The Agency Automation Stack
Seven tools for building client automations you can resell, maintain, and bill for every month.
You build automations for clients, or you run an agency where delivery margin depends on how little of the work a human touches.
Zapier Professional
Client-Facing Automation
9.4/10
Make
High-Volume Automation
Notion
Documentation & Handover
9.4/10
Airtable
Operational Database
Slack
Alerts & Client Comms
Mailgun
Transactional Sending
Stripe
Retainer Billing
Why These 5 Tools Work Together
Run Zapier and Make together on purpose. Zapier for client-owned workflows they need to understand, Make for the high-volume internal ones where per-task pricing would eat the retainer.
Document every build the day you ship it. Undocumented automations are technical debt with your name on the invoice.
Own the transactional sending. Client email problems become your emergency if their marketing domain is doing the sending.
The combined workflow: Scope and document builds in Notion, hold client data in Airtable, build client-facing workflows in Zapier and high-volume ones in Make, report status into Slack, send transactional mail through Mailgun, and bill the monthly retainer with Stripe.
Who This Stack Is For
Automation agencies live or die on two numbers: how fast you can build a client workflow, and how much of your month goes to maintaining the ones you already shipped. This stack is chosen for both. Zapier Professional is the client-facing default because clients recognise it, can log in themselves, and will not panic at handover. Make is what you use when volume makes Zapier's per-task pricing absurd — the same workflow can cost a fifth as much, and the visual builder handles branching logic Zapier makes ugly. Running both is not indecision, it is margin. Notion is the delivery layer: SOPs, workflow documentation, and a per-client wiki so a handover is a link rather than a call. Airtable is the operational database sitting under most client builds — the place records live between systems. Slack keeps internal and client comms out of email and gives your automations somewhere to report. Mailgun sends the transactional mail your builds generate, on a domain you control rather than the client's shared reputation. Stripe bills the retainer that pays for all of it. Roughly $400-600/mo for a small team, and every line is billable back.
How the Stack Fits Together
- 1. ScopeNotion
Workflow spec, client wiki, and the SOP for handover.
- 2. StoreAirtable
The operational database every automation reads and writes.
- 3. BuildZapier / Make
Client-facing workflows and high-volume internal scenarios.
- 4. NotifySlack + Mailgun
Internal alerts and client-facing transactional mail.
- 5. BillStripe
Retainer on card file, invoiced automatically.
Your Stack, Tool by Tool
A breakdown of each tool, what it does in this stack, and how to get started.
Zapier Professional
Client-Facing Automation
The automation tool clients already know. Multi-step Zaps, paths, and error handling, with a UI a non-technical client can maintain after handover.
Key feature: Shared workspaces so builds live in the client's account, not yours.
In this stack: Connects the client's CRM, forms, and billing to your Airtable layer.
Make
High-Volume Automation
Visual scenario builder priced per operation, which makes six-figure monthly run rates affordable. Handles branching and iteration Zapier struggles with.
Key feature: Roughly a fifth of Zapier's cost at high volume for equivalent work.
In this stack: Runs the internal and high-volume jobs feeding the same Airtable bases.
Notion
Documentation & Handover
Every build documented with a diagram, trigger list, and failure plan. This is what turns a one-off project into a maintenance retainer.
Key feature: Per-client wikis you can share as the deliverable itself.
In this stack: Links to every Airtable base and Zapier or Make scenario you maintain.
Airtable
Operational Database
The record layer under most client builds. Automations read and write here, and interfaces give the client a view without database access.
Key feature: Interfaces ship a usable client app on top of the data in an afternoon.
In this stack: Central store for Zapier and Make; source data for Mailgun sends.
Slack
Alerts & Client Comms
Where your automations report success and failure, and where clients reach you without email threads. Failure alerts in a channel beat discovering a broken Zap next month.
Key feature: Slack Connect channels per client plus a dedicated automation-alerts channel.
In this stack: Receives error notifications from every Zapier and Make scenario you run.
Mailgun
Transactional Sending
API sending for the notifications your builds generate, with logs you can show a client when they ask whether the email actually went out.
Key feature: Per-message logs and webhooks for delivery, open, and bounce events.
In this stack: Called by Make and Zapier; delivery events written back to Airtable.
Stripe
Retainer Billing
Recurring retainers on card file with automatic dunning. Automation agencies with card-on-file retainers get paid on time; the ones sending PDFs do not.
Key feature: Subscriptions plus usage-based billing for maintenance tiers.
In this stack: Payment events flow into Airtable and trigger Slack notifications.
What This Stack Costs
A clear breakdown of each tool's pricing for this persona.
| Tool | Free Plan? | Starting Price | Best Plan for Agency Automations |
|---|---|---|---|
| Zapier Professional | Yes | $49/mo | Professional / Team ($49-69/mo) |
| Make | Yes | Free / $9/mo | Pro ($16-29/mo) |
| Notion | Yes | $10/user/mo | Business ($15/user/mo) |
| Airtable | Yes | $20/user/mo | Team ($20/user/mo) |
| Slack | Yes | Free / $8.75/user/mo | Pro ($8.75/user/mo) |
| Mailgun | No | $15/mo | Basic ($15-35/mo) |
| Stripe | Yes | 2.9% + 30¢ | Billing (pay as you go) |
| Estimated total monthly cost | ~$480/mo for a small team | ||
Prices as of April 2026. Most tools offer free trials.
Get Started in 30 Minutes
Sign up in this order to get the most value with the least friction.
- 1
Notion
Create a build template: trigger, steps, error handling, owner, and review date. Every project starts from it.
- 2
Airtable
One base per client, same schema pattern each time. Reusability is the whole margin.
- 3
Zapier Professional
Build client-facing workflows inside the client's own workspace so handover is clean.
- 4
Make
Move anything over roughly 2,000 monthly tasks here. Recalculate the saving quarterly.
- 5
Slack
One #automation-alerts channel wired to every scenario's error handler.
- 6
Mailgun
Set up a sending subdomain per client with SPF, DKIM, and DMARC before go-live.
- 7
Stripe
Retainers as subscriptions with card on file. Never invoice maintenance manually.
Swap-In Alternatives
Nothing here is sacred. If one tool does not fit how you work, these are the substitutions we would make.
Make → n8n
Self-hostable with no per-operation cost; you own the maintenance.
Airtable → Supabase
Real Postgres when a client build outgrows record limits.
Mailgun → Brevo
Simpler if the client also needs marketing sending in the same account.
Notion → ClickUp
Better if you bill hours and need native time tracking.
Bonus Tools Worth Adding
Optional additions once the core stack is running smoothly.
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Who This Stack Isn't For
If any of these sound like you, a different Stack Pack will serve you better.
Agencies whose deliverable is content rather than workflows.
Check out The Content Agency StackSolo operators automating their own business only.
Check out The Solopreneur Business Stack
Related Reviews & Comparisons
Zapier Professional Review
Client-Facing Automation
Make Review
High-Volume Automation
Notion Review
Documentation & Handover