Every company runs on approvals. Purchase orders, leave requests, expense claims, asset purchases — each one sits in somebody's queue waiting for a yes or no. Without a central place to handle them, approvals scatter across emails, spreadsheets, and half-remembered hallway conversations. My Inbox is SAP's answer: one Fiori app where every workflow task lands, no matter which system or process created it.
If you're preparing for interviews, here's the one-line version: My Inbox is the central approval workplace where users claim, approve, or reject workflow tasks across systems. The rest of this post shows how it actually works day to day.
What My Inbox is — and what it isn't
My Inbox is a Fiori application, not a workflow engine. The workflows themselves run in the backend — SAP Business Workflow, or processes built in SAP Build Process Automation. My Inbox is the window into all of them: it collects the open tasks assigned to you and presents them in a single task list.
That distinction matters in interviews. My Inbox doesn't create approvals; it surfaces them. A task appears in your inbox because a workflow step assigned it to you (or to a group you're in). You act on it, and the workflow moves on.
Technically, My Inbox talks to backend systems through the Task Gateway service (the IW_PGW system alias in a Gateway setup). One inbox can aggregate tasks from several connected systems, which is why approvers don't need to log into each backend separately.
My Inbox is the inbox, not the post office. Workflows run in the backend; My Inbox only collects and displays the tasks waiting for you.
A task's journey: from list to decision
Open My Inbox and you see your task list — purchase requisitions waiting for release, leave requests pending approval, invoice exceptions needing a decision. Select a task to see its details: the business data, a history of previous approval levels with comments, and any attachments the requester uploaded.
Three actions cover most of the daily work:
- Claim — reserves a task for your user ID so you can work on it. This matters when a task is sent to several people at once: claiming tells everyone else "I've got this."
- Approve / Reject — the decision. Approving moves the workflow to the next step (or completes it); rejecting stops the process. A comment dialog usually appears, and for rejections a reason is typically required so the requester knows why.
- Release — the opposite of claim. It puts the task back into the shared pool, for example when you realize a colleague is better placed to decide.
Two more buttons appear depending on configuration: Forward, which hands the task to a colleague (who also needs the right authorizations), and Resubmit — also called Suspend — which hides the task from your list for a while. That's handy when you're waiting on extra information before deciding.
A concrete example: a purchase requisition for new laptops is created. The workflow determines the cost center owner as approver, and a task lands in their My Inbox. They open it, check the line items and the attached supplier quotation, then click Approve with a short comment. The workflow continues to the next approval level automatically. Had they clicked Reject, the process would have ended there and the requester would have been notified.
Where the Approve and Reject buttons come from
This surprises newcomers: the decision buttons aren't hardcoded in the app. They're defined per workflow in the backend customizing, where each decision is registered as positive (green, e.g. Approve) or negative (red, e.g. Reject). That's why one task shows Approve/Reject while another shows Approve/Reject/Rework — the workflow template decides.
The same customizing controls whether the comment dialog appears and whether a comment is mandatory. If you've ever wondered why some approvals ask for a comment and others don't — that's the setting.
Different buttons on different tasks is normal. The workflow template — not the My Inbox app — defines which decisions are available.
Substitution: approvals don't stop when you do
Approvals stall when approvers go on leave. Substitution management solves this: you nominate a substitute who receives your tasks during a planned absence, and you can define rules for unexpected absences too. Planned substitutions are managed from the user menu, and they're synchronized with SAP Task Center — so substitutes can work through whichever inbox they open.
My Inbox vs SAP Task Center
Worth knowing for interviews: SAP Task Center is the strategic successor — a unified inbox on BTP that also pulls in tasks from SAP Build Process Automation and SuccessFactors. But My Inbox remains the standard approval workplace in S/4HANA on-premise landscapes. On features, My Inbox currently supports comments and attachments on tasks; Task Center is still catching up on some of these.
Interview quick answers
What is the SAP Fiori My Inbox app used for?
Processing and approving workflow tasks from a single inbox. It's the central approval workplace where users claim, approve, or reject workflow tasks across systems.
What does "claim" mean in My Inbox?
Reserving a task to your user ID — used when a task is assigned to multiple people at once. Release is the reverse.
Who defines the Approve/Reject buttons?
The backend workflow customizing, per workflow template. Positive decisions render green, negative ones red.
Which approval workflow did you find trickiest to set up — the workflow itself, or the My Inbox side? Share it in the comments.