# Custom SaaS Development Services | Multi-Tenant from Day One | Alher Tech > We build production-grade SaaS in 8-16 weeks: multi-tenant Postgres, Stripe billing, audit logs and SSO. React + Node + AWS. Live demo in week one. - Canonical page: https://alhertech.com/en/solutions/saas-development/ - Site: Alher Tech (custom software, AI agents and SEO engineering, https://alhertech.com/) - Contact: https://alhertech.com/en/contact/ --- Production-grade SaaS in 8-16 weeks: multi-tenant Postgres, Stripe billing and audit logs from day one, not bolted on after the first enterprise deal. ## What SaaS Delivers - **Multi-Tenancy That Survives Your First Enterprise Deal**: Most SaaS products fail not because of bad ideas but because the technical foundation collapses the moment a real customer asks for SSO, audit logs or per-tenant data isolation. We design those constraints in from week one (schema-per-tenant or row-level-security in Postgres, Stripe customer per workspace, write-ahead audit trail) so you can sell to mid-market without rewriting the core. - **Billing That Auditors Stop Questioning**: Stripe Billing wired to your subscription plans, idempotent webhooks, dunning emails, proration on plan changes, tax via Stripe Tax. Every invoice is reproducible from the ledger. No more spreadsheets to reconcile MRR. - **Onboarding Designed Around Activation, Not a Form**: We instrument the activation funnel from day one (sign-up → first workspace → first valuable action). Magic-link auth, sample data, a guided first task, so trial-to-paid conversion is measurable and tunable, not a black box. - **Audit Logs That Pass a SOC 2 Pre-Audit**: Every state change writes an immutable record (actor, action, target, before/after, IP, request ID). Logs ship to S3 with object-lock so even an admin cannot rewrite history. It is the cheapest insurance against your first real security review. - **White-Label and SSO Without a Rewrite**: Custom domains per tenant via wildcard TLS, theming tokens scoped to workspace, SAML/OIDC via WorkOS or Auth0 when an enterprise asks. We build the seams in from the start so a six-figure deal does not block on six months of refactor. - **Churn Analytics That Tie Back to Product Usage**: Event tracking for the actions that predict retention, weekly cohort dashboards, in-app surveys triggered by usage drops. You see which features keep customers and which slides into "feature graveyard", before the renewal call. ## How We Build Your SaaS - **Pricing & Tenancy Workshop**: We run a one-day session to lock the pricing model (per-seat, usage, hybrid), the tenant boundary (workspace, org, account) and the data residency constraints. These three decisions shape the whole schema. - **Schema, Auth & Billing Skeleton**: Week one ships a runnable skeleton: Postgres with RLS, magic-link auth, Stripe customer per workspace, a "hello tenant" page deployed to a real domain. From this point every feature is additive. - **Core Feature Sprints**: Two-week sprints, each ending with a demo on the staging tenant your founders use as their daily driver. We push to production behind feature flags so dogfooding starts before public launch. - **Hardening & Observability**: Before paid traffic we add Sentry, structured logs, RED metrics in Grafana, alert rules in Pager and a runbook. Load tests with k6 to know exactly when your single Postgres node will stop being enough. - **Launch & Co-Pilot**: We are on call for the first 60 days post-launch. Weekly retro with your team, hot-fix turnaround under 24 hours, paid feature roadmap kept in the open. Then we hand over with full docs or stay as a fractional product team. ## High-performance stack used by global leaders React/Next.js/Angular on the frontend and Java 21 + Spring Boot + PostgreSQL 14 on the backend: the same stack that BBVA, ING, and Netflix use for their security and performance. ## SaaS: FAQ ### How much does a custom SaaS cost to build? A focused B2B SaaS MVP that can take real money lands between €40,000 and €90,000. A more ambitious v1 with multi-region, SSO, an admin back-office and an integration layer typically runs €90,000 to €180,000. We quote a fixed-scope first phase after a free discovery call so the number is not a surprise. ### How long until we have paying customers? For a focused B2B problem we usually have a paying design partner between week 8 and week 12, sometimes earlier if a charter customer is already lined up. The goal of the first phase is not feature parity, it is getting one workspace to renew month two. ### What stack do you default to and why? React or Next.js on the front, Node.js (or Spring Boot when our Java team owns it) on the back, Postgres with RLS as the database, Redis for queues and caches, Stripe for billing, AWS or Hetzner for the infra. The reason is boring on purpose: we want a stack any senior engineer can take over without a six-month onboarding. ### Can you build a usage-based pricing model? Yes. We instrument metered events at the application layer, aggregate them daily into Stripe Billing meter records, and reconcile monthly against your own ledger to catch drift. This is the same pattern used by API products charging per call or per gigabyte. ### What stays with us after launch? You own the code, the AWS account, the database, the Stripe account, the domain and every credential. We commit to monorepo with a runnable README, deploy scripts, an architecture diagram and a 60-minute walkthrough recording per major subsystem. No DRM, no vendor lock-in. ### Do you support SOC 2 or ISO 27001 prep? We bake the controls auditors actually check: encryption at rest, audit trail, RBAC, MFA on all admin paths, dependency scanning, backup tests. We do not stamp the certificate ourselves, but we work alongside Vanta, Drata or your auditor and have shipped products that passed Type I in under six months. ### Can you take over an existing SaaS codebase? Yes, and we do it often. The first two weeks are an audit: we map the schema, run security and dependency scans, document the deploy pipeline and ship a small low-risk improvement so we earn trust before touching the core. Then we agree on a stabilisation backlog before any new feature work. ### Do you work with clients globally? Yes. We work fully remote with clients across Spain, Europe, the US and LATAM. Time zones, video calls and live demos at every milestone.