→ AI web application development services
AI web application development services for products that need to ship
We build full-stack AI-powered web applications: AI-native SaaS, customer portals with intelligent workflows, internal copilots embedded where work actually happens. Next.js, TypeScript, Python.
Overview
How we approach this work.
AI web application development services from Resser means full-stack apps where AI is inside the product, not bolted onto the side as a chat widget. The model call is integrated with the database, the authentication, the role model, and the workflow your users already follow.
We have shipped this pattern for healthcare platforms, industrial SaaS, productivity tools, and fintech infrastructure. Each build had the same hard parts: integrating with real data, hitting an eval bar, surviving real traffic, and staying within a cost ceiling.
Most agencies that sell 'AI web apps' ship a prototype that runs in a notebook. We ship a production system with eval in CI, cost telemetry, prompt versioning, and a runbook your on-call engineer can use at 3am.
What we build
Concrete deliverables.
AI-native SaaS products
Brand-new SaaS where AI is the product. Full-stack web app, auth, billing, multi-tenant data, AI features built with eval coverage from day one.
AI features inside an existing web app
Drop a copilot, a summarizer, a generator, or an intelligent search layer into the product you already ship. Integrated with your auth, your database, your audit log.
Internal copilots and AI portals
Web tools that your own team uses internally. Sales copilots, ops copilots, support copilots, internal knowledge portals with RAG.
Customer-facing AI workflows
Multi-step AI flows your end users walk through: intake triage, document review, content generation with human approval, AI-driven onboarding.
Web admin dashboards for AI systems
Operator-facing dashboards for prompt versioning, eval review, cost monitoring, and human-in-the-loop approval queues.
Real-time streaming UIs
Token-by-token streaming, tool calls visualized live, multi-step agent traces shown to the user as they happen. Vercel AI SDK end-to-end.
How we do it
The process, in four phases.
Discovery week (1 week, fixed price)
We talk to your engineers, look at your codebase, sketch the eval set on real examples, and write the spec. Output: technical spec, eval design, cost and timeline model.
Prototype sprint (2-3 weeks)
A working web app slice in your environment, integrated with at least one real data source, with the eval suite live by week 2.
Hardening (2-6 weeks)
Eval in CI, cost telemetry, retry logic, prompt versioning, runbook, and an admin dashboard for your operators.
Launch and handover
Production deploy on your cloud or ours. Your team owns the codebase. We stay on retainer if useful.
Stack
What we build with.
Frontend
Next.js 15, React 19, TypeScript, Tailwind CSS v4, Vercel AI SDK for streaming UIs and tool calls.
Backend
Node.js, Python (FastAPI, Django), Go for high-throughput services. Postgres (Supabase, Neon, RDS) by default; pgvector for retrieval.
AI
Anthropic Claude (Sonnet, Haiku, Opus), OpenAI GPT-4o, open-weights via vLLM. LangGraph for stateful agents. Helicone / LangSmith for observability.
Auth, infra, deploy
Auth.js, Clerk, or custom JWT. AWS, GCP, Azure, Fly, Vercel. CI/CD via GitHub Actions or whatever your team already uses.
Outcomes
What we ship.
Healthcare intake web app: material accuracy lift on the triage classifier, near-instant routing replacing manual handling.
Industrial SaaS portal: field technicians find answers in seconds instead of minutes, every answer cited from the source manual.
B2B SaaS admin: AI-native review dashboard shipped end-to-end, dramatically reducing the manual review queue.
References with names available after a scoping call.
Related services
Other places this work shows up.
FAQ
Frequently asked.
How is this different from adding an AI chatbot to my website?
A chatbot lives on top of your product. An AI web application has AI inside the workflow: it reads from your database, writes to your audit log, respects your auth, and integrates with the systems your team already uses. We build the second one. We do not sell standalone chatbots.
Can you work with our existing Next.js or React codebase?
Yes. Most engagements drop into an existing repository. We follow your existing patterns, branch model, and review process. Code review goes both ways.
What does a typical AI web app build cost?
An AI feature added into an existing web app starts at €10,000-€25,000. A full custom AI web app usually sits in the €50,000-€100,000 range. Discovery week gives a defensible number before you commit.
How long does it take to ship a production AI web app?
A focused MVP ships in 3 weeks. Hardening and production deploy add 2-6 weeks depending on scope. Most full builds reach production in 6-12 weeks total.
Do you build the web app or just the AI layer?
Both. Most projects need the full-stack: auth, data model, UI, AI features, eval, observability. We ship the full thing and hand it over.
Want to scope this for your project?
Fill the project-estimate form. We reply within one business day with a preliminary scope and a rough budget bracket.