A curated list of production-ready MCP servers for developers building with Claude, Cursor, ChatGPT Codex, and Gemini. Covers email, databases, cloud, and developer tools.
MCP adoption is moving fast. There are hundreds of MCP servers on registries like Smithery, PulseMCP, and mcp.so, and quality varies wildly. This list is a curated set that's actually worth using in production, grouped by category.
We include one of ours (Nitrosend) and say exactly where it sits in the ecosystem.
The bar for an MCP server is whether an agent can finish the job with it, not whether a server exists. George Hartley, Nitrosend's co-founder, hit that bar from the user's side before he built one. On The Breakout CEO in August 2026 he said of the email tools he tried: "most of them didn't even have MCP connectors and the ones that did, you couldn't do the right stuff." Once a server does the whole job, he wrote on LinkedIn in September, "You ship one MCP server and your product turns up in places you haven't been yet".
The reference MCP server from Anthropic. Read, write, list files on the local filesystem. Anchor example of how MCP tools should be shaped.
Best for: Local dev, anything where the agent needs to read/write project files.
Pricing: Free, open source.
MCP: stdio. No auth.
Read repos, open issues, manage PRs, trigger workflows. The single most-used MCP server in the coding agent ecosystem.
Best for: Any coding agent workflow touching source control.
Pricing: Free, open source.
MCP: Remote HTTP with GitHub OAuth.
Nitrosend (email)The AI-native email MCP: campaigns, flows, contacts, segments, tests, approvals, and deliverability, plus Brand Kit auto-generates every email in your brand's own colors, fonts, and voice. Workflow surface, not just one-shot send.
Best for: Anyone building apps where an agent operates campaigns, lifecycle flows, audiences, and deliverability while transactional app sends stay in the API or SDK, without a designer in the loop for every send.
Pricing: Free 5,000 emails to start, then 500/mo. Paid from $20/mo.
MCP: Remote HTTP with OAuth. Also a listed plugin in the ChatGPT plugin directory.
Read-only and read-write Postgres MCP servers. Let agents query databases safely with schema introspection.
Best for: Analytics, debugging, any query-heavy agent task on a Postgres-backed product.
Pricing: Free, open source.
MCP: stdio. Connection string auth.
Issues, projects, cycles, assignments. The most mature project-tracker MCP.
Best for: Teams on Linear who want the agent to plan and log work as it codes.
Pricing: Free, included in Linear.
MCP: Remote HTTP with Linear OAuth.
Read channels, send messages, read DMs, search history. Useful for agents that need organizational context.
Best for: Agents that run on behalf of a team and need to report or ask.
Pricing: Free, Slack limits apply.
MCP: Remote HTTP with Slack OAuth.
This list includes Nitrosend, our product, ranked on the same production-readiness, auth, coverage, docs, and maintenance criteria as everything else here. It sits at #3 because that is genuinely where it ranks against these specific tools: it is the best option in this list for email specifically, not a database or issue tracker. Pricing and feature claims accurate as of September 2026.
