"Understanding OAuth 2.0 Protocol" matching MCP connectors:

Solana-native MCP gateway for SAP, DeFi tools, SNS identity, and x402 payments.

Conta Azul ERP MCP — sales, customers, finance and NF-e via OAuth 2.0. Read + write, 35 tools.

Chat-first business management. 22 industry templates, 14 widgets. Manage clients, sales, inventory via natural language. OAuth 2.0 authentication.

Malaysian SME accounting, e-Invoice and payroll books for your AI. 37 tools — business snapshot, P&L, balance sheet, A/R and A/P aging, cash forecast, stock, tax position, document search — plus draft-only writes (invoice, quote, receipt, bill, expense, contact, bank statement import). Every write is a pending draft a human approves in Taokeh; it can never post, edit or delete. Remote Streamable HTTP at https://taokeh.my/mcp, OAuth 2.1 or a personal access token.

[A4B](https://a4b.ai/) is a flat-rate CMMS (asset & maintenance management) that ships a native MCP server — an integration still uncommon in the CMMS category. AI assistants like Claude and ChatGPT can query asset inventory, create and update assets and maintenance tasks, search history, and generate reports. Secured with OAuth sign-in, audit logging, and per-organization isolation. Docs: https://docs.a4b.ai/mcp/

BakeryOS bakery-management MCP — recipes, costs, production; propose changes via OAuth.

Connect Exact Online accounting to Claude, ChatGPT and Copilot. 75 tools, OAuth 2.1, EU-hosted.

MCP server enabling AI agents to manage Bitrix24 features via standardized protocol