Open source quotation software is genuinely useful—but only for certain users. Understanding who it serves well, and who it doesn’t, saves you from setting up a server only to abandon it two weeks later.
“Open source” and “free” aren’t quite the same thing when software is involved. Open source means the code is publicly available. Free-to-use often means you’re trading money for time—specifically, the time it takes to install, configure, and maintain the software yourself.
Here’s what’s actually available and how to decide if it makes sense for your situation.
The main open source quotation tools
Invoice Ninja
Invoice Ninja is the most widely used open source invoicing and quoting tool. It’s actively maintained, has a large community, and offers both a self-hosted version and a hosted cloud tier.
Features:
- Quotes, proposals, and invoices
- Client portal where clients can view and accept quotes
- Payment integrations (Stripe, PayPal, and others)
- Recurring invoices
- Time tracking
- Expense tracking
- Multi-currency support
Self-hosted: Free. Requires PHP 8.1+, a web server (Apache or Nginx), and a MySQL/MariaDB database. Installation documentation is solid.
Hosted free tier: Up to 20 clients, unlimited invoices and quotes. Most freelancers starting out will fit within this limit.
Paid hosted plans: From ~$10/month for unlimited clients and additional features.
For most freelancers, the hosted free tier of Invoice Ninja is the practical starting point before deciding whether to self-host or upgrade.
Crater
Crater is a newer open source invoicing application built on Laravel (PHP) with a Vue.js frontend. It’s cleaner visually than older Invoice Ninja versions and is gaining momentum.
Features:
- Invoices and estimates (quotes)
- Expenses
- Reports
- Payment recording
- Multi-currency
Self-hosted: Free. Requires PHP 7.4+, Composer, and a database.
Hosted version: Crater offers a cloud version with a free trial and paid plans.
Crater is a good choice if you prefer a more modern UI and are comfortable with a Laravel stack. It’s not as feature-complete as Invoice Ninja but covers the core quoting and invoicing workflow.
ERPNext
ERPNext is a full open source ERP system that includes a quoting module as part of a much larger suite: CRM, accounting, HR, inventory, and project management.
Relevant for freelancers: Not typically. ERPNext is designed for small-to-medium businesses with multiple departments. The quoting module works, but the overhead of running a full ERP for quote generation alone is significant.
Worth considering only if you’re running a small agency with multiple staff and want an integrated back-office system.
The real cost of self-hosted open source software isn’t the license fee—it’s the time spent on setup, updates, backups, and debugging. Calculate that time honestly before assuming self-hosting saves money.
Who open source quotation software actually serves
It’s a good fit if you:
- Have technical skills and enjoy setting up your own infrastructure
- Have data privacy requirements that make SaaS hosting unacceptable
- Want total control over your data and features
- Are comfortable with community-based support instead of live help
- Are building a small agency with a developer on staff
It’s probably not the right fit if you:
- Primarily want to avoid paying for software
- Don’t have server administration experience
- Value reliable support when something breaks
- Want proposal tracking (open/view analytics) or advanced e-signature workflows
The hidden costs of self-hosting
Running your own Invoice Ninja or Crater instance means:
- Server costs: A basic VPS (Vultr, DigitalOcean, Linode) runs $5–$12/month. This eliminates the “free” advantage compared to paid SaaS tools at similar price points.
- Maintenance time: Framework updates, security patches, and occasional debugging are recurring tasks. Budget a few hours per year at minimum.
- Backup responsibility: If your server goes down and you don’t have backups, your quote history is gone.
- No official support: Forums and GitHub issues are your options when something breaks.
For freelancers who code or have a technical background, this trade-off often makes sense. For everyone else, the overhead frequently exceeds what a $12–$15/month SaaS subscription would cost.
Alternatives to open source for cost-conscious freelancers
If the goal is to avoid significant monthly costs while getting a functional quoting workflow, consider:
- Invoice Ninja’s hosted free tier — 20 clients, no server required
- Wave — free accounting with invoicing; no quoting module, but functional for invoices
- Zoho Invoice — free tier for freelancers (one user, up to 1,000 invoices/year)
- Waco3’s entry tier — purpose-built for freelancers with quoting, proposals, and tracking in one place
The freelance-focused SaaS tools tend to have better UX for solo operators and don’t require technical setup, which is worth something when your primary work isn’t software administration.
The bottom line
Open source quotation software is viable, well-maintained, and genuinely useful for the right user. Invoice Ninja’s hosted free tier removes most of the technical barrier and gives you a functional quoting tool at no cost. Self-hosting makes sense if you have the skills and a reason to own your infrastructure.
For the average freelancer who wants to send quotes and get paid without managing servers, a lightweight SaaS tool—at $10–$15/month—typically delivers more value per hour spent.
Ready to send stronger proposals?
Build, send, and track proposals in one place so follow-up is easier.
Start your free trial →
