Salaries in Sweden are discussed in pre-tax, per month terms. Tax is a personal thing — some people are members of the church, which makes their tax higher. In certain contexts (like applying for a mortgage), income is discussed pre-tax, per year. 30k SEK is probably a monthly salary, and 300k SEK is probably a yearly one.

A job offer for a permanent full-time position in Sweden has a decent salary as a rule. It will cause neither starvation nor abundant savings.

Social security in Sweden is very high, it’s hard to be financially ruined by a health issue, for example, and school education is free.

Swedish system favors "two working adults" approach, meaning that "one working adult and one stay-at-home parent" setup might be a strain.

The biggest expense factor is housing; for an immigrant moving to Stockholm without having their employer arrange an apartment the only option is to rent an overpriced sublet (think 12000+ for a modest apartment with one bedroom). In other cities and cases it’s possible to pay 2000 instead.

Average salary in Sweden is around 35000 SEK per month. This article from the Swedish government agency of statistics says that in 2018 the average salary was 34600, with significant variability depending on profession, age, education, and other factors. Statsskuld.se is one of the websites which allows to browse, filter and explore salary statistics for different positions (the link shows some professions from the IT branch).

[added later] For some real life examples (as opposed to generalized statistics which is the focus of this post), see another post from 2021.

Stockholm on Numbeo, the cost-of-living comparison site

Apartments for rent in whole Sweden, filter by clicking on “Hela Sverige v” and selecting the city or län of interest

Prices on food and other stuff in supermarkets, asks for a zip code first; Stockholm is 11x xx, Gothenburg 41x xx, Malmö 21x xx. For the third digit, 2, 3, 4, 6, and 7 mean “regular mail delivery” and should work