tool-calling
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Alex Salazar Is Building the Permission Layer for AI's Hands
Before Arcade could help AI agents act, its founders had to let their first idea fail. Alex Salazar's career explains why the useful product was hiding in the permissions underneath.
StackOne
StackOne is a London-based integration platform that gives B2B SaaS companies and AI agent builders a single unified API to connect to hundreds of enterprise systems - from HR and CRM to ticketing, messaging and identity. Combining a proprietary tool-calling LLM with a real-time, privacy-first engine, it offers 200+ pre-built connectors and thousands of ready-made actions so agents can reliably and securely take actions inside the software businesses already use. Founded in 2023 by Romain Sestier and Guillaume Lebedel, the company raised a $20M Series A led by GV (Google Ventures) in May 2025 and has surpassed 1 billion API calls.
Mastra
Mastra is an open-source TypeScript framework for building production-ready AI agents, workflows, and retrieval-augmented generation pipelines. Built by the team behind Gatsby, it gives developers agents, durable workflows, memory, RAG, tool calling, evals, and observability in one stack - so JavaScript and TypeScript engineers can move from prototype to production without leaving their language. Mastra is developed by Kepler Software, a San Francisco startup, and reached 25,000+ GitHub stars and 300,000+ weekly npm downloads with adoption at companies like Brex, Sanity, Replit, and PayPal.