MID Server — Java agent installed on-premise that lets ServiceNow reach systems inside your firewall. The bridge between cloud ServiceNow and your internal network.

Discovery — Automated process that scans your network and populates the CMDB with what it finds. Keeps your CI inventory current without humans typing.

System Properties — Key-value settings that control platform behavior. Email config, session timeouts, default values. Where you tune the platform.

Plugins — Optional platform components that turn on additional features. ITSM, HRSD, CSM are all plugins. Some included, some cost extra.

Application Repository (Application Manager) — Hub where you install ServiceNow Store apps and ServiceNow-published plugins. Different from Update Sets — Update Sets move custom config, Repository handles marketplace stuff.

Scope — Application namespace that isolates your custom app from out-of-box content. Prevents your customizations from getting nuked on the next platform upgrade.

REST API — How outside systems talk to ServiceNow. Create, read, update, delete records via HTTP. Foundation of every integration.

Script Include — Reusable server-side JavaScript library. Write common logic once, call it from Business Rules, REST APIs, Flows, anywhere on the server.

Inbound Email Action — Rule that processes emails coming INTO ServiceNow. Email creates an incident, email adds a comment to a ticket, email closes a record.

Upgrade History — Tracks every platform version upgrade — what was applied, what was Skipped (your customization kept), what was Reverted (OOB version taken).

🎯 COMMON PITFALLS

Building in Production. There is no recovery from this when something breaks. Build in Dev, always.
Forgetting which Update Set was active. You build a UI Policy in Dev, never set the active update set, the change goes into