Five MCP servers that make building mobile apps easier

A coding agent that can only see your code is working blind. It cannot tell you why a user’s sign-in failed last night, whether the subscription product exists in the store, or which screen people leave on. These five servers give it eyes on the live app. Each one has saved me hours on an app I launched this year, and each takes a few minutes to connect.

What an MCP server does

An MCP server is a small service that exposes a product’s features as tools an agent can call, so the agent can query your database or read a crash report the same way it reads a file. Each of the five below is published by the company that makes the product, and each connects to Claude Code and Codex with a URL and a sign-in.

1. Supabase

What the agent can do: see the live database, set up authentication, and run backend code without a server.

Connected to Supabase, the agent can list the tables and the migrations, run a query against the real data, check the security advisors, and deploy an edge function, the code that runs on Supabase’s servers rather than in the app. On my project it does the read-only work: checking that the deployed database matches the migration files, debugging the row-level security policies that decide which rows each user may see, with a quick query, and running the security advisors before every release.

One rule I keep: never apply a migration through the server. It stamps its own timestamp on the change, and the migration files in the project drift away from what is live. Migrations go through the project’s own push command; the server reads, checks and deploys functions. Supabase’s documentation also offers a read-only mode, which is the safer default for an agent that mostly needs to look.

2. Expo

What the agent can do: see the app running, read the device logs, and take screenshots for you.

Expo’s server knows the Expo SDK and its documentation, and with the optional local package it can reach a running development build: take a screenshot of the simulator, find a view on screen, read the app’s logs and the router’s map of screens. It is configured in both Claude Code and Codex on my project with per-tool approval, so the agent asks before it taps anything. It is the one on this list I use least day to day, because most of the time I am looking at the phone myself; it earns its place when the agent is debugging a screen I cannot see.

3. RevenueCat

What the agent can do: manage payments across iOS and Android, set up products and subscriptions, and see who is paying.

RevenueCat sits between the app and the two stores’ billing systems. Its server lets the agent read and change the project’s apps, products, entitlements (what each purchase unlocks) and offerings (which products are shown together) without a dashboard login, so setting up a new subscription tier or checking which entitlement a product unlocks happens in the conversation. On my project it runs locally, started through a secrets wrapper so the API key never sits in a config file. Managing payments across both stores is RevenueCat’s job as a product; the server puts that job in the agent’s hands.

4. Sentry

What the agent can do: read crash reports from real users, point to the code that caused each one, and prepare a fix for you to review.

Sentry collects every crash and error from users’ phones, with the stack trace that led there. Through the server, the agent reads the issues as they come in and goes straight to the lines in your code. This is the one that changed how I work: since August a scheduled routine on my project reads the qualifying issues every morning, root-causes up to three of them against the repository, opens a pull request, a proposed change I can read and merge, when the fix is small and a GitHub issue when it is not, and posts a summary. A qualifying issue is an error or fatal, unresolved, seen in the last seven days, hitting two users or five events. The server supplies the reports and the code locations; the agent writes the fix; I decide what merges.

5. PostHog

What the agent can do: build custom funnels, show where users drop off, and turn features on and off remotely.

PostHog is the analytics. Its server lets the agent run queries, check the top errors, and create insights and dashboards from the chat. My project’s seven funnels and its streak insight were built this way and attached to one dashboard in one session, and the agent has answered questions about user behaviour with queries ever since. Feature flags, which turn a feature on or off for users without a new release, are part of what the server exposes; on my project that is still done by hand.

Connecting them

All five are hosted: you add a URL to your agent’s MCP configuration and sign in through the browser the first time. Each vendor documents the exact steps for Claude Code, Codex and the other clients.

The URLs and the sign-in methods are as each vendor’s page described them on 31 October 2026. Before you connect one, read its page: the vendors add tools and change the authentication from time to time, and the agent should only ever hold the permissions you would give a new team member.