Build an AI Agent (2026). Tool Stack

Ship AI-powered products. LLM APIs, vector databases, hosting, and payments, the AI agent builder stack.

Your AI agent toolkit

Reasoning, data, hosting, payments, comms.

Our Pick: LLM API
Claude API
Pay-as-you-go

Best-in-class reasoning, huge context windows, and tool-use built in. The go-to for agents that need to think through complex tasks, write code, or handle multi-step workflows.

200K context window for long documentsNative tool use and function callingSuperior reasoning for complex agent tasks
Also consider
OpenAI GPT-4o

Largest ecosystem and plugin library

Biggest developer community, most third-party integrations. Assistants API with built-in RAG. Better if you need vision, DALL-E, or Whisper in the same pipeline.

Google Gemini API

Generous free tier and multimodal

Free tier is hard to beat for prototyping. Native multimodal (text, image, video, audio). Good if you need Google Search grounding or are in the GCP ecosystem.

Groq

Fastest inference speed available

Absurdly fast token generation. Run open-source models (Llama, Mixtral) at speeds that feel instant. Great for latency-sensitive agent loops.

Our Pick: Hosting & Deploy
Vercel
Free tier

Push to Git, it deploys. Edge functions for low-latency AI responses, serverless for background jobs, and the AI SDK for streaming LLM responses to your frontend.

Vercel AI SDK for streaming LLM responsesEdge and serverless functions built inPreview deployments on every PR
Also consider
Railway

Better for long-running agent processes

No 60-second function timeout. Run persistent Python or Node processes. Better for agents that need to run for minutes, not seconds. Simple pricing.

Fly.io

Global edge deployment with containers

Deploy Docker containers close to your users worldwide. Great for AI APIs that need low latency. More control than Vercel, less config than AWS.

Cloudflare Workers

Cheapest at scale with edge AI

Workers AI runs models at the edge. Vectorize for embeddings. D1 for SQL. The cheapest option once you scale, but more limited runtime than Node.

Our Pick: Database & Vector Store
Supabase
Free tier

Postgres database with pgvector built in. Store your app data and vector embeddings in the same database. Auth, storage, and real-time subscriptions included.

pgvector for embeddings and RAGAuth, storage, and real-time includedRow-level security for multi-tenant agents
Also consider
Pinecone

Purpose-built vector database

If your agent is heavily RAG-based, Pinecone is optimised for vector search at scale. Serverless pricing, metadata filtering, and namespaces for multi-tenant apps.

Upstash

Serverless Redis + vector in one

Redis for caching and rate limiting, plus a vector store. Pay-per-request pricing. Great for agent memory, session state, and rate limiting API calls.

Neon

Serverless Postgres with branching

Scales to zero when idle. Database branching for dev/staging. pgvector support. Better if you want pure Postgres without Supabase's opinionated layer.

Our Pick: Payments
Stripe
2.9% + 30c per txn

Usage-based billing for AI products. Metered billing for token usage, subscriptions for tiers, and Checkout for one-click payments. The standard for SaaS billing.

Metered billing for usage-based AI pricingSubscriptions, one-time, and hybrid modelsCustomer portal for self-serve management
Also consider
Lemon Squeezy

Merchant of record, handles tax

They handle VAT, sales tax, and compliance globally. Higher fees but zero tax headaches. Better for solo founders who want to focus on building.

Paddle

Enterprise-grade merchant of record

Full merchant of record with better enterprise features than Lemon Squeezy. Handles invoicing, tax, and compliance. Popular with B2B SaaS.

Our Pick: Transactional Email
Resend
Free (100 emails/day)

Modern email API built for developers. Send onboarding emails, usage alerts, and billing receipts with React Email templates. Clean DX, great deliverability.

React Email for beautiful templatesSimple API, great developer experienceGenerous free tier for early stage
Also consider
Postmark

Best deliverability in the business

99%+ deliverability rate. If your emails absolutely must land in the inbox (password resets, billing alerts), Postmark is the gold standard.

SendGrid

Highest volume free tier

100 emails/day free. Proven at massive scale. More features than Resend but clunkier DX. Good if you need marketing email too.

Launch Kit

Get the full launch checklist

Every tool pre-configured, setup order mapped out, integrations documented. Skip weeks of research.

Ready to build your agent?

Pick your LLM, wire up the stack, and ship something users love.

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