Resser Solutions

Tooling · · 7 min read

The Best AI Tools for B2B SaaS in 2026 (That Engineering Teams Actually Use)

A curated stack of AI tools we ship to production at Resser: models, frameworks, retrieval, eval, observability, hosting.

Written byAlen Žarković, CEO and Tech LeadAsk us first →

Best AI tools for B2B SaaS in 2026: here's the tight stack we actually ship at Resser Solutions. Curated for production survival, not Twitter likes.

Models

  • Anthropic Claude Sonnet (default for agents).
  • OpenAI GPT-4o / o-series (structured extraction).
  • Google Gemini (long context, vision).
  • Llama 3 70B / Mistral / Qwen 2.5 (open-weights when sovereignty demands).

Frameworks

  • LangGraph: stateful multi-step agents.
  • Vercel AI SDK: streaming UIs and tool calls.
  • Pydantic AI: type-safe Python agents.
  • Anthropic / OpenAI SDKs directly when frameworks add friction.

Retrieval and storage

  • pgvector: default for 95% of cases.
  • Qdrant: heavy filtering and hybrid search.
  • Pinecone / Turbopuffer: managed at scale.
  • Voyage AI / Cohere: embeddings.
  • Cohere Rerank: reranker for production RAG.

Eval and observability

  • LangSmith: hosted eval and traces.
  • Braintrust: CI-driven eval.
  • Promptfoo: CLI eval that blocks PRs.
  • Helicone: cost and latency observability.

Deploy

  • Vercel: Next.js apps and edge.
  • AWS / GCP / Azure: enterprise.
  • vLLM: open-weights inference on customer GPUs.
  • Supabase / Neon: Postgres with pgvector built-in.

FAQ

Frequently asked.

Why not LangChain?

We use LangGraph (its successor for stateful agents) heavily. The original LangChain 'chains' abstraction added more friction than value in production. LangGraph is a clean improvement.

Why Vercel AI SDK over rolling your own?

Vercel AI SDK saves a week of glue code for streaming, tool calls, and structured outputs. The bundle cost is small and the API is clean. For non-React backends we use the provider SDKs directly.

When do you use no-code tools?

For prototyping or for problems that are genuinely generic (lead routing, simple email triage). For production custom AI features, no-code becomes a liability when you need eval, cost telemetry, or per-tenant rollout.

How fast does this stack change?

Models update quarterly. Frameworks update on a 6-12 month cadence. The deployment + observability layer is the most stable. We review this list every 3 months and rotate items in / out based on what we shipped.

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