Glossary

Every term, plain English.

• Frontend
  The part the user sees and clicks.

  Runs in the browser. Cannot keep secrets. Sends requests to the backend.

• Backend
  The trusted server-side part.

  Runs on a server or serverless function. Owns auth, validation, and database access.

• Database
  Long-term structured storage.

  Tables of records the backend reads and writes. Survives across sessions.

• Browser
  The program that runs your frontend.

  Chrome, Safari, Firefox. Renders HTML/CSS and runs JavaScript.

• Record
  One row in a table.

  A single instance of a thing — one wedding, one task, one contact.

• Field
  One labeled value on a record.

  A column. Each field has a type.

• Table
  A collection of records with the same shape.

  Schema defines the columns. Indexes make reads fast.

• Schema
  The shape of your data.

  Declares tables, fields, and types. Enforced by the database.

• Function
  A named action with inputs and an output.

  Reusable, testable, composable. Components and event handlers are functions.

• Input
  A value passed into a function.

  Usually typed in TypeScript.

• Output
  What a function returns.

  The result of calling the function.

• Permissions
  What a user is allowed to do.

  Enforced server-side in Convex functions (getActor / tenant checks).

• API
  A contract for talking to another system.

  Usually HTTP endpoints with typed request/response shapes.

• API key
  A secret token identifying your app.

  Keep on the server in env vars. Never ship to the browser.

• Webhook
  An external service calling your URL.

  Configure the URL with the provider. Verify signatures before processing.

• REST
  A convention for HTTP APIs.

  Resources + verbs (GET, POST, PUT, DELETE).

• JavaScript
  The language that makes the web act.

  Runs in the browser and on servers (Node, Bun, Deno).

• TypeScript
  JavaScript + a shape checker.

  Adds types that are checked at build time and erased at runtime.

• Type
  A description of a value's shape.

  string, number, { id: string }, etc.

• any
  The TypeScript escape hatch.

  Turns off checking for that value. Avoid.

• State
  Data the screen remembers right now.

  Local to a component. Lost on refresh unless persisted.

• React
  A library for building UI from components.

  Function components + hooks; declarative re-render on state change.

• Component
  A reusable piece of UI.

  A function that returns JSX. Takes props.

• Props
  Inputs to a component.

  Read-only inside the component.

• Vite
  Dev server + production builder.

  Fast HMR in dev, Rollup-based build in prod.

• Build
  Packaging source into deployable files.

  Output usually lands in dist/.

• Dev server
  Local server with hot reload.

  Run with `npm run dev`.

• Route
  A URL that maps to a screen.

  Static (/about) or dynamic (/events/:id).

• Dynamic route
  A route with a parameter slot.

  Like /events/:id — :id is filled per visit.

• Params
  Values pulled from a dynamic route.

  Available via a useParams-style hook.

• Convex
  Realtime-first backend platform.

  Schema + queries + mutations + actions + storage + auth in one.

• Query (Convex)
  A read function. Live and cached.

  Deterministic; same input → same output.

• Mutation (Convex)
  A transactional write.

  Atomic; no external calls allowed.

• Action (Convex)
  A non-transactional function.

  Allowed to call external APIs. Persist results via a mutation.

• Convex .site URL
  HTTP entry for webhooks.

  https://<slug>.convex.site — httpActions; separate from .cloud client URL.

• PostgreSQL
  A mature relational database.

  SQL, transactions, indexes, constraints.

• RLS (Row Level Security)
  Per-row authorization in Postgres.

  Policies decide who can SELECT/INSERT/UPDATE/DELETE each row.

• SQL
  The query language for relational databases.

  SELECT, INSERT, UPDATE, DELETE.

• Deployment
  Putting a built app on a public URL.

  Build → upload → serve.

• Environment variables
  Per-environment secrets and config.

  Set in the host dashboard or a .env file.

• Vercel
  Managed hosting for React/Next/TS apps.

  Git-based CI, preview URLs, serverless functions.

• Cloudflare Workers
  Edge runtime at every PoP.

  V8 isolates with a constrained runtime — no full Node.

• VPS
  A rented virtual Linux server.

  You manage everything: nginx, systemd, backups, firewall.

• SSH
  Secure remote terminal.

  Encrypted tunnel; use key pairs, disable passwords.

• Terminal
  Text interface for commands.

  Where you live when on a server.

• MCP
  Model Context Protocol.

  Standard for AI assistants to use tools/resources/prompts via JSON-RPC.

• Tool (MCP)
  A function an AI can call.

  Declared with a JSON schema.

• Resource (MCP)
  Read-only data exposed to the AI.

  Files, records, lookups.

• AI coding agent
  An AI that writes/edits code.

  Codex, Claude, Cursor, etc. Treat as a junior engineer.

• Plan
  The agreed-on shape of work before code.

  Plans prevent waste and let you reject scope creep.

• Code review
  Reading a change before it ships.

  Even for solo projects with AI authors.