Your team is in Slack all day. Stand-ups happen there. Project decisions happen there. Even the Friday gif wars happen there. But when someone submits an expense? Suddenly, they’re emailing a PDF, DMing their manager, and following up three days later because nobody saw the original message. The expense approval process doesn’t have to live somewhere else. Here’s how to approve expenses in Slack properly — with a real audit trail, automatic routing, and zero context switching.
How do you approve expenses in Slack?
You can approve expenses in Slack either using Slack’s native Workflow Builder for basic setups or a dedicated Slack-native expense tool like ExpenseTron for full expense management. The ideal setup lets employees submit an expense (with receipt, amount, and category) directly in Slack, automatically routes it to the right approver, and lets that manager approve or reject with one click — all without leaving Slack. Approved expenses then sync to your accounting software automatically.
Why expense approvals break down in the first place
Most small and growing teams don’t have a broken expense approval process because they’re disorganised. They have a broken one because they never actually built one. Expenses got approved through a DM here, an email there, a verbal “yeah that’s fine” in the corridor — and it worked, until the team grew past ten people and month-end became a full-day archaeology project.
When approval requests live in scattered messages rather than a structured workflow, teams lose the audit trail, clear chain of responsibility, and predictable turnaround times they need as they scale. The fix isn’t a new policy document. It’s moving the expense approval workflow into the same place your team already communicates — Slack — and making the process impossible to miss.
Option 1: Slack’s native Workflow Builder (free, basic)
If your expense approval process is simple — one approver, one tier, straightforward submissions — Slack’s built-in Workflow Builder can handle it without any third-party tool.
Here’s how it works:
In Slack desktop, click your workspace name, go to Tools, then Workflow Builder. Create a new workflow from scratch, name it something clear like “Expense Approval,” and set it to trigger via a shortcut. Build a form that collects the fields your approver needs — amount, category, receipt, and a brief description. Then set the next step to send that form response to the manager or a dedicated channel like #expense-approvals, with Approve and Deny buttons included. Configure what happens after each decision: an automatic DM to the employee confirming approval or explaining the rejection.
This gets you a basic expense approval workflow in Slack with no additional cost. The limitations show up quickly, though. Multi-stage sign-offs — like manager first, then finance — require manual branching and max out at five paths. There’s no accounting sync, no audit log outside of Slack’s message history, and no automatic reimbursement notification. For a team of five or six, it’s fine. For a growing team with more than one approval tier or multiple currencies, you’ll outgrow it fast.
Option 2: A dedicated Slack-native expense tool (recommended)
For teams that need a proper expense approval process — with routing rules, accounting sync, audit trails, and reimbursement tracking — a purpose-built Slack expense tool is the right call.
This is exactly what ExpenseTron is built for. The entire expense management workflow lives inside Slack. No separate portal, no second login, no dashboard your manager has to remember to check.
Here’s what the expense approval workflow looks like end-to-end:
Step 1 — Employee submits the expense in Slack
They message ExpenseTron directly, attach a photo of the receipt, enter the amount and category, and add a note. Takes about thirty seconds. The submission is logged immediately with a timestamp.
Step 2 — ExpenseTron routes it to the right approver automatically
Please avoid manual forwarding and “hey, did you see my expense” follow-ups. The right manager gets a Slack notification with the full expense details and a one-click Approve or Reject button.
Step 3 — The approver acts directly in Slack
One click. If they reject it, they add a short note explaining why. The employee is notified either way instantly.
Step 4 — Approved expenses sync to accounting automatically
ExpenseTron connects natively with QuickBooks Online and Xero, so every approved expense flows into your books without anyone re-entering data. Many studies tell us that best-in-class companies process expense reimbursements in 3.5 days on average — manual processes average more than 7. Automated Slack-based approvals get you much closer to that 3.5-day benchmark.
Step 5 — Employee gets reimbursed and notified
No chasing, no wondering. The reimbursement confirmation comes through Slack.
If you’re also wondering why your team keeps delaying expense submissions in the first place, the answer is almost always friction in the submission step — which disappears when it lives in Slack.
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How to set up a proper expense approval workflow in Slack
Whether you use Slack’s native builder or a dedicated Slack expense tracking tool, these are the decisions you need to make before turning anything on.
Define your approval tiers first
Who approves what? For most small teams, anything under £100/$100 goes to a direct manager, anything over £500/$500 needs a second sign-off from finance or a founder. Get this written down before you configure anything. Ambiguity here is the single biggest cause of approval delays.
Set a submission deadline
Expenses submitted within 7 days of the transaction is a reasonable standard. Beyond 14 days and you’re chasing people for receipts they’ve already lost. Make the deadline part of your written expense policy and reference it in your Slack onboarding.
Use a dedicated channel
Whether you’re using Slack Workflow Builder or ExpenseTron, route all expense submissions to a single channel — something like #expenses or #finance-approvals. A public channel provides company-wide visibility into spending, naturally encourages more thoughtful requests, and creates a central searchable log that prevents approvals from getting lost in private DMs.
Route by role, not by name
Implement dynamic routing based on roles or cost centres rather than individual names, so your workflow remains functional during team changes. If you hardcode “Sarah approves all expenses” and Sarah goes on leave, the workflow breaks.
Connect to your accounting tool
Approvals that don’t sync downstream don’t close the loop. If your finance team is still manually re-entering approved expenses into QuickBooks or Xero at month-end, you haven’t finished building the workflow.
What a good Slack expense approval looks like in practice
A product manager on your team takes a client out for lunch on a Tuesday. They open Slack, send the receipt to ExpenseTron, enter £65 and select “client meals.” Thirty seconds. Their direct manager gets a Slack notification immediately with the details and an Approve button. The manager approves it during their next message check. ExpenseTron logs the approval with a timestamp, syncs the expense to Xero, and sends the PM a confirmation in Slack. By Thursday, the reimbursement is scheduled.
No email. No follow-up. No end-of-month scramble. That’s what a properly built expense approval workflow in Slack actually looks like — and it’s not complicated to get there.
For teams comparing options, this Slack expense management comparison covers the key differences between tools in this space.
Frequently Asked Questions
Can you approve expenses directly in Slack?
Yes. With a dedicated Slack-native expense tool like ExpenseTron, managers can approve or reject expense submissions with a single click directly inside Slack — no separate dashboard or login required. Slack’s native Workflow Builder also supports basic approve/deny buttons for simpler setups, though it lacks accounting sync and advanced routing.
What’s the difference between Slack Workflow Builder and a Slack expense tool?
Slack Workflow Builder is a free native tool that lets you build basic approval forms with approve/deny buttons inside Slack. It works well for simple, single-tier expense approvals. A dedicated Slack expense tool like ExpenseTron goes further — it handles multi-currency submissions, automatic routing, accounting sync with QuickBooks or Xero, audit trails, mileage tracking, and reimbursement notifications, all natively inside Slack.
How do you set up an expense approval workflow in Slack?
Start by defining your approval tiers — who approves what amounts and categories. Then choose your tool: Slack Workflow Builder for basic setups or ExpenseTron for a full expense approval process. Create a dedicated #expenses channel, configure automatic routing to the right approver by role, and connect to your accounting software. The whole setup takes less than a day with a purpose-built tool.
Does ExpenseTron sync approved expenses to QuickBooks or Xero?
Yes. ExpenseTron integrates natively with QuickBooks Online and Xero. When an expense is approved in Slack, it syncs automatically to your accounting software — categorised and converted if multi-currency — without any manual data entry from your finance team.
How long should an expense approval take in Slack?
With a structured Slack-based expense approval workflow, most individual expenses should be reviewed and approved within a few hours of submission. Automated approvals collapse the entire process into a single interaction — approvers see the amount, category, receipt, and description in one Slack message, approve with one click, and the system logs the action and triggers the next stage automatically. Best-in-class teams achieve full reimbursement within 3.5 days of submission.
Is there an audit trail when you approve expenses in Slack?
Yes — with a purpose-built tool like ExpenseTron, every submission and approval is logged with a timestamp and tied to the employee’s record. This gives you a clean, searchable audit trail without relying on Slack’s message history, which can be hard to reconstruct and doesn’t constitute a formal financial record.
What happens if an approver misses an expense request in Slack?
With ExpenseTron, approvers receive an immediate Slack notification when an expense is submitted and routed to them. If no action is taken, the system sends reminders automatically — so nothing sits unapproved while waiting for someone to notice a message buried in a busy channel.
Can remote and international teams use Slack for expense approvals?
Yes. Slack-based expense approval is particularly well suited for remote and distributed teams because it removes the dependency on being in the same office, time zone, or even on the same working schedule. ExpenseTron also handles multi-currency submissions with automatic conversion, which makes it practical for international teams filing expenses in local currencies.
Getting your expense approval workflow into Slack isn’t a big project. The decision is really just whether you need a basic setup (Slack Workflow Builder gets you there in an afternoon) or a proper end-to-end expense management process with accounting sync, audit trails, and automatic routing (that’s what ExpenseTron is for).
Either way, the goal is the same: expenses submitted once, routed automatically, approved fast, synced to your books, and employees reimbursed without anyone chasing anyone. That’s not a high bar — it’s just what happens when the expense approval process lives where your team already works.
See how ExpenseTron handles expense approvals inside Slack →
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