01
Greenfield SaaS platform
0→1 build for product-led or sales-led SaaS. Multi-tenancy strategy, billing integration (Stripe / Lago / Metronome), SSO, audit logs, observability, designed in from architecture.
Custom Software · FORGE
SaaS Development.
Production multi-tenant SaaS platforms: multi-tenancy strategy, billing, identity, onboarding, scale. Engineered against the architectural decisions that decide whether the product survives Series B due diligence and the regulatory frame enterprise customers actually require.
- Practice
- Custom Software
- Department
- FORGE
The problem
Most SaaS platforms start single-tenant and pay for it through every customer migration after.
The pattern across SaaS engagements we audit: a v1 that shipped fast on a single-tenant Rails or Express monolith; first enterprise customer arrives and demands SSO, audit logs, custom subdomain, data residency; engineering pulls a quarter to retrofit; second enterprise customer arrives and wants something else; the codebase fragments. The architectural decisions that determine multi-tenancy, billing scope, and identity surface are typically made in week two and revisited every six months for the next three years.
Prosigns ships SaaS platforms with multi-tenancy strategy as primary scope from day one. Pooled vs siloed vs bridge tenancy decided up front against your roadmap. Billing model (usage / seat / hybrid) integrated with metering and revenue recognition. Identity layer that supports SSO, SCIM, and the audit trail enterprise procurement actually requires. Architecture decisions documented in writing; engineers who scope the build are the engineers who ship it.
Where it ships
5 use cases, in production.
Specific applications we’ve built and operated. Not speculative: every example below is grounded in a real shipped engagement.
- 02
12x
tenant onboarding speed
Single-tenant → multi-tenant migration
Refactor an existing single-tenant codebase to multi-tenant without disrupting customers. Tenant-isolation strategy (pooled / siloed / bridge), data migration, dual-running windows.
- 03
Enterprise-tier features
SSO (OIDC / SAML), SCIM provisioning, audit logs, custom roles, custom subdomain, data residency. The features enterprise procurement asks for in week two of a sales cycle.
- 04
Billing + revenue infrastructure
Usage-metering pipelines, seat-based billing, hybrid models, plan-change semantics, revenue-recognition integration. Built so finance doesn't have to reconcile in spreadsheets.
- 05
Multi-region SaaS
Region-aware architectures for data residency (GDPR, PIPEDA, regional sovereignty). Identity, payments, and compute distribution per regulatory frame.
How we engage
4 phases, named in the SOW.
Each phase has a deliverable, an owner, and an acceptance criterion. Not slogans, operating rules.
- 01
Multi-tenancy in writing
Pooled (shared schema, tenant_id), siloed (DB per tenant), or bridge (shared compute, isolated data): decided on the whiteboard before code. Trade-offs documented; tenancy strategy survives the next decade rather than being relitigated every six months.
- 02
Identity + audit from day one
SSO, SCIM, audit logs, role-based access, designed in, not retrofitted before the first enterprise customer. Identity is the substrate every other enterprise feature inherits.
- 03
Billing as primary architecture
Usage metering, plan-change semantics, billing-event idempotency, revenue-recognition integration, engineered alongside the product, not bolted on. Stripe / Lago / Metronome / Chargebee / custom. Picked by fit.
- 04
Operate to compound
Observability calibrated to tenant-level SLOs. Quarterly architectural review. Feature flags (Statsig / GrowthBook / LaunchDarkly) integrated for progressive delivery. The platform compounds value across customers when the substrate doesn't decay between releases.
Capabilities
What’s in scope.
- Multi-tenancy strategy: pooled / siloed / bridge with documented trade-offs
- Identity: SSO (OIDC / SAML), SCIM, audit logs, role-based access
- Billing: usage metering, seat-based, hybrid, plan-change semantics
- Multi-region architecture for data residency and regulatory frame
- Observability: tenant-aware SLOs, structured logging, distributed tracing
- Feature flags + progressive delivery for production rollouts
- Onboarding flows: self-serve, sales-assist, white-glove enterprise
- Compliance scope: SOC 2, ISO 27001, HIPAA-ready engagements
Stack
Tools we use in production.
- Languages
- TypeScriptPythonGoJavaKotlin
- Frameworks
- Next.jsReactRemixSpringFastAPI.NET
- Databases
- PostgreSQLMySQLMongoDBDynamoDBRedis
- Identity
- Auth0OktaWorkOSMicrosoft Entra IDCustom OIDC
- Billing
- StripeLagoMetronomeChargebeeOrb
- Cloud + ops
- AWSAzureGCPTerraformDatadogStatsig
Selected work
Quantified outcomes, not adjectives.
Common questions
Asked before the first call.
- 01
Pooled, siloed, or bridge tenancy?
Workload-dependent. Pooled (shared schema, tenant_id column) wins for high-volume / low-isolation needs. Siloed (DB per tenant) wins for regulated / sovereignty / very-high-isolation. Bridge (shared compute, isolated data) is the most common choice for enterprise SaaS, gets most of the operational simplicity of pooled with the data isolation of siloed. We document the trade-offs on the whiteboard before code.
- 02
Stripe, Lago, Metronome, which billing platform?
Use case dependent. Stripe wins for the broadest feature set and lowest integration cost. Lago and Metronome win for high-volume usage-based billing where Stripe's metering model doesn't scale. Chargebee wins when subscription-management ergonomics matter. Custom billing makes sense rarely, when the pricing model genuinely doesn't fit any platform. We assess and recommend in writing.
- 03
Can you migrate us from single-tenant to multi-tenant?
Yes: strangler-fig migration with documented rollback. We've migrated production SaaS from single-tenant Rails / Django / Laravel to multi-tenant architectures across 6–14 month engagements. Most cutovers land with under 30 minutes of total per-tenant downtime.
- 04
How do you handle SSO / SCIM for enterprise customers?
OIDC and SAML support designed in from day one. SCIM provisioning for the major IdPs (Okta, Microsoft Entra ID, OneLogin, JumpCloud). WorkOS as a fast path when integration time matters; native implementation when control matters. We tell you which fits.
- 05
What about SOC 2 / HIPAA from the start?
CITADEL co-pilots compliance scope from kickoff for engagements that will need it. SOC 2 Type II evidence pipelines, HIPAA Security Rule controls, ISO 27001 alignment, engineered into the architecture rather than retrofitted before audit. Most engagements ship with first-attempt audit pass.
- 06
What does a SaaS engagement cost?
Discovery + ADR: 4–6 weeks, $50K–$150K. Greenfield SaaS MVP: 5–9 months, $400K–$1.2M. Single-tenant → multi-tenant migration: 6–14 months, $700K–$2.5M. Enterprise-tier feature build (SSO + SCIM + audit + RBAC): 3–5 months, $250K–$700K. Managed Services for ongoing operations: $30K–$150K monthly retainer.
Within Custom Software
Other capabilities in this practice.
Talk to us
Bring a SaaS development problem. We’ll bring a senior engineer.
A senior engineer plus the FORGE department lead joins the first call. No discovery gauntlet, no junior reps.