Blockchain is a distributed database that allows direct peer-to-peer transactions without a central authority. All transactions are organized into blocks, and blocks are linked into a chain. Each block in the chain contains information (a hash) about the block that comes before it in the sequence. The classic blockchain network consists of equal nodes, where each node stores a complete copy of the whole chain and so the whole log of transactions, stored in blocks, is replicated many times. What differentiates blockchain from other methods of storing information is that it is decentralized. Rather than having a central database of transactions, it relies on multiple copies of the transactions data, replicated in the network of nodes. The decentralized nature of blockchain makes it more difficult to corrupt the entire system as it is necessary to introduce a fake transaction into every copy of the chain stored on the network. For a more in-depth overview of what is blockchain, check this article: All You Need to Know About Public & Private Blockchains

QA engineers play an important role in all stages of the software development process. At the initial stage, when there is just a basic idea of the future product, QA engineer can help collect all the details and figure out all nuances of the application. Based on gathered info, they create user stories. QA engineer's goal here is to check the compliance of customer's ideas with their possible realization and to set terms that will be clear to every team member. QA engineers help to make customer requirements clear for developers by interpreting them into user stories. After user story is created, QA can set its severity, so the team can see that any changes in that part of an application can heavily change or affect other parts in some way. They save developer's time by doing that. QA engineers also write documentation that puts together all knowledge, rules and ideas of the software project. Its scope may vary from a simple checklist to a pack of test suites with dozens of test cases. This also saves a bunch of time and gives a better knowledge of the project to the team. There are different types of tests that can be performed by QA engineers, such as: Automated and manual testing, Functional and regression testing, Load and stress testing, Usability testing, Compatibility testing. Then QA engineers write bug reports - the list of the things that went wrong with a full description of the detected glitches, e.g. location of a bug, steps needed to reproduce it, results of the error and estimated results after fixing it, etc. Here is a more in-depth description of QA responsibilities in the software development company: QA Engineers: What Are They Doing?

There are some signs that help to differentiate between the professional developers and amateurs. In fact, being a good coder doesn't necessary mean being a great developer for a startup, especially if founders of a startup are not tech savvy people. The development camp should also have good communication skills and understand the business side of the project. The capability of developers to perform the technical part of development can be determined from reviewing their past projects. The rest, can be evaluated by asking the developers how the development process is generally organized, how their activities can be tracked and what responsibilities they can handle. While discussing all these, the project owner will also see if everything is fine with the communication and mutual understanding. Another good way is to ask for references and ask founders of some previously developed projects about their experience with this development team.

Rails is the framework which we use in most of our projects and, according to our experience, React and Rails work well together.