The Engineer is a unique class due to his ability to construct buildings. He can get his teammates to the front lines faster with Teleporters, create a powerful Sentry Gun to ward off enemies, and can build Dispensers to heal and supply ammunition to his teammates. The Engineer's low Health and average speed make it important for him to rely on his Sentry Gun, other buildings, and his teammates for protection. While his ways can seem somewhat passive and methodical, Engineers are not to be underestimated. A talented Engineer can make it much easier for his team to hold its ground, keep up the pressure on the attack, and defend vital objectives such as control points and Intelligence.
Shotgun or Panic Attack
Pistol or Short Circuit
Wrench or Southern Hospitality
For a purely defensive Engineer. This combination allows the Engineer to hold positions against attack, albeit with high cost in Metal and upgrade time. The Short Circuit and Pistol provides defense against rockets and explosives (the greatest bane of a Sentry Gun), although it increases the Engineer's reliance on having a functioning, upgraded, and well-placed Dispenser. The weak damage of the Short Circuit can leave you open to other attacks, such as Spies and flank attacks. The Pistol by comparison is a great weapon for attacking enemies from long range, along with the increase of ammo for defending the buildings. Nonetheless, as the sentry is free to fire on its own and won't be disabled by the Wrangler, this combination allows the defensive Engineer to be a bit more independent.
This weapon set will allow you to preserve your Sentry Gun as long as possible and use the Shotgun to weaken foes or kill any Spies in range, or use the Panic Attack as a means to quickly confront a lone threat to any of your buildings and use it in conjunction with Sentry Gun fire to deal additional damage in a short burst, which can come in a handy if an enemy has a Medic providing Overheal. The Southern Hospitality provides excellent defense against Spies and prevents them from escaping via invisibility, however your weakness to fire can make any sort of offensive pushing much more risky; if there is a great number of Pyros on the other team, and constantly ambushing your buildings, try using the Wrench over the Southern Hospitality.
Frontier Justice or Widowmaker
Pistol
Jag
For an advanced supportive Engineer. This set allows you to deploy your buildings quickly with the 30% faster construction rate granted by the Jag. This may give you more time to walk around and help maintain the buildings of other Engineers. The Revenge crits will become useful if your sentry happens to be destroyed. The Widowmaker is a great weapon if you don't need time to reload and drop the enemies health. The Pistol provides an alternative firearm and is great for conserving your Revenge Crits or not use metal if you used the Widowmaker. You can freely use the Wrangler instead for long-range offense with your sentry to keep your opponents at bay, though this will distract you from your and other Engineers' buildings.
Shotgun
Wrangler
Jag
This combination is similar to the advanced supportive Engineer set but there are small changes. You can use your Wrangler to dispatch Snipers quickly and weaken enemies at a long distance. But having no bonus health means you are more likely to die.
This can also be a good loadout for an Engineer who likes to try and build behind the enemy lines. The Jag helps build up the base more quickly and the Wrangler can help the Engineer build in some unusual locations and immediately attack foes with the enhanced firepower.
Frontier Justice or Widowmaker or Panic Attack
Pistol
Gunslinger
This set is for an assault-oriented Engineer who doesn't want to camp in the enemy base for the whole battle and get out and fight. The Gunslinger paired up with the Frontier Justice gives you many stored crits because the combat mini-sentry is very weak and will get destroyed often. Alternatively, the Widowmaker can be used at close range to replenish your metal quickly. In addition, the Panic Attack's increased damage at closer ranges, in addition to the fixed spread giving greater consistency can be deadly at closer ranges, allowing for over 100+ damage in one shot. The Pistol also gives you the upper hand when fighting from a distance, and you can also use it to finish off enemies weakened by a revenge crit. The extra 25 health from the Gunslinger gives you extra fighting time and the ability to take more damage. You can also place your mini-sentry to give you some more firepower in a battle.
But this set is sometimes risky when going against classes that have a larger amount of firepower than you do, such as soldiers. An Engineer using these weapons can be used for support, as he can be effective when he sticks by his teammates and helps them out with his revenge crits and mini-sentry. You still pack a punch in most battles, think before you whip out your mini-sentry, as sometimes enemies will have much more firepower than you do. If so, plant you mini-sentry and retreat before they can catch you.
Frontier Justice
Wrangler
Gunslinger
This is another assault oriented setup, however this gives you a range advantage with a wrangled Mini Sentry and allows you to get more revenge crits from said wrangled Sentry Gun. Wrangled sentry kills still count as kills that can go towards your revenge crits so using your Wrangler a lot can benefit you in good areas. For the most part, if you get at a distance from an enemy attacking your mini you can pump rounds into him by firing your sentry at him where 1 of 3 things will happen, either he will destroy your sentry without it having kills where you can simply run away, he'll destroy it with kills on it and you can mow him down with revenge crits, or you'll just get another sentry kill. With this setup, you can hold down offensive lines very well, but be careful of Heavys or Medic combos as they will have little trouble with you and your Sentry Gun.
Widowmaker
Short Circuit
Wrench or Gunslinger
This set will eat up your metal very quickly. Enough misplaced shots from the Widowmaker will render you useless, and force you to replenish your metal. These weapons are best used after you've already constructed your Sentry Gun and Dispenser. This way, you still have other means of survival, and the Dispenser can replenish any metal you lose with missed or poor shots. You can also use the Short Circuit to prevent enemy Soldiers or Demomen from destroying your buildings. This setup does, however, leave you with no reliable medium/long range weaponry, so stay close to your Sentry Gun in order to not be taken by surprise.
Alternatively, when using the Gunslinger, you can make use of the reduced cost of the Mini-Sentry to fire a few shots and then still have enough metal to place a Mini-Sentry. Also, you can use the metal output to recharge your supply to continuously throw down Mini-Sentry Guns, keeping a constant force of pressure on the enemy. However, this leaves you mostly defenseless, as a Mini-Sentry is not something to hide behind when you're out of metal. Stay within running range of an upgraded Dispenser to always have a source of ammo.
Frontier Justice
Pistol
Eureka Effect
For a defending Engineer who focuses more on building than retaliating. The Eureka Effect is perfect for jumping back to the nearest spawn quickly for an instant refill, which allows faster nest building and grants the option to quickly fall back and rebuild (or to surprise a Scout/Spy making a bee line for the last control point). Since the Eureka Effect repairs slower, the Frontier Justice counters this hindrance through granting easy crits when your Sentry is inevitably destroyed by an enemy or yourself when falling back/repositioning your nest. Finally, the Pistol/Lugermorph allows you to defend yourself over ranges the Frontier Justice cannot reach and/or to avoid wasting crits.
Shotgun
Wrangler or Short Circuit
Gunslinger
This set is for an Engineer on offense, although not going directly into combat. The Gunslinger's Mini-Sentry Guns are useful for harassing the enemy, and providing an extra gun on the battlefield. The Shotgun is a reliable weapon compared to the Frontier Justice or the Widowmaker, allowing you to provide extra firepower when against the enemy without much fear of losing metal or being stuck in a situation where you need to reload. The Wrangler is useful for setting up your Mini-Sentry farther back and utilizing the Wrangler to harass the enemy from far away, while the Short Circuit is used when you are up close with your team to destroy any incoming projectiles on the cart or a point.
Pomson 6000
Wrangler or Short Circuit
Eureka Effect
The Braniac Pack is well suited to a purely defensive lone wolf. The Pomson 6000's drain effect allows Engineers to slow down oncoming Medics and Medic buddies, or to prevent Dead Ringer Spies from escaping. The Eureka Effect can be used to gather metal from your spawn room while maintaining momentum, and to quickly build during set-up time. However, if your position is overrun, it can also serve as a convenient means of escape. The Short Circuit works well with the Eureka Effect, as its high metal consumption is offset by the Eureka Effect's ability. Alternately, the Wrangler can be equipped to harass incoming enemies from a distance and increase your Sentry Gun's rate of fire and survivability. However, The Pomson fares poorly against enemy Engineer buildings, meaning you will be hard-pressed to counter encroaching Engineers without additional team support.
Pomson 6000 or Frontier Justice or Rescue Ranger
Short Circuit
Jag or Gunslinger
This setup is designed for Engineers who are sharing a nest with other Engineers. The Pomson's ability to drain Cloak and Ubercharge from enemy Spies and Medics may make holding a defensive position easier, whereas the Frontier Justice may be used to store utilize extremely deadly Revenge Crits if your Sentry happens to be destroyed in a rush, making future defensive efforts (or fending off a rush that resulted in the destruction of your Sentry Gun) easier. The Rescue Ranger is used to repair buildings from long range and to harass incoming enemies from range(making up for the lack of a Pistol) and to make an urgent retreat by falling back yourself and then pulling your most important building towards you. The Short Circuit's ability to disintegrate projectiles is very useful for resisting enemy Demomen and Soldiers, and with at least two nearby Dispensers it should not be difficult to maintain a steady supply of Metal for this purpose. The Jag's ability to help buildings build faster is very useful for rebuilding a nest if buildings are destroyed, and can be used to help your fellow Engineers get their defenses up faster as well. The Gunslinger, and the mini-Sentry Guns it provides, are not as useful for long-term defense, but are a decent way to temporarily fill a defensive hole, and cost less metal than a regular Sentry Gun, making defense somewhat more tenable if your use of the Short Circuit has depleted your metal reserves.
Rescue Ranger
Pistol
Jag or Gunslinger
This is a recommended setup for mobile Engineers who are always on the move, but want to be able to have a Level 3 Sentry instead of a Mini-Sentry. The Rescue Ranger allows an Engineer to move his buildings from distances and repair it from a distance, at the cost of metal. The Jag helps to quickly rebuild Buildings that the Engineer just moved to get them ready for action as quickly as possible. The Pistol is used for combat, as both the Rescue Ranger and the Jag are inefficient when in battle. This loadout is especially recommended for Control Point maps where moving buildings across long distances quickly is a necessity.
However, players may choose to use the Gunslinger for a more suitable offensive push. With the Rescue Ranger, this eliminates the need to pick up your sentry normally or even destroy it, but at the cost of 100 Metal (The same as deploying a new Mini-Sentry). This is a good combination for Gunslinger Engineers who don't want to waste time deploying a new one. This combo also maintains the ability to attack/defend easily, this allows the Engineer to constantly attack/defend anywhere while moving from place to place. This is also resolves the issue of the long redeployment time of a Level 3 Sentry Gun, as with the Mini-Sentry, you can constantly grab it with the Rescue Ranger and haul it to a new location to attack/defend.
Rescue Ranger
Wrangler
Wrench or Southern Hospitality or Jag
This weapon combination focuses on providing Engineers with greater utility, opening up a variety of strategical options. The Rescue Ranger, while less usable as a weapon, fires bolts which can repair buildings, allowing you to maintain them from a distance. In the event that movement is necessary, such as with an offensive push or hasty retreat, you can easily bring your buildings with you so long as they are in sight. The Wrangler increases the power and usable range of your Sentry Gun while also greatly shielding it from damage. With it, you can neutralize or rid of threats that are too much for an unwrangled Sentry to handle. In addition, Wrangler Jumping, when used in conjunction with the Rescue Ranger's hauling and ranged repair abilities, can give access to otherwise impossible building locations. Due to the lack of a Shotgun or Pistol, you will often have to resort to your melee weapon in direct combat. The Wrench has no downsides, however the Southern Hospitality provides an additional bleeding effect which can help with fighting enemies at the cost of no random critical hits and extra fire vulnerability. The Jag's increased attack speed can often allow the Engie to have an better chance to deal critical hits, along with quickly rebuild and upgrade fallen buildings. Choose the one which better fits your situation.
For Mann VS Machine, this setup, when paired with the Jag, allows the Engineer to properly support his buildings in the middle of a wave. Since most of the Engineer's credits will be spent on his buildings and (maybe) resistances, he doesn't need to invest points in more than his Wrench's swing speed. As such, this setup excels above all others in MVM, due to the repairing capabilities of the Rescue Ranger, the versatility the Wrangler provides, and the quick building and upgrading speed of the Jag.
While Engineers cannot do much for a Scout aside from his already inherent roles, a Scout can help out an Engineer immensely just by simply doing what he already does well enough without the Engineer.
Soldiers are one of your best friends when at the frontlines due to his immense power. The potential for protection that a Soldier possesses allows an Engineer to be more liberal with the placement of his Sentry nests.
A Pyro is, overall, an Engineer's best friend when maintaining a defensive hold is imperative.
Demomen and Engineers are two of the best defensive classes in the game. Together, they can create a nigh-impenetrable defense.
Heavy benefits significantly from the buildings that Engineers build. Additionally, the Heavy's presence in and of itself can help an Engineer by diverting attention from a Sentry Gun's placement until it's too late for the enemy.
While one Engineer on his own is quite powerful, a pair or group of Engies can make for a level of defense that is unrivaled by even the most resilient classes.
Medics rarely keep company around, or heal their team's Engineers due to the necessity of keeping combat classes alive. Medics take a lot of fire from enemies and are considered a top priority target by Scouts, Snipers and Spies. All of the Engineer's buildings can directly help or protect a Medic who is under fire and allow them to flee with their ÜberCharge percentage unscathed.
Engineers and Snipers do not have much synergy, but still can help cover each others' weaknesses.
Due to the differing roles of the classes, Spies and Engineers generally don't work together well. However, one can indirectly help the other, even without knowing it.
