The Agency Stack — Where Free Open Source Wins, and the Narrow Case Where It Does Not

Most comparison articles are written by someone who wants you to buy something. This one is going to spend most of its length explaining why you probably should not.

An agency's core stack is time tracking and invoicing. Those two categories happen to have the best free self-hosted software in the entire small-business market — better, in several respects, than the paid alternatives. If you are an agency looking to stop paying subscriptions, your answer is very likely free, and it is not ours.

What you are currently paying

From each vendor's own pricing page:

A five-person agency on Harvest at $9/seat is $45/month — $1,620 over three years. On Clockify's mid-tier it is similar. That is a real number and it is why people go looking.

Put two rows of that table beside each other, though, and the article makes its own argument before we do. FreshBooks Lite is $23.00 a month and stops at five billable clients. Invoice Ninja's hosted free plan is $0 a month and stops at five clients (both read 5 September 2026). The same ceiling, on hosted products, $276 a year apart. We are not claiming the two products are equivalent — FreshBooks does bookkeeping Invoice Ninja does not, and a reader who needs that should pay for it. But if the five-client cap is the thing that defines your tier, one vendor charges $276 a year for the identical limit another gives away, and no comparison table we have seen puts those two rows next to each other.

Two of these vendors also run free tiers this article had never recorded, which is a poor look for a piece called "when free is the right answer." Harvest publishes a free plan of one seat and two projects, and Clockify's free plan runs to five users (both read 5 September 2026). A solo consultant with two live projects, and a five-person studio that needs nothing but timesheets, are each already at zero without leaving the incumbent.

The free answers, and they are genuinely excellent

Look for self-hosted time tracking and invoicing and the same two names come back every time — and unlike most categories, these are not compromises.

Kimai — open-source time tracking, self-hostable, with invoicing built in, actively maintained, and running on ordinary PHP hosting. The project publishes its own Clockify-alternative comparison page, which tells you how seriously it takes this market.

Invoice Ninja — an open-source invoicing platform with PDF invoices, client payments through a long list of gateways, templates, team roles and time tracking. Dozens of payment gateways. Self-hosted. Free. It is the single most capable free product in either category.

Also real: solidtime, ActivityWatch, Timewarrior, InvoicePlane, Akaunting, SolidInvoice.

If you want to stop paying for time tracking and invoicing, install Kimai or Invoice Ninja and stop reading. That is the honest recommendation for the large majority of agencies, and no paid product in this article beats it on capability.

So what is left?

Two narrow things. We are going to be precise about them rather than inflate them.

1. Deployment reality

Invoice Ninja v5 typically wants nginx + php-fpm + a queue worker + a scheduler, with MySQL and Redis. That is a normal stack for anyone who runs servers, and it is a wall for a five-person design studio whose "IT" is a cPanel login and a domain.

Kimai is friendlier here and runs on ordinary hosting — so if shared hosting is your constraint, evaluate Kimai first, not us.

Where a simpler paid tool fits is the narrow band where even Kimai is more system than the job needs: Clockora is a staff timesheet — $69.00 one time (product page, read 2026-08-20) — that installs on shared hosting with no Composer, no queue, no Redis.

Try the Clockora demo ↗Live, on sample data, no sign-up.

2. Scope you cannot outgrow

This is the more interesting difference and it is a design decision, not a limitation:

"Does Clockora invoice or bill these hours?" — "No — and that is deliberate. It records hours worked and approves them; it applies no billing rate and produces no invoice."

"Is it payroll?" — "No. It computes no wages, holds no pay rates, and moves no money. The overtime feature is a flag against an hours threshold, never a pay figure."

A timesheet that holds no rates is a different object from a billing system. For an agency that bills clients, that is a missing feature. For a business that needs staff hours recorded and approved — and specifically does not want pay rates in a system the whole team can see — it is the point.

And the exactness claim is testable rather than rhetorical: "Time is stored as integer minutes and summed in PHP, with cross-midnight spans and DST handled — the shipped test suite proves it, and you can run it yourself with php tests/run.php."

The invoicing side, honestly

Invora is self-hosted invoicing at $99.00 one time. Its own FAQ, re-read 24 September 2026, draws the lines where Invoice Ninja goes further:

"Does Invora support recurring invoices?" — "Yes — weekly, every two weeks, monthly, quarterly or yearly schedules. Each cycle generates a draft for your review, and nothing is sent until you press Send."

"Does it email invoices automatically?" — "It emails an invoice when you press Send — through your own SMTP server, with the client's public link and your payment link. Since 3.2 it can also send payment reminders on a schedule you approve once: off until you switch it on, with a preview of exactly what would go out today, stopping when the invoice is paid, and paused per invoice or per client. Every attempt is recorded in a send log."

"Can it collect online payments?" — "Invora never touches a card. Paste your own Stripe Payment Link, PayPal.me or bank page and it becomes a Pay button on the client's invoice; you record the payment when it lands."

Read those three together. Against a free product with dozens of built-in payment gateways and fully automated sending, a $99 license that sends nothing without a person or a schedule the owner approved, and never processes a card, is not competing on capability and should not pretend to. Its recurring schedules and the Pay button close the gap that its 1.0 release left open, but the gateways are still yours to bring.

The honest case for it is narrow and real: you invoice a handful of clients a month, you get paid by bank transfer anyway, you want a branded PDF and a record, and you want the whole thing to be four files on shared hosting rather than a stack with a queue worker. If that is not you, Invoice Ninja is free and better.

Choosing

Kimai — you want free, capable time tracking with invoicing, on ordinary hosting. The default answer.

Invoice Ninja — you want free, capable invoicing with real payment gateways, and you can run a proper stack. The default answer for invoicing.

Clockify or Harvest — you want hosted, do not want to run anything, and the per-seat cost is acceptable. Check the seat count you are actually paying for; agencies routinely pay for leavers.

Clockora — you need staff hours recorded and approved on shared hosting, deliberately without rates or billing in the system. A narrow case, honestly stated.

Invora — low invoice volume, paid by transfer, want a branded PDF and a record on your own server, and a queue worker is not something you are going to run.

Not us — if you need built-in payment gateways, automated sending without a person pressing the button, or a stack you can extend. Invoice Ninja does all of that, for free.

The honest costs

Everything in the backup guide applies, and doubly to invoicing: an invoice register is a financial record with a retention obligation.

And a specific warning for this category: free does not mean free of work. Invoice Ninja self-hosted means you maintain a queue worker, a scheduler and Redis. That is real ongoing effort — it is simply effort instead of money, and for a technical team it is usually the better trade.

The short version

Time tracking and invoicing are the two categories where free self-hosted software is genuinely the best answer, not a compromise. Kimai and Invoice Ninja are excellent, and they are free.

The paid one-time options make sense in a narrow band: shared hosting with no container platform, low volume, no need for payment gateways, and — for timesheets specifically — a deliberate choice to keep pay rates out of the system.

If you do not sit in that band, install the free one. We would rather tell you that than take $99 for something that does less.

Next steps

• Clockora — self-hosted staff timesheet · live demo
• Invora — self-hosted invoicing · live demo
• What a freelancer pays for software every year — the same free-first test for one person
• Timesheet software without per-seat pricing and invoice software you buy once
• The SaaS Price Observatory — Clockify, Harvest, FreshBooks, Wave and every other tracked vendor, quoted from their own pages and dated

Prices are quoted from each vendor's own pricing page with the date read. Kimai and Invoice Ninja are not our products and we have described them as we found them — check them yourself before buying anything, including ours.