# Open Source Referral System for Mobile Apps: What Exists

> What a self-built or open source referral system for a mobile app needs, which open source projects exist, and how build cost compares with a hosted service.

_Last updated: 2026-10-26_

There is no single open source referral system for mobile apps. There are open source pieces: self-hosted deferred deep linking, web referral and affiliate systems, and SDKs, which you join with your own backend and reward code. This guide lists what a system needs, what exists on GitHub, and what building it yourself costs.

Facts about the projects below were read from their GitHub pages on 2026-10-26. Stars and licenses change, so check the repository before you commit.

## What a referral system needs

Whether you build or adopt, a mobile referral system has the same four layers, plus your own rules.

1. **A link service.** Each user needs a unique link that resolves quickly, works on iOS and Android, and records taps. It must send people without the app to the right store.
2. **Store-install survival.** The app store install drops the context of the tap. On Android the Google Play install referrer carries a value through the install. On iPhone you need a handoff such as the clipboard or a paste step, or a probabilistic match. See [make a referral link survive the App Store](https://warplink.app/blog/ios-referral-link-after-install).
3. **Attribution.** Connect the new install to the link that produced it, record how sure the match is, and give each installer one credit. [Exact vs estimated attribution](https://warplink.app/blog/referral-attribution-exact-vs-estimated) explains why that confidence matters for rewards.
4. **A webhook or callback.** Your backend must learn about the credit in a form it can trust: signed, retried, and safe to receive twice. [The webhook receiver guide](https://warplink.app/blog/referral-reward-webhook-node) shows the receiving side.
5. **Your rules on top.** Reward choice, caps, delay until a real action, and abuse checks. These are always yours, whatever you use below them. See [preventing referral fraud](https://warplink.app/blog/prevent-referral-fraud-mobile-app).

## Open source projects worth knowing

Each entry is what the project describes about itself, with license and stars on 2026-10-26.

### Self-hosted deferred deep linking

- **[LinkForty/core](https://github.com/LinkForty/core)** (AGPL-3.0, 47 stars). A self-hosted deep linking engine with deferred deep linking. It covers the link and store-handoff layers, so the reward logic stays yours.
- **[Newtdev/blynk-deferlink](https://github.com/Newtdev/blynk-deferlink)** (MIT, 5 stars). Self-hosted deferred deep linking and referral attribution for React Native, with PHP and Node backends, the Android Install Referrer, and an iOS clipboard handoff.
- **[grovs-io/grovs-iOS](https://github.com/grovs-io/grovs-iOS)** (MIT, 5 stars). An open source deep linking and attribution SDK for iOS that supports self-hosting.

### Referral and affiliate software

- **[amicalhq/refref](https://github.com/amicalhq/refref)** (AGPL-3.0, 239 stars). A referral and affiliate system. Its README describes it as alpha, and it is a web product, so mobile install handoff is work you add.
- **[Refferq/Refferq](https://github.com/Refferq/Refferq)** (MIT, 132 stars). A Next.js affiliate system. It manages affiliates and payouts on the web side.

The split is useful. The deep linking projects cover the layers a mobile referral depends on, and the referral systems cover the program side for the web. Joining the two is yours to build.

## How to choose a license

AGPL-3.0 projects can require you to publish your changes if users interact with the software over a network. For a backend service you run for your own app, that matters. MIT projects carry no such condition. Read the license text against how you plan to run the code, and ask a lawyer if the project is core to your business.

## What building it costs

The first version is smaller than people expect. The upkeep is larger.

| Work | First build | Continues after launch |
|------|-------------|------------------------|
| Link service and redirects | Days | Uptime, scale, abuse handling |
| Play install referrer | Days | API changes |
| iPhone handoff | Weeks to get right | Every iOS release |
| Attribution and one credit per installer | Days | Edge cases as they appear |
| Signed webhook with retries | Days | Delivery monitoring |
| Testing on real devices | Days | Each store and OS change |

Count the continuing column, not just the first. A referral program that breaks quietly after an OS release costs you in lost rewards and lost trust, and you may not notice until users complain.

A fair rule: build when the referral logic is your product, or when you must keep every byte on your own servers. Use a hosted service when referrals are a feature of something else. For the full comparison, see [the best ways to add a referral program to a mobile app](https://warplink.app/blog/best-ways-to-add-a-referral-program-to-a-mobile-app), and [the indie playbook](https://warplink.app/blog/referral-program-for-indie-apps) for the cost side.

## Where WarpLink fits

The WarpLink SDKs for iOS, Android, React Native, and Flutter are MIT licensed and open source, and the repositories are public under the WarpLinkApp organization on GitHub:

- [warplink-ios-sdk](https://github.com/WarpLinkApp/warplink-ios-sdk)
- [warplink-android-sdk](https://github.com/WarpLinkApp/warplink-android-sdk)
- [warplink-react-native-sdk](https://github.com/WarpLinkApp/warplink-react-native-sdk)
- [warplink-flutter-sdk](https://github.com/WarpLinkApp/warplink-flutter-sdk)

You can read every line that runs inside your app. The link, attribution, and analytics service behind them is hosted, which is what removes the upkeep column above. It sends a signed `referral.claimed` event to your backend, and the reward stays your code. [The referrals guide](https://warplink.app/docs/guides/referrals) has the full flow.

## Frequently Asked Questions

### Is there an open source referral system for mobile apps?

There are open source pieces, not one complete system. Some projects cover the web side of referrals and affiliates, and some cover self-hosted deferred deep linking for apps. You join them with your own backend and reward code.

### What does a self-built referral system need?

A link service, a way for the invitation to survive the store install, install attribution, and a webhook or callback to your reward code. The reward rules, caps, and abuse checks are on top of that.

### Is WarpLink open source?

The SDKs are. The iOS, Android, React Native, and Flutter SDKs are MIT licensed and public under the WarpLinkApp organization on GitHub. The link, attribution, and analytics service is hosted.

### What licenses should I check before self-hosting?

Read each project's license. Some are MIT, and some are AGPL-3.0, which can require you to publish changes if you offer the software over a network. Check it against how you plan to run the code.

### Is building it myself cheaper than a hosted service?

Only if your time is free. The code is a few weeks of work, but the store-install handoff, device testing, uptime, and upkeep with each OS release continue after launch. A hosted free plan costs nothing to start.

## Related Guides

- **Reference:** [Referrals](https://warplink.app/docs/guides/referrals) and [SDKs](https://warplink.app/docs/sdks).
- **Choosing:** [Best ways to add a referral program to a mobile app](https://warplink.app/blog/best-ways-to-add-a-referral-program-to-a-mobile-app) and [referral code vs referral link](https://warplink.app/blog/referral-code-vs-referral-link).
- **Build it:** [Build an invite friends feature](https://warplink.app/blog/invite-friends-feature-mobile-app).
- **Small teams:** [Referral program for indie apps](https://warplink.app/blog/referral-program-for-indie-apps).
- **Use case:** [App referral programs](https://warplink.app/use-cases/app-referral-programs).

## How WarpLink Helps

We run the parts that are slow to build and slow to keep working: the link service, the invitation that survives the store, install attribution, and the signed event. The SDKs in your app are open source under the MIT license, so you can read and audit them.

One workflow, three pillars. Deep linking carries the invitation, install attribution credits the link that produced the new user, and real-time analytics shows referrals beside every other link. Sub-10ms redirects on the way in, one SDK on the way out.

[Create a free WarpLink account](https://dash.warplink.app/auth/signup) and get deep linking, install attribution, and real-time analytics in one SDK, with 10,000 clicks a month on the free plan.