n8n
Alternative to Zapier
Free node based Workflow Automation Tool. Easily automate tasks across different services.
Actively maintained
Real momentum
Apache-2.0, Commons-Clause
BSL, SSPL, Elastic 2.0 and Commons Clause exist for one reason: to stop other companies from reselling the project as a managed service. If your business model is "hosted version of X", these licences kill it outright. Internal use is nearly always fine; BSL versions usually convert to Apache-2.0 after a set change date, which is worth checking before you rule a project out.
Source-available is not open source. These licences allow reading and self-hosting but ban you from offering the software as a commercial service to third parties. This dataset tracks 17 Source-available projects (1% of 1665 total), 16 of them actively maintained, led by n8n with 201k stars. Verified against repository metadata as of August 2026; this is engineering guidance, not legal advice.
Running the software inside your own company, without redistributing it, is permitted under every licence family here except undeclared/proprietary code.
This is the failure mode. Either the network clause forces your source open, or the licence bans competing commercial services outright.
Restricted. Either derivative work must be released under the same licence, or the licence explicitly forbids commercialising a fork.
| Project | Category | Stars | Maintenance | Licence |
|---|---|---|---|---|
| n8n | Automation | 201k | Actively maintained | Apache-2.0, Commons-Clause |
| Dify.ai | Software Development | 153k | Actively maintained | Apache-2.0, Commons-Clause |
| ElasticSearch | Search Engines | 78k | Actively maintained | SSPL-1.0 |
| Sentry Self-Hosted | Software Development | 45k | Actively maintained | BUSL-1.1 |
| Outline | Wikis | 40k | Actively maintained | BUSL-1.1 |
| MindsDB | Database Management | 40k | Actively maintained | Elastic-2.0 |
| Directus | Database Management | 37k | Actively maintained | BUSL-1.1 |
| Composio | Software Development | 30k | Actively maintained | Elastic-2.0 |
| Akaunting | Money, Budgeting & Management | 10k | Actively maintained | BUSL-1.1 |
| Invoice Ninja | Money, Budgeting & Management | 10.0k | Actively maintained | Elastic-2.0 |
| Tandoor Recipes | Recipe Management | 8.5k | Actively maintained | MIT, Commons-Clause |
| Cosmos | Self-hosting Solutions | 6.1k | Actively maintained | Apache-2.0, Commons-Clause |
| WorkAdventure | Communication | 5.7k | Actively maintained | AGPL-3.0, Commons-Clause |
| RudderStack | Analytics | 4.5k | Actively maintained | Elastic-2.0 |
| Erxes | Ticketing | 4.1k | Actively maintained | AGPL-3.0, Commons-Clause |
| Forward Email | Communication | 1.7k | Actively maintained | BUSL-1.1, MPL-2.0 |
| Hook0 | Software Development | 15 | Actively maintained | SSPL-1.0 |
Alternative to Zapier
Free node based Workflow Automation Tool. Easily automate tasks across different services.
Software Development
Build, test and deploy LLM applications.
Search Engines
Distributed, RESTful search and analytics engine.
Alternative to DataDog, NewRelic, Monitoring/Observability
Powerful error tracking platform with wide language support and a robust API.
Alternative to Notion
Extensible wiki for your team.
Database Management
AI layer for existing databases that allows you to effortlessly develop, train and deploy state-of-the-art machine learning models using standard queries.
Alternative to Contentful
An Instant App & API for your SQL Database. Directus wraps your new or existing SQL database with a realtime GraphQL+REST API for developers, and an intuitive admin app for non-technical users.
Software Development
Integration platform for AI agents & LLMs with support for 250+ apps and custom tools.
Money, Budgeting & Management
Accounting software designed for small businesses and freelancers.
Alternative to Invoicing
Powerful tool to invoice clients online.
Recipe Management
Django application to manage, tag and search recipes using either built-in models or external storage providers hosting PDFs, Images or other files.
Self-hosting Solutions
Run server applications securely and with built-in privacy features. It acts as a secure gateway to your application, as well as a server manager.
Communication
Virtual office / virtual conference application presented as a 16-bit RPG video game.
Alternative to Segment
Collect, unify, transform, and store your customer data, and route it to a wide range of common, popular marketing, sales, and product tools (alternative to Segment).
Ticketing
Marketing, sales, and customer service platform designed to help businesses attract more engaged customers.
Communication
Privacy-focused encrypted email for everyone. All-in-one alternative to Gmail + Mailchimp + Sendgrid.
Software Development
Webhooks-as-a-service (WaaS) that makes it easy for online products to provide webhooks. Dispatch up to 3,000 events/month with 7 days of history retention for free.
Source-available is not open source. These licences allow reading and self-hosting but ban you from offering the software as a commercial service to third parties. BSL, SSPL, Elastic 2.0 and Commons Clause exist for one reason: to stop other companies from reselling the project as a managed service. If your business model is "hosted version of X", these licences kill it outright. Internal use is nearly always fine; BSL versions usually convert to Apache-2.0 after a set change date, which is worth checking before you rule a project out.
17 of 1665 tracked projects carry a Source-available licence — about 1%. 16 of them show real momentum (commits in most of the last twelve months plus a recent release), so the practical shortlist is smaller than the raw count suggests.
Licence breach is copyright infringement, and the usual consequence is not a lawsuit — it is a failed diligence review. Acquirers and Series A investors run automated licence scans over your dependency tree; an unresolved copyleft or source-available dependency in a closed product either delays the deal or gets priced into it. The cheap fix is choosing correctly at week one.
No. Source-available licences fail the OSI definition because they restrict fields of use. You can read and self-host the code, but you cannot offer it as a competing commercial service. Treat "source-available" as a marketing term, not a licence class.
Licence data comes from repository metadata and can lag a relicensing event. Confirm the LICENSE file in the repository before shipping. This page is engineering guidance, not legal advice.
IdeaProof checks whether your idea is already built, how saturated the category is, and where the remaining wedge sits — in about two minutes.
Validate your idea freeSearch this database by category and by the commercial product you would replace. It covers 1665 projects across 130 categories, each mapped to the paid tool it substitutes. If your category shows a "Crowded" verdict, a maintained free version almost certainly exists and your positioning has to account for it.
No. It means free is your price anchor. Plenty of large companies were built next to a good open-source project — the ones that failed were the ones selling the same job at a price the free tool made indefensible. Find the part of the job the project deliberately does not do, and sell that.
Each category gets a 0–100 score built from three inputs: how many implementations exist, what share of them are still actively maintained, and how far ahead the leading project is compared with the category median. 62+ is Crowded, 38–61 Contested, under 38 Open. 11 categories are Crowded and 88 are Open.