Sins of a Solar Empire II: Ship counters chart

If you are new to this game this section is all you need to know for start, other sections are for nerds/pro gamers who want to know everything about all the matchups.
Kanrak and Javelis are gauss frigate variants with same counters.
Tempest frigate has 360 firing arc while gauss frigate has only small front facing firing arc, that is why Tempest frigates can counter light frigates and Gauss frigates if microed to close in on them and run circles around them at close range.
Gauss/light frigate player can counter this by spreading out his frigates that way they can allways target atleast some tempests.
Tempest like any other missile ship can be countered by “any mainline ship+ship with PD guns”combination(more on this in mainline ship variants).
Exoria Illuminator and Vigilis Sentinel are Heavy cruiser variants with similar counters.(more in Variants of Mainline ships)
Capital ship spam has same counters as heavy cruiser spam.(more on this in Capital ship counters section)

Mainline ships are ships that are cost effective in straight up fight and that is why they should comprise majority of your fleet.
Carriers lose in straight up fight against any mainline ship fleet of equal resource cost, that is why they are not mainline ship but support ship great in sieges both as defender and as attacker.

TIER01

GUN CORVETTE(tec corvette,advent corvette,vasari defensor corvette)
equal trade
vasari carrier with PD
vasari PD scout(with equal resources, PD scout loses with equal supply

Counters anything it is not countered by

countered by
heavy cruiser
tempest frigate
weakest mainline ship to aoe
capital ships with aoe

LIGHT FRIGATE
equal trade
tempest frigate
capital ships

Counters anything it is not countered by

countered by
corvette
heavy cruiser
second weakest mainline ship to aoe

TEMPEST FRIGATE
equal trade
light frigate
gaus frigate
flak frigate(without support)

Counters anything it is not countered by

countered by
heavy cruiser
capital ships
any mainline ship + atleast 50% of army in PD ships(harder to counter with PD ships than other missile ships due to double number of missiles)

TIER02

GAUS FRIGATE
Equal trade
Tempest frigate

Counters anything it is not countered by

Countered by
Light frigate
Corvette

TIER03

HEAVY CRUISER

equal trade
capital ships

Counters anything it is not countered by
+Strongest Mainline ship against AOE

countered by
missile frigate/cruiser
gauss frigate
weakest mainline ship to mind control

ADVENT BEAM CRUISER
same counters as heavy cruiser except
counters capitals
countered by light frigate

ADVENT PD CRUISER
Counters missile frigate/cruiser,tempest frigate, corvettes, light frigates, strikecraft
Countered by
Everything else

MISSILE FRIGATE/CRUISER
better stats but fills the same role as gaus frigate with one extra counter: PD gun unit + any mainline ship
list of PD gun units sorted from best resources to PD gun ratio ships to worst ratio resources to PD gun ship
vasari scout(best cost efectivnes per PD gun DPS mitigated by poor supply efectivness)
advent PD cruiser
vasari carrier
tec flak frigate
vasari gun corvette
vasari heavy cruiser
carrier capital ship

HARDEST COUNTER TO MISSILE BASED ARMIES:
advent carrier capital and TEC tech02 item for capital ships flak burst can keep destroing all misiles on the field for more than 10 sec each these can make missile based armies useless when massed

VASARI MISSILE CORVETTE
good vs buildings(except autocannon turrets) and ships that cannot hit it(light frigate,gaus frigate,missile frigate)
bad vs everything else

CARRIER
good when used at long range hidden behind turrets or sieging enemy turrets
not cost effective at straight up fight against any mainline ship(even with full bombers against heavy mainline ship or full fighters against corvette)
weak to mind control spells and items
The best unit against AOE damage spells
soft countered by any mainline ship
hard countered by any mainline ship+PD ships

ADVENT CARRIER
has supperior bombers with beams that cannot be shot down with PD ships like missiles from other bombers

VASARI CARRIER WITH PD
has powerfull PD guns but overrall less bombers than other carriers when they are armed with just bombers
equal trade vs corvette in straight up fight, rest of the matchups are same
counters any missile ships

OGROV TORPEDO CRUISER/VASARI PENETRATOR
good against buildings and titans
Countered by
Everything else

DESTRA CRUSADER
beter than its counterparts and cheaper
good against buildings, capital ships and titans
Countered by
Everything else

these ships are so dedicated to support role that they cannot attack just support other ships,
allways avoid making these ships majority of your army since your enemy will just focus fire your ships that can deal damage and then your fleet id left defenseless.

ICONUS CRUISER
the best dedicated support ship from all races, sooner or latter should be added into almost every fleet.
greatly helps survivability of your capital ships.

DOMINA CRUISER
cannot stun capital ships,
can be usefull to include a few in your fleet against carriers,Turrets,Hangars and heavy cruisers.

HOSHIKO ROBOTICS CRUISER
not as powerfull burst healing for capital ship survivability as tech02 or higher defensive items.
great sustained healing for entire fleet for long fights or fights that take breaks by one fleet retreating.
when it gets tech03 upgrade these have great synergy with capital ships that have short cooldowns which are
Kol Battleship with Experimental Beam
Dunov Battlecruiser with Shield Recharge
Ragnarov Titan with Snipe
Ankylion Titan with Shield Recharge

SEREVUN OVERSEER
+great out of combat for mobile Phase Detection.
-it is really expensive for how much damage it can take that is why it should almost never be taken into combat because your opponent will focus fire it
only use in combat against opponents that don’t know what target priority means.

these general rules apply(but there are exceptions):
if enemy is building gauss frigates or other anti capital ships, make tank capital ship and/or buy defensive capital ship items.
if enemy is not building gauss frigates or other anti capital ships make proactive capital ships and/or buy ofensive capital ship items.

TANK CAPITAL SHIPS
kol battleship
kortul devastator
advent have no capital ship with exceptional survivability instead they depend on Iconus cruisers and Progenitor Mothership for capital ship survivability

PROACTIVE CAPITAL SHIPS
Marza Dreadnought(damage dealer)
Vulkoras Desolator(single target DMG)
Jarrasul Evacuator(AOE dmg DOT)

ADVENT CAPITAL SHIPS:
all of them are similar in tankyness and proactivity and have synergy with each other that is why making one of each is ussualy better than massing just one type:

Rapture battlecruiser can give damage reflect on Radiance Battleship which can taunt enemies on itself and Progenitor mothership can heal Radiance Battleship to help it survive,
and just one or two Halcyon Carrier capitals can drasticaly reduce enemy fleet missile DPS.

Radiance Battleship(Taunt, best against fleets that dont have gauss frigates or other anti-capital ships)
Rapture Battlecruiser(has damage reflect which alone is good against gauss frigate or other anti-capital ship heavy army)
Progenitor Mothership(AOE shield heal,great synergy with Iconus)

CARRIER CAPITAL SHIPS:
all have lot of PD making them good against missiles and strikecraft
all have a lot of strikecraft making them good at long range sieges and giving them decent DPS

UTILITY CAPITAL SHIPS:
(they are weak in straight up combat, only use them if you know what you are doing)

Akkan Battlecruiser gives extra income that has dimminishing returns with more Akkans, has attackspeed aura for entire fleet that does not stack,
has powerfull ultimate that dissables attack of friend and foe for a whole minute allowing your entire fleet to dissengage from lost fight without losing units while running

Antorak Maurader can phase out target ship allowing you to cancel channelling of powerfull ultimates like Marza Missile barrage or Akkan Armistice or Radiance beam
Dunov Batlecruiser can destroy antimattter of enemy titan and restore shields of friendly titan(can also do this for capital ships but just for that this ship is ussually not worth it)
Revelation Battlecruiser is only advent capital ship without synergy, it is just anti building and anti planet capital ship

ITEMS FOR CAPITAL SHIPS:
it is ussualy better to have one capital ship that has items than two capital ships that dont have any items
because one capital ship with damage items can roughly deal same damage as two capital ships, or one capital ship with defense items has roughly same efective HP as two capital ships without them,(this statement takes atleast tech02 items into account)
difference is one capital ship with items gets to higher lvl faster than two capital ships,
also one capital ship with defensive items is much better against focused fire than when efective hp is divided between more two low lvl capital ships

Notable Items
Radiation Bomb
powerfull counter against mass corvettes, ok against mass light frigates if opponent does not split them.
Flak Burst
keeps destroying every missile around your capital ship for 15 seconds which, also damages strikecraft around your capital ship.
Tech02 defensive items:all sides have tech at tier02 that unlocks item that greatly increases capital ship survivability