Industries

IT solutions for SaaS software vendors

A SaaS vendor sells software it must host, evolve and keep available for all its customers at once. Every technical decision (data isolation, billing, deployments, cloud costs) has a direct effect on margin and on the ability to sign new customers.

Agencei supports SaaS vendors at every stage: designing and building a first product, adding features, industrialising the infrastructure, redesigning an application that has become hard to maintain, or reinforcing an internal team. We work with Next.js, React, Java/Spring Boot, Node.js, PostgreSQL and AWS.

We pay particular attention to the topics specific to SaaS: multi-tenant architecture, subscription management, public API, access security, observability and hosting cost control.

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Industry challenges

Data isolation between customers

Multi-tenancy shares the infrastructure, but every customer must be certain their data is isolated. Choosing between a shared database with row-level security, separate schemas or dedicated databases commits the architecture for a long time.

Subscriptions, billing and free trials

Plans, quotas, trial periods, prorated plan changes, VAT and invoices: SaaS billing is a business domain in its own right that must stay consistent with access rights.

Frequent deployments without downtime

Shipping several times a week without interrupting the service requires reliable CI/CD pipelines, compatible database migrations and progressive deployment strategies.

Enterprise customer requirements

SSO, audit logs, fine-grained roles, security questionnaires, availability commitments: enterprise accounts make these features a condition of signing.

Cloud costs and performance at scale

What works for ten customers may cost too much or collapse at a thousand. Sizing, caching, slow queries and background jobs must be monitored continuously.

Technical debt and velocity

A product launched quickly accumulates shortcuts. Past a certain point, every feature takes longer and incidents multiply.

How we respond

Controlled multi-tenant architecture

Design of the isolation model suited to your market (PostgreSQL row-level security, schemas or dedicated databases), with automated tests that verify tenant separation.

Billing and subscription management

Integration of Stripe or an equivalent provider behind a clean abstraction, synchronisation of access rights and handling of edge cases (failed payments, plan changes, refunds).

CI/CD and zero-downtime deployments

GitHub Actions or GitLab CI pipelines, infrastructure described in Terraform, blue/green or progressive deployments, backward-compatible database migrations.

Enterprise features

SAML/OpenID Connect SSO, roles and permissions, audit logs, documented public API and webhooks, to meet enterprise account requirements.

Observability and cost control

Centralised metrics, traces and logs, useful alerts, AWS cost dashboards per component and regular optimisation.

Progressive redesign

When the existing application slows the team down, we redesign it module by module, without a full rewrite or service interruption.

Typical projects

Designing and building a B2B SaaS from scratch
Migrating a single-customer application to a multi-tenant architecture
Integrating subscription billing with Stripe
Rolling out SSO and audit logs for enterprise customers
Industrialising the AWS infrastructure with Terraform and CI/CD
Designing a public API and webhooks for partner integrations
Progressive redesign of a front end in React or Next.js
Optimising cloud costs and performance of a growing SaaS

Frequently asked questions

Shared database, separate schemas or one database per customer: which to choose?

A shared database with row-level security is the simplest to operate and suits most SaaS products. Dedicated schemas or databases are justified for customers demanding strong isolation or with very different volumes. We choose with you based on your market and contractual commitments.

Can you take over a SaaS built by another team?

Yes. We first run a technical audit (code, infrastructure, security, costs) and propose a takeover plan. The redesign then proceeds progressively so the service is never interrupted.

How do you deploy without interrupting the service?

By combining database migrations compatible with both versions, blue/green or progressive deployment and automatic post-deployment checks. Rolling back must be as simple as deploying.

How long does it typically take to launch a first SaaS product?

It depends on the functional scope, the integrations and how mature your specification is. A first product usable by pilot customers generally takes several months; we split the project into regularly delivered versions.

Can you reinforce our internal team?

Yes. We step in on a specific workstream (infrastructure, billing, API, security) or on an ongoing basis, using your tools and joining your rituals.

Tell us about your project

Describe your need in a few lines: we come back to you with a first analysis and the next steps.

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