 6 named roles plus optional custom roles. All permissions are policy enforced server side; the UI is just a render of what the backend allows.

What does the audit log capture?

Every mutating action: who, when, what entity, what changed, from where (IP and user agent). Immutable, append only, exportable as CSV or via API. Required for SOC 2 type 2 and HIPAA, and useful for enterprise procurement well before either of those.

How do you handle data isolation for HIPAA or PCI?

For HIPAA we use schema per tenant with PHI encrypted at column level using AWS KMS. For PCI DSS we route card data straight to Stripe and never touch PAN in our infrastructure. Both architectures are compliance ready, you still need policies and an audit; we make the technical part defendable.

Can you migrate us off our existing SaaS codebase?

Yes. Most migrations run incrementally with the old system live as a fallback. We typically replace the monolith piece by piece, ship a new admin console first, then move tenants in cohorts. See the legacy modernization service for the playbook.

What is the typical engagement shape?

Most SaaS engagements start with an 8 to 16 week build phase to ship the first commercial release, then move into a monthly retainer for ongoing feature work. Pricing from $25,000 for the build and from $5,000/month for retained engineering.