A Schengen visa means entry to twenty-nine countries on one visa, but you cannot make the application to whichever embassy you like. The rule is precise, and someone who does not know it either books an appointment for nothing or runs into trouble at the border. On top of that the choice of embassy affects the waiting time and the chance of refusal. Below I have written the rule and the practical details.
Which country to make a Schengen application to
The main rule is this: the application is made to the country of your main destination. The main destination is the country where you spend the most nights. If you stay five nights in Italy and two in France, you apply to the Italian embassy.
If the number of nights is equal, the second rule comes into play and the application is made to the country you enter first. If you stay three nights in Germany and three in Austria and land in Germany first, the German embassy is the right address.

Countries with no embassy for a Schengen application
Not all the Schengen countries have an embassy in Baku. In such cases a system of representation works, that is, one country accepts applications on another’s behalf. France plays that role for Portugal, and another country does for Malta.
For some countries, though, you have to travel to a third city such as Ankara or Moscow. That means extra cost and time, so take it into account when building the route. The representation list changes, so check it before applying.
What the choice of embassy affects in a Schengen application
| Appointment wait | Up to two months at some embassies in the summer months |
| Document list | The general rules are the same, the details differ |
| Processing time | 15 days as standard, sometimes stretching to 45 |
| The period granted | Some embassies issue a long-term visa on a first application |
Changing the route deliberately to apply to a more comfortable embassy is a risky route. If the entry stamp at the border does not match the country that issued the visa, questions can be asked. The most correct route is to build the itinerary realistically and choose the embassy the rule points to.
If the route changes after the visa is issued
A change of plan after the visa is issued is not a breach of the law. A Schengen visa is valid throughout the zone and you can go to whichever country you like. What matters is that your intention was real at the moment of application.
But making the first entry through the country that issued the visa is more comfortable where possible, especially if it is your first Schengen visa. To choose the flight options accordingly, look at flight prices by destination. The official rules are published in the European Commission’s visa section.
In summary
A Schengen application is made to the country where you spend the most nights, and in a tie to the country of first entry. Check the representation list, take the appointment wait into account, do not change the route artificially. To choose the country of application together, fill in the application form.
Note: representation and appointment rules can change, so check the embassy’s site before applying.