Yes and no?

I am going to speak about Sweden here, as that is what I am (somewhat) familiar with, others can pipe in on Norway and Denmark. (most sources I've read claims that Norway was even more of an outlier than Sweden, while Denmark was slightly more conventional due to it's closer ties with Germany, but I can't really judge that.)

The problem is mainly one of sources, for Sweden we have very little information for the viking era, a few scattered pieces from (chronicles, the occasional letter, etc.) from the 1000-1200 period (roughly) and then more and more from that period on. Our sources are largely A) Chronicles (such as Saxo Grammaticus and others) and B) Law codes. There are obviously other sources but they are scarce, and it's hard to get a decent picture (especially for since civil wars were common, even something like a "definite" King List for Sweden is somewhat difficult to scrape together, especially considering the (seeming) custom of having several co-kings, or different kings ruling different portions of the country) Once the Bjälbo dynasty starts getting royal in the 1200's we get a better idea of how the things were actually run, swedish "feudalism" is considered to have been formalized (although as with most of these things it probably developed piecemal) with Alsnö Stadga ("Stadga" means "Edict" or "Law", basically) from 1280. It was probably written in latin originally but we have swedish translations from the early 1300's. As said, it's hard to say if the things promulgated here were actually in use before, and for how long. Is this just the first preserved letter we have trying to codify these things?

The important concept here is what in modern swedish is termed "frälse", it literally means "saved" (today it's almost always used in a religious context, though it has had a more extensive meaning historically) and signifies someone who has been exempted from taxation. Alsnö Stadga stipulates that "all those who serve on horseback" are to be exempt (from at least some) taxation "whoever they serve". There's soem arguments over what exactly that means, and if that's a new thing or merely an expansion of older rights.

The idea seems to be to ensure a steady supply of mounted knights for the king's armies, and in return offering tax exemptions. The "frälse" (as this means any kind of tax exemption there are a bunch of subcategories, "bergsfrälse" ("mountain-frälse") associated with mining, the spiritual frälse, IE: tax-exempt clergy, but with the term I will be mostly talking about what later tends to be called "secular frälse"; IE: those who do military service in exchange for tax-exemption) would kind of eventually (in the 1400's/1500's) congeal into the Estate of the Nobility (becoming heridatery rather than dependant on direct military service, etc.)

What is... A bit shadowy is that there is clearly a class of "nobility" (sometimes called "Stormän", literally "large/big/great men") already in existence, the rich and powerful with with large estates, possibly private armies (the largest chunk of Alsnö stadga is actually precouppied with nobles roaming around the countryside in huge groups and basically eating peasants out of their houses without paying) This is all further complicated with the relationships between these families, the old royal guards/houscarls/hirds, and so forth. Lots of confusion (as said, bad sources)

What is interesting is that there seems to have been a bit of a military service-taxes cycle, one of the taxes the new knights were exempt from was the ledungslame, a tax that was originally paid in lieu of participation in the old naval defence organization, the ledung.

One thing that seems to be a bit different in Sweden is that fiefs seems to have mostly been for life (or even a set period) rather than heridatery, this was especially the case for the strategic castles (who tended to be the source of a lot of politicking for that reason)

But like most medieval states, Sweden was a mess (and it changed several times, and sometimes in that particularly aggravating "Let's impose a new structure on the country but let's also keep the old one and not tell future historians what the difference is" that medieval states tends to do.

As mentioned the timeline is often hard to keep track of, since often we get institutions in our sources seemingly "fully developed", with no trace of their precursors.

The "traditional" (again it's unclear when it actually shows up, some provinces have been merged and split, etc.) provinces of Sweden (landskap) were distinct units, with at least initially a great deal of autonomy, including separate laws, sometimes separate internal divisions, at least allegedly based on old tribal areas. (again, the historicity of that is disputed, but it was at least believed by contemporaries) what gets funky is that the centre of the swedish monarchy is clearly in Ostrogothia (that's where most of the kings come from, that's where the earliest castles are, that's where monasteries are endowed, etc.) but various laws clearly stipulate that the actual election of the king belongs to the Svei, the denizens of Uppland. The king was, after his election (no, we don't know who actually elected the king, "The big nobles of the realm" seams a decent supposition, but how exactly it happened is unknown) raised on a stone ("Mora sten", it was later taken by the danes during the Kalmar union and disappears from history), and there is also some evidence of commemorative stone tablets being created (we have some of them, they are confusingly known as "Mora stenar", the "stones" of Mora) after this the king was supposed to travel a set route (Eriksgata) throughout some of the provinces, at the border of each one exchanging hostages and recieving homage. (a few sources mentions one possibly apocryphal king, Ragnvald Knaphövde, who refused to exchange the hostages and was promptly killed)

Laws were, as mentioned, different for each province, the law of the Westrogothians were different from that of the Upplanders was different from that of Gotland. (the status of Finland, here meaning "Finland Proper", the southwestern part, hard to say, sometimes it had it's own lawspeaker, but they seem to have used a few different provincial laws, a 1609 attempt to collect the old provicial laws mentions that they intended to print the finnish law as soon as they found some credible copies...)

Sorry for really late response.

 

As FAQs of this subreddit show, it has increasingly become difficult to define what the exact set of ‘feudalism’ in Medieval Europe. S. Bagge, M. H. Gelting, & T. Lindkvist (eds.), Feudalism: New Landscapes of Debate, Turnhout: Brepols, 2011 tried to handle with the problem, but it was apparently difficult to bring different standpoints of the researchers to a coherent conclusion there.

The basic premises in the adaptation of some ‘feudal’ terms from High Medieval Europe into Scandinavian kingdoms are threefold:

• Some loanwords as ‘riddar’ (<Ritter) or ‘len’ (<Lehen) from (Middle High/ Low?) German.
• It did not mean, however, that medieval Scandinavians accept the whole set of the original concept of the word: rather the opposite seemed to be usually the case. To give an example, what ‘len’ meant in Later Medieval Scandinavia was only a temporal lease of the district as well as its royal fortress as castellans that could not inherited to children of the office holder, so should not translated as ‘fief’ (Bagge 2014: 146).
• As for the functionality in general, however, medieval Scandinavian kingship and especially their central administration in the 13th century onwards showed similarities with contemporary royal administration of European Kingdoms like Plantagenet England to some extent.

 

On the other hand, the following two fields of activity of medieval Scandinavian kings can be regarded as somewhat unique:

• Strong Traditions of Regionalism: We can see the highly centralized royal jurisdiction and the strong regionalism live side by side, especially in the area of local government/ secular justice in high medieval Scandinavian kingdoms. While the monarch almost succeeded in monopolizing the secular jurisdiction within his kingdom especially in high medieval Norway, several levels of local court assemblies (things), inherited (at least their names) from the 11th and 12th century, continued to function. Medieval Scandinavian kingdoms constituted of such ‘Law Provinces’ that had originally had their own provincial laws, and such provinces still played important roles in the daily justice as well as the royal ascension ritual, at least some parts in medieval Scandinavia. This woodcut from the 16th century depicts the alleged tradition of Swedish ascension ritual, called ‘Eriksgata’. The 14th century law code of Swedish realm (Magnus Erikssons landslag) stipulates that newly elected king should take a journey around every law province assembly across the kingdom in a certain order to be accepted as a new king, though I personally rather doubt this practice ever observed, [added] at least as prescribed in the law codes in the beginning. I rather consider the clauses just as an expression to pay homage to the tradition of regionalism in different law provinces.
• Leding, conscripted national defense fleets from the farmers: Danish and Norwegian law codes from the High Middle Ages (and also Swedish ones, though they are a bit late as well as not so detailed) have some clauses on the district-based military organizations to provide men as well as ships to the kings. Older studies had tended to date this royal mobilization of the fleets back to the Late Viking Age tradition like the Danish Vikings’ invasion to England in the beginning of the 11th century, but the provenance as well as the real significance of this system has been seriously debated among the scholars. By the end of the 13th century, this conscription of the farmers certainly turned into an annual tax. Instead of the farmers, the kings also now relied on the new nobles, defined by their bond with the king like the oath of fealty as well as the military service to the king.

 

If you wish to know more details, I'll try to summarize the basic outline (so specify the country. Norway is probably the easiest to grasp the figure as well as to find some literatures in English).

 

Selected Reference:

• Bagge, Sverre. Cross & Scepter: The Rise of the Scandinavian Kingdoms from the Vikings to the Reformation. Princeton, NJ: Princeton UP, 2014.

[Edited]: typo fixes. corrects the factual mistake on Eriksgata (thank /u/Arilou_skiff for pointing out!).