The free back office for your software business - that you actually own
Recurring invoices, customers and real double-entry books, behind a full REST API you can automate - free, self-hosted, and yours. No per-seat fees, no vendor lock-in.
Source-available, with open-source modules. Runs on your own machine. Full REST API (OpenAPI 3.1).
Quick answers
Is Celerp free?
Yes. The desktop app is free for business use: no trial, no per-user fee and no limits on companies, users, items or records. The core is source-available and the modules are MIT-licensed.
Does it work offline, and can I self-host it?
Yes. Celerp runs on your own computer and works offline: the core product needs no internet connection. You can also self-host it on an office or cloud server, so the database stays on hardware you control.
What does Celerp cover?
Inventory, invoicing, purchasing, double-entry accounting, CRM, manufacturing with bills of materials, and reporting, all sharing one set of data.
Which industries is it built for?
It ships with presets for retail and e-commerce, jewelry, gemstones, watches, coins, fashion, cosmetics, food and beverage, wine and spirits, agriculture, electronics, auto parts, hardware, furniture, books and media, art, manufacturing, consulting, SaaS and software, and nonprofits, clubs and associations.
What does Celerp Connect cost?
$29 a month or $290 a year for your whole setup, never per user, with a 14-day free trial. Connect adds store and accounting sync, remote access, 100 included AI queries and encrypted cloud backups. The desktop app works fully without it.
Updated for version 2.7.0 on 19 October 2026.
Why software founders run Celerp
Your billing and books shouldn't be a stack of subscriptions you don't control - or a database you can't query.
Recurring invoices, self-hosted
Generate recurring invoices for your plans and seats - weekly to annual, or a custom cadence - in software you host yourself.
Customers & revenue in one ledger
Track who pays what, what's outstanding, and your real revenue - not scattered across five tools.
Books you actually own
Real double-entry accounting, multi-currency, exportable - on your own machine, not a vendor's cloud.
Automate all of it
Every action in Celerp is a REST endpoint (OpenAPI 3.1) - wire it straight into your app and scripts.
Celerp is the layer you own - not a payment processor. It keeps your billing records and books. Card payments run through your own Stripe account, so the money never passes through us. Think of it as the self-hosted billing and accounting layer behind your software business, one you can automate end to end.
Up and running in minutes
Install free
Download the desktop app, or pip install celerp on a server. One command, no account, no credit card.
Set up plans & customers
Add your customers and recurring invoices for your plans and seats - or create them straight from your app via the API.
Automate with the REST API
Every action is an endpoint. Create invoices, read revenue, post entries - wire Celerp into your product and scripts.
Built for builders
A back office that behaves like infrastructure you control.
OpenAPI 3.1 - every UI action is also an endpoint. The same API the app uses.
Recurring invoices on any cadence. Bill due periods yourself, or turn on unattended billing per subscription.
Real double-entry books in any currency, always in balance.
Runs on your machine or server. Your data never leaves it.
Want it to sync to QuickBooks/Xero, run from anywhere, or back up off-site? That's Celerp Connect ($29/mo). The API and self-hosting are free.
Why Celerp fits a software business
The back office of an ERP, with the manners of a dev tool.
- ✓ Free forever - the whole app, no trial
- ✓ Full REST API (OpenAPI 3.1)
- ✓ Recurring invoices for plans & seats
- ✓ MRR, ARR, churn and cohorts from your real invoices
- ✓ Real double-entry accounting
- ✓ Free trials, and seat changes billed pro rata
- ✓ Multi-currency
- ✓ Self-hosted - desktop or your own server
- ✓ Source-available, no vendor lock-in
- ✓ Add your whole team - no per-user fee
- ✓ Card payments through your own Stripe account, with saved cards and retries
- ✓ Annual plans recognized month by month
Free to start. Cheap to grow.
The whole app - and the full API - are free. Add Connect only when you want sync, remote access or backups.
The complete app and the full REST API - recurring invoicing, customers and accounting. No account, no trial, no per-user fee.
- ✓ Full REST API (OpenAPI 3.1)
- ✓ Recurring invoicing & accounting
- ✓ Self-hosted - desktop or server
- ✓ Your data stays yours
Sync to your accountant's tools, reach it from anywhere, and back it up.
- ✓ Everything in Free
- ✓ Sync to QuickBooks & Xero
- ✓ Use it from any device, anywhere
- ✓ Automatic encrypted backups
- ✓ AI helper for the boring stuff
14-day free trial. Cancel anytime.
Questions software founders ask
Is it really free?
Yes - the whole app, including the full REST API, recurring invoicing and accounting, is free forever with no per-user fee. Optional Connect features (accounting sync, remote access, AI, backups) are a low monthly add-on.
Does it charge my customers' cards?
Celerp is not a payment processor. Connect your own Stripe account and each invoice gets a pay link. With your customer's consent, a saved card can also be charged when an invoice falls due, with retries if a charge fails. The money goes straight to your Stripe account.
How good is the API?
Every action in the app is a REST endpoint, documented as OpenAPI 3.1 - the same API the UI uses. Fetch the schema from your own copy and generate a typed client in your language.
Can I self-host and own my data?
Yes. Run it on your own machine or server; your data never leaves it. It's source-available with no vendor lock-in.
Can it do recurring billing?
Yes. Bill plans and seats on any cadence, from weekly to annual or custom, with free trials, seat changes billed pro rata, and cancellation at the end of a period.
Own your back office
Download Celerp, or read the API guide and wire it into your stack.
Free forever. No account, no credit card.