The Real Cost of Replacing SaaS With an Open Source Stack

A 20-person company running Intercom, HubSpot, Calendly, Mailchimp and Typeform is paying roughly $1,300 to $1,500 a month in subscriptions, and that number climbs every time they hire. The open source equivalents of those tools are genuinely free to license, and the whole stack fits on a single server that costs less than one Intercom seat. The catch is real too: the license is the cheapest part of self-hosting, and the maintenance hours are the number most comparisons leave out.

This post prices both sides honestly. We deploy and manage this exact stack as a service, so the numbers below are the ones that decide whether it is worth doing. You will get current per-tool pricing, a three-year worked example for a 20-person company, and the cases where staying on SaaS is the correct answer.

The stack this post prices

Six open source tools cover the six categories most small companies pay SaaS for. Every one of them is production-grade, actively maintained, and free to run on your own infrastructure:

Twenty replaces HubSpot or Salesforce for CRM. It is mostly AGPLv3 with some enterprise-marked files under a commercial license, and it self-hosts with Docker Compose on PostgreSQL and Redis (GitHub, license).
Chatwoot replaces Intercom or Zendesk for customer support. MIT licensed, omnichannel out of the box: live chat, email, WhatsApp, Instagram, Telegram, SMS, and voice (GitHub).
Cal.com replaces Calendly for scheduling. One honest caveat: the open repository is now Cal.diy, a community fork with the commercial code stripped out. It is 100% MIT, but the maintainers warn it is meant for personal, non-production use and steer businesses toward Cal.com hosting or enterprise on-prem.
Plausible replaces Google Analytics for web analytics. The Community Edition is AGPLv3 and cookie-free, which usually means no consent banner for analytics (GitHub).
Listmonk replaces Mailchimp for newsletters and campaigns. A single Go binary plus PostgreSQL, AGPLv3 (GitHub). It needs an SMTP provider to actually send mail.
Formbricks replaces Typeform or Qualtrics for forms and surveys, with in-app, link, and email survey types (GitHub).

This is not a hypothetical stack assembled for a blog post. It is the set we offer as our managed open source stack service, and each tool has a real company or foundation behind it shipping releases.

What the SaaS versions cost today

All prices below are from the vendors' own pricing pages as of September 2026. They change; check before you budget.

Intercom: Essential is $29 per seat per month, Advanced is $85, Expert is $132. The Fin AI agent is billed separately at $0.99 per outcome on every plan, and Copilot is another $29 per agent per month. WhatsApp and SMS are pay-as-you-go (pricing).
HubSpot Sales Hub: free for two users, Starter from $20 per seat, Professional from $90 per seat per month billed annually with a required $1,500 onboarding fee, Enterprise from $150 per seat with $3,500 onboarding (pricing).
Calendly: Standard is $10 per seat per month, Teams is $16, and Enterprise starts at $15,000 a year with a 50-seat minimum (pricing).
Mailchimp: free under 250 contacts, Standard from $20 a month, Premium from $350 a month, and every tier steps up as your contact list grows (pricing).
Typeform: Basic $28 a month, Plus $56, Business $91 on annual billing, with response caps that push active teams up the ladder (pricing).
Google Analytics: free, but as the Plausible team puts it, GA is free because Google monetizes the data; you pay with your visitors' privacy and with the compliance overhead that follows (their framing).

Two patterns matter more than any single number. First, most of these prices are per seat, so your bill grows every time you hire, even when usage stays flat. Second, the features businesses actually need, like SSO, audit logs, and automation, sit one or two tiers above the entry price, which is how a "$29 seat" becomes an $85 seat.

What the self-hosted stack actually costs

The license line is zero. Everything else is not.

Infrastructure

All six tools run comfortably on one well-sized virtual server, with a second small one if you want headroom. Hetzner's own calculator prices an entry AMD shared-CPU cloud instance at €11.49 a month with 20 TB of traffic included, and independent stack guides put an 8 vCPU, 16 GB Hetzner box, which is more than enough for this stack at 20 users, at around €16 a month (Hetzner Cloud, OSSAlt stack guide). Add object storage for off-site backups and you are at $25 to $45 a month all-in.

Email sending

Listmonk is free, but sending 20,000 emails a month needs an SMTP relay. Amazon SES charges $0.16 per 1,000 emails on its Essentials tier with no commitment, so that volume costs about $3.20 a month (SES pricing).

The total so far

Call it $30 to $50 a month for the whole stack, for any number of employees. That is the number the cheerleading listicles quote, and it is true. It is also only half the ledger.

The cost nobody puts on the invoice: operations

A self-hosted stack does not patch itself, and the honest way to compare it against SaaS is to price your own hours. The SelfHostIndex TCO analysis makes the point well: any comparison that values your time at zero will produce whatever answer the author wanted, and a mature setup costs a couple of hours of maintenance a month plus an occasional "bad weekend" of about eight hours a year (source). That is hobbyist math. For a stack your customers touch every day, budget more:

Setup: one to three days per tool to deploy, wire up SSO, migrate data, and test. For six tools, 50 to 70 hours is realistic.
Routine maintenance: updates, security patches, backup restore tests, and certificate renewals, about 4 to 6 hours a month. A backup you have never restored is a hope, not a plan.
Incidents: one broken upgrade or expired token a year that costs a day. Eight hours is a fair budget.
The ownership question: if exactly one person understands the setup and they leave, the cost you deferred arrives in a single week.

At a loaded engineer rate of $60 an hour, that is $3,000 to $4,200 of setup and roughly $340 a month of ongoing labor. Still far below the SaaS bill, but nowhere near zero, and it comes out of someone's calendar who presumably has another job.

Worked example: 20-person company, three years, three options

Take a 20-person company with 5 support agents, 5 sales reps, 10 people taking bookings, a 5,000-contact mailing list, and 20,000 emails a month. Labor priced at $60 an hour.

Option 1: Stay on SaaS

Intercom Advanced, 5 seats: $425 a month, plus roughly $300 a month for 300 Fin AI outcomes
HubSpot Sales Hub Professional, 5 seats: $450 a month, plus $1,500 onboarding once
Calendly Standard, 10 seats: $100 a month
Mailchimp Standard: from $20 a month, climbing as the list grows
Typeform Plus: $56 a month
Google Analytics: $0
Total: about $1,350 to $1,500 a month, or $50,000 to $55,000 over three years

Option 2: Self-host the open source stack yourself

Server, backups, and email sending: $45 a month
Setup labor, 60 hours at $60: $3,600 once
Maintenance labor, 5 hours a month at $60: $300 a month
Failure budget, 8 hours a year: about $40 a month
Total: about $385 a month, or roughly $17,500 over three years

Option 3: Managed open source

A partner deploys, patches, backs up, and monitors the same open source stack on infrastructure you own, for a flat monthly fee that lands between option 2 and option 1. You keep the open licenses, the data residency, and the exit path, and the maintenance hours come off your team's calendar. This is the model we run, and it exists precisely because option 2's hidden line is the one that breaks teams.

The three-year saving of option 2 over option 1 is around $35,000. Real money. But notice what it costs: about 130 hours a year of engineering attention and a single point of failure named whoever set it up. Whether that trade wins depends entirely on whether you have that person.

When SaaS is the right choice

We sell the alternative, and we will still tell you to stay on SaaS when:

You have no one to own it. No engineer with spare operational capacity means the maintenance hours are fiction. Buy the subscription.
The tool is not core. If analytics or forms are peripheral, the vendor's $20 to $56 a month is cheaper than one incident.
You need the vendor's compliance paperwork. SOC 2 reports, BAAs, and DPAs come with the SaaS tier. Recreating that assurance yourself costs more than the subscription.
You are under about 10 app-seats. Below that, the fixed cost of running infrastructure never amortizes, which is the same conclusion the TCO math reaches.
Email deliverability is revenue-critical. Sending is a profession. Keep Mailchimp or a dedicated ESP if your pipeline depends on inbox placement.

Open source also wins some arguments SaaS cannot enter. If your regulator or your clients require data to stay in a specific jurisdiction, a stack on servers you choose, in the region you choose, answers the question structurally instead of contractually. And when a vendor sunsets a product or doubles a tier, a self-hosted stack does not get the email.

Common mistakes when teams self-host

Most failed self-hosting projects fail the same few ways:

Comparing license price to subscription price. The comparison is subscription versus infrastructure plus labor. Run both full ledgers or do not run either.
Skipping the restore test. Snapshots run nightly, nobody ever restores one, and the first real restore fails in front of customers.
Letting one person hold all the knowledge. No runbook, no documented upgrade path, and the whole saving evaporates the week they resign.
Running production on a hobbyist fork. The Cal.diy example above is the warning: read the README and the license before you bet operations on a community edition the maintainers describe as non-production.
Never revisiting the decision. SaaS prices and your headcount both move. Re-price the comparison once a year, per tool, not as ideology.

A decision checklist

For each tool you are considering, answer five questions:

Does someone on the team have 5 hours a month to own it, and a second person who has read the runbook?
Is the SaaS bill for this tool above roughly $200 a month, or climbing with seats?
Do you have a data residency or client requirement the vendor cannot meet?
Is the open source project's license and maintenance model production-grade, with releases you can track?
Can you export your data out of the current SaaS cleanly, and out of the open source tool later if you switch back?

Four or five yes answers points to self-hosting, DIY if you have the owner, managed if you do not. Two or fewer means renew the subscription with a clear conscience.

Frequently asked questions

Is self-hosted open source software really free?

The license is free; operating it is not. Budget for a server, backups, an email relay if you send mail, and several hours a month of maintenance. For the six-tool stack in this post, infrastructure runs $30 to $50 a month and labor is the larger line.

How big a server do I need for the whole stack?

An 8 vCPU, 16 GB RAM cloud server handles Twenty, Chatwoot, Plausible, Listmonk, Formbricks, and a scheduler for a 20 to 50 person company. Budget hosts sell that for around €16 to €40 a month. Plausible's ClickHouse backend is the heaviest component and the first thing to give its own resources as traffic grows.

What happens when the person who set it up leaves?

Everything deferred arrives at once, which is why a named owner, a written runbook, and tested restores matter more than the tooling. If you cannot staff that internally, a managed service is the honest answer, not heroic documentation.

Is Chatwoot actually as good as Intercom?

For core support workflows, yes: shared inbox, live chat, WhatsApp, automation rules, help center, and reporting all exist and are used by over 15,000 organizations. Intercom is ahead on product tours, in-app messaging polish, and its Fin AI agent, and Chatwoot's own cloud plans start at $19 per agent if you want hosted instead (Chatwoot pricing).

Can I self-host some tools and keep others on SaaS?

Yes, and that is usually the right answer. Self-host the tools with painful per-seat pricing or residency requirements, keep SaaS for peripheral tools and anything where the vendor's compliance paperwork is the product. The decision checklist above is per tool for exactly this reason.

How does this connect to AI agents?

The same self-hosted stack becomes far more powerful when an agent can read your CRM, answer support tickets, and trigger workflows across it, because the data and the APIs are on infrastructure you control. Anthropic's enterprise agents point the same direction from the other side, as we covered in our piece on AI agents replacing the SaaS stack, and open standards like the ones the Agentic AI Foundation is defining are what will make agents work across tools like these.

Where to go from here

If the numbers above point you toward self-hosting but the maintenance column points the other way, that middle path is exactly what we built: we deploy Twenty, Chatwoot, Cal.com, Plausible, Listmonk, and Formbricks on infrastructure you own, then patch, back up, monitor, and upgrade it for a flat monthly fee, and we wire it together with n8n workflow automation where the stack needs to talk to itself. See how the managed open source stack works, or book a call and we will run the three-option math for your actual seat counts.