SCF #8
Stellar PHP SDK

Easy access to Stellar for PHP developers

Budget request:

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Products & Services

Core functionality
This part of the SDK will provide API's to build and sign stellar transactions (such as for example payments or offers) and commit them to Horizon. Furthermore it will provide functionality to query all available Horizon API's.

Implementation of multiple Stellar Ecosystem Proposals (SEPs) :
- SEP-001: Querying and parsing of Stellar Info Files
- SEP-002: Federation Protocol (Handling requests and responses of federation servers)
- SEP-005: Key Derivation Methods for Stellar Keys (mnemonic codes)
- SEP-006: Deposit and Withdrawal API (Anchor/Client interoperability)
- SEP-007: URI Scheme to facilitate delegated signing
- SEP-009: Standard KYC Fields
- SEP-010: Stellar Web Authentication
- SEP-011: Txrep (human-readable low-level representation of Stellar transactions)
- SEP-012: KYC API
- SEP-023: Muxed Account Strkeys
- SEP-029: Account Memo Requirements

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Previous Project(s)
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Progress so far

Our next step is to implement the PHP SDK core functionality including SEP-029.

To get there, we request a budget of  

Oct 2021 – March 2022

- Implement Core Functionality including SEP-029
- SDK Promotion / Awareness
- Salary of 1,5 team members: 114,000 USD

April – August 2022
- Implementation of SEP-001, SEP-002, SEP-023, SEP-005, SEP-010, SEP-007, SEP-009, SEP-006, SEP-012, SEP-011
- SDK Promotion / Awareness
- Salary of 1,5 team members: 95,000 USD

Sept – Dec 2022
- SDK Maintainance
- SDK Promotion / Awareness
- Salary of 1,5 team members: 16,000 USD

Additional information

Problem & Solution

- The existing PHP SDK for Stellar is not maintained since 2018. It's owner and maintainer is not reachable any more. See github repository:
- As we see from packagist there is a very high demand for a php sdk. Furthermore php is a popular programming language and is used in many projects. Therefore the new sdk will bring additional php developer to Stellar and increase popularity of Stellar.
- We are the maintainers of the award winning iOS Stellar SDK since 2018 and of Flutter Stelllar SDK since 2020.

Our Mission
- We will create a new open source SDK which will be up to date with the newest Stellar Core Protocol Versions (currently version 17) and will implement several Stellar Ecosystem Proposals (SEPs).
- The maintainace of the SDK for one additional year is also included in the requested budget.
- For the future maintance of our new stellar php sdk, our goal is to receive support from the Stellar infrasctructure grand committee.

Our proposal is aligned with the following Stellar Network Goal:
The Stellar Network should make it easy for developers of Stellar projects to create highly usable products

Target Market

More than 5 Mio  PHP developers who need to interact with the Stellar Network for their projects.
79% of all websites use PHP as the server side language.

Revenue Model

As our product will be open source to enable PHP applications there is no selling approach of the product.
Nevertheless we see the following fundings to add on top of the SDK funds.

- Maintanence budget from the stellar infrastructure grant.
- Consulting
- Donations

Marketing Research

Size and Trend
- More than 5 Mio PHP developer estimated.
- most popular PHP applications: Facebook, Wordpress, Wikipedia, Flickr
- based on the percentage of a high 79% usage of PHP with the server side languages stays stable

Target Market
- our goal is to enable the PHP developer to use our SDK to build Stellar applicatiosn and APIs to enhance the functionality of existing and future PHP applications.
- we will actively communicate with the PHP community and propose the use of our SDK

Threats and Opportunities

The usage of PHP is on a stable high level with 79% within the Server Side Languages.
It is unlikely this will change within the next years. So within the next 10 years PHP will most likely stay a relevant language.


The only competitor is the existing Stellar PHP SDK (owner zulucrypto).
But this SDK is outdated since 2018 and misses many updates with the core functions as well the implementation of all SEPs, except SEP-005.

Marketing and Sales

We will address the following marketing and promotion activities:

- Creating general content/tutorials on youtube, , ...
- on Stellar channels like reddit,, discord, keybase, ...
- on PHP forums like,, and others

We will support by solving all issues posted on github and also do consulting if needed.

As our main goal is enable PHP developer to create Stellar applications by providing an up to date SDK.
We will provide maintainance on the SDK until end of 2022. After that our goal is to receive support
from the Stellar infrasctructure grand committee to be able to continue with maintainance.

We also will do consulting on the usage of the SDK and how to implement Stellar functions in PHP projects.

Resources and Relationships

We are in touch with Stellar PHP projects like Coinqvest and will interact with the PHP community and developers
to enable an easy way to build PHP applications on Stellar.

BlueOrion also will use the new SDK to update the applications accordingly.

Pitch deck
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First Deliverable

In the next stage we will provide an updated PHP SDk with the Core Functions of Stellar Protocol Version 17.
The SDK will be available in March 2022 and then can be used by the PHP community.

This is the underlying step to then implement the SEPs listed above, so PHP development will be even easier.


Hans Woppmann - CEO of
- Full Stack Developer with a Masters Degree in Computer Science
- Active within the crypto space since 2013
- Development of Stellar projects since 2017
- Winner of three Stellar funds
- Organizer of Stellar meetups and workshops
- Speaker at Meridian the first Stellar Conference 2019 in Mexico  

Christian Rogobete - Owner of Soneso GmbH
- Full Stack Developer and Product Owner with a Masters Degree in Computer Science
- Active within the crypto space since 2016
- Development and maintanance of the Stellar iOS SDK since 2018 and of the Stellar Flutter SDK since 2020
- Multiple contributions to the stellar protocol github repository
- Winner of the Stellar Build Challenge with the Stellar iOS SDK

About the companies

This project will be carried out by Christian Rogobete ( and Hans Woppmann (
Both companies have carried out several Stellar projects.

Soneso GmbH (
- Stellar iOS SDK
- Stellar Flutter SDK - Projects
- Non-Custidoan-Wallet to enable Timed Payments
- Organizer of Stellar Community Meetings and workshops in Germany
- Stellar Voting Platform

This project will be handed in, in the name of Soneso GmbH (