Timeline

The timeline of PAYDAY: The Heist has no official order of which the heists take place in-universe, or canonically.

PAYDAY 2 used to also have no official timeline, and with the much larger array of heists, was more frequently debated, with only few things certain. That was the case until the release of the FBI Files, which contains an official timeline in the "Heist Database". However, some people question whether it is the actual timeline or just a possible order.

PAYDAY: The Heist (2011-2012)

There is little continuity within the heists in the first game, with only the order of the heists in the heist selection menu indicating some sort of timeline.

All that is known for certain is that First World Bank is the first heist in the game, as based on its position on the list in the heist selection screen, the description of the heist, newspapers in Counterfeit, and the description of the heist's PAYDAY 2 remake plus comments by Bain, and Counterfeit occurs after at least Slaughterhouse, if not every heist in the game, as when putting the drill on the Frank Yaeger safe, Bain will comment on how unlike the "other ones", this drill won't jam. It is also presumed Undercover is the last heist to take place in PAYDAY: The Heist due to it being at the bottom of the heist selection screen list.

It has been confirmed by both Overkill Software and Valve Corporation that No Mercy is not canon in neither the PAYDAY universe nor the Left 4 Dead universe.

Hoxton Arrest (2012)

At an unknown time between the setting of the first and second game, the original Hoxton was left behind after a job gone sour. However, all of this was after the first PAYDAY game as his lawyer in "Intro" song in the Merry Payday Christmas Soundtrack says "Look, they got you. You understand? They got you good. You were caught on tape at the Garnet Group break-in, your fingerprints were all over the panic room, and your apartment is filled with blueprints from banks in D.C." This suggests that they had already moved to D.C. He was arrested by the Federal Bureau of Intervention and incarcerated at the same high security prison, Hazelton, and cell as their previous driver, Matt, whom he regularly beats up, which he sees as "karma" for double-crossing them.

PAYDAY 2 (2013-Present)

It has been confirmed by Overkill that PAYDAY 2 takes place after PAYDAY: The Heist.

In the basic heists, Bain mentions it has been two years since Dallas has last participated in a heist, which would align with the release dates of PAYDAY: The Heist and PAYDAY 2.

There were also various boxes in the pre-Update #110 safe house named after various heists from the first game. It is speculated that these boxes contain loot or equipment from those heists.

Pre-FBI Files Release

Until the FBI Files were released, confirming PAYDAY 2's timeline, the order in which the heists took place was almost entirely up in the air. All that was known at the time was that Hector's heists took place in a definite order, along with The Dentist's and The Butcher's heists, though the order of The Dentist's heists are less defined. Additionally, some voice lines indicate a sort of order regarding Vlad's heists.

Hector Timeline

It was known for certain that Watchdogs takes place before Firestarter and Firestarter before Rats, both based on Hector's comments at the end of the former, and the elimination of the Mendoza cartel's D.C. operation in Rats would make Firestarter occuring after Rats impossible.

The Dentist Timeline

Even though not one of The Dentist's heists, he and his heists put The Elephant's Election Day heist along The Dentist's timeline.

In The Dentist's introductory video, he mentions the First World Bank and Election Day heists while talking to Dallas, along with teasing some of his heists, supporting that Election Day occurs before any of The Dentist's heists.

Hotline Miami is The Dentist's second heist, following The Big Bank. In the heist, the Payday Gang kills The Commissar so The Dentist can convince the District Attorney, whom has relations to the Commissar, to lower security around Hoxton. Since the Election Day heist is committed so The Elephant can have Hoxton be transferred to a lighter-security prison, Hotline Miami would have to occur after Election Day, as if it were the other way around, the act of lowering the prison's security would be moot, since Hoxton would be transferred to a different prison anyway.

The Dentist's next two contracts are Hoxton Breakout and The Diamond, though it was unclear in which order. In the Hoxton Revenge heist, The Dentist's fifth heist, evidence boards show footage of Clover breaking into the FBI office with the rest of the crew in Hoxton Breakout, even though she was released alongside The Diamond, released after Hoxton Breakout.

The Dentist's last heist is Golden Grin Casino, taking place after each of his previous heists. Said heist takes place before the Reservoir Dogs Heist, Breakin' Feds, and Henry's Rock with Bain's demise and the box bearing very similar markings like the other ones taken by the crew. 

The Butcher Timeline

The Butcher's two heists occur in a "What if?" scenario.

The Butcher's Forest contract takes place if the crew doesn't do the Dockyard contract, and the bomb is loaded onto the train that the gang assaults in the Forest heist. However, neither heist retcons the other, both heists canonically taking place in the PAYDAY universe.

Vlad Timeline

In Meltdown, which takes place after Shadow Raid as indicated by the open, empty samurai armor vault, when one of the warhead cases is opened, Bain may reference the Mallcrasher and Ukrainian Job heists ("Vlad, smashing malls is one thing, stealing tiaras is one thing, but nukes?!"), indicating that those two heists take place before Meltdown, and likely Shadow Raid.

In Aftershock, when one of the safe trucks is opened, Bain will reference the Ukrainian Job and Meltdown heists, further reinforcing the heist order in the files.

Goat Simulator takes place sometime after Hector's death (and therefore, Hoxton's Revenge), in which Vlad mentions the death of the former drug lord created a void in the powder trade.

Post-FBI Files Timeline

The release of the FBI Files not only confirmed that the heists added to the game post-release take place in the order they were released in, clearing up the mystery around Hoxton Breakout and The Diamond, it also confirmed the order the heists in the game since its release are in. It is shown in the Heist Database that Four Stores is not only Vlad's first heist, it is also the first heist in PAYDAY 2. It also confirms Jewelry Store to be Bain's first contract and Big Oil to be the Elephant's first. It also shows that Beneath the Mountain is Vernon Locke's first contract, though this might just be due to alphabetization.

Jimmy Timeline

Murky Station takes place before Boiling Point, as in Murky Station the crew and Jimmy steal the EMP bomb they need to access the hidden lab in Russia in Boiling Point. Also, Murky Station occurs after Locke's Beneath the Mountain  and/or Birth of Sky heists (but alledgely, prior to Alaskan Deal), as Bain mentions stealing the EMP bomb would earn favors for him. 

Vernon Locke Timeline 

At some point after the PAYDAY crew conducted heists on Murkywater such as Shadow Raid and Meltdown, Vernon Locke manages to infiltrate Crime.net with the original intention of destroying it as tasked by the shady organization in an act of vengeance. However, being the mercenary he is, Locke instead proposes to work together or otherwise he will "press a red button" to shut down Crime.net for good. Bain, having no other choice, agrees with Locke's offer. The mercenary then pushes the PAYDAY crew to steal valuable items in a Murkywater stronghold and infiltrate a cargo plane owned by Murkywater to retrieve pallets of cash and eject from said plane. 

Eventually, Locke receives a tip off that leads the crew to pursue the treacherous Matt on Heat Street, claiming "an organization is set out to destroy the gang" with Matt being a possible member. He assists the gang in sending Bile to extract them once after Matt is apprehended. 

All seems well until Locke arranges a weapons deal with The Butcher in Alaskan Deal. Soon after the crew arrives, Locke seemingly betrays them and leaves the area for the police force to capture or kill the gang. Bain swears his revenge and promises to get even with him. The PAYDAY crew succeeds in escaping, and proceeds to subsequently cut off Locke's finances in the Diamond Heist. 

In a surprise twist, Locke returns but this time, assists the crew when Bain himself is apparently captured or killed by unidentified enemies in the Reservoir Dogs Heist. Bain's last words mention to trust Locke in spite of his earlier betrayal and says he was "getting close to something big". The mercenary promises to take care of the crew and expresses his condolences for Bain's demise. With his absence, Locke has taken over Bain's role and leads the PAYDAY gang in Brooklyn Bank where they unearth a clue. 

As revealed in Brooklyn Bank, Locke claims that Murkywater is responsible for the latest events and has caught ear of his acts against the mercenary force and therefore, has severed their communitcation ties with him. 

After The Elephant becomes detained, Locke orders the crew to retrieve a box that was previously under the crooked politician's possession in the Breakin' Feds heist. Solomon Garrett is present but the crew avoids alerting and killing at all costs as ordered by Locke. The crew steals the box and with the last of his Murkywater personal favors being used up, Locke sends them to Henry's Rock, a Murkywater secret underground facility that holds two additional boxes of certain interest. However, the PAYDAY gang is exposed and forces the heist to go loud, with waves of both Murkywater PMCs and law enforcement swarming the facility. Undeterred, the gang succeeds and escapes with the intended possessions. 

The Classic Heists

Starting with Update #84, missions from PAYDAY: The Heist were reintroduced into PAYDAY 2 as Classic heists. The canonicity of these heists are not clear, as some elements of the remade heists contradict with their original depiction.

• First World Bank is stated in-game to be a revisiting of the bank after it reopened following its previous robbery, and the FBI Files allude to this stating it has "all the hallmarks of a classic job", but its location appears to have been moved from New York to Washington D.C. This fact is made even weirder by the later Heat Street remake still taking place in New York and containing advertisements featuring the First World Bank.
• Slaughterhouse does not make any allusions to being a redo of the earlier heist and Bain's briefing and the heist's file in the Heist Database imply that this specific heist has not been done in the past.
• Counterfeit's Heist Database file states that the counterfeiting operation had been ongoing for years, meaning the original heist never took place, assuming the file is canon.
• Undercover has the entirely same premise as the original, but the remake's Taxman goes under the name Adrian rather than Eugene. The same heist occurring but with a different yet related IRS employee, involving a similar 25 million dollar hack, is rather strange, however not entirely implausible.
• Panic Room, on its announcement page on the Hoxton's Housewarming Party, is stated to be a reenactment of the original by the request of Sydney, but in-game it is stated that should the heist be successful, it will go down in history, implying that a similar heist did not previously occur in-universe.
• Heat Street canonically occurs twice in-universe, with Bain noting that the experience is similar to a past event.
• Green Bridge seemingly also occurs twice, yet Solomon Garrett's notes imply that an incident like it has not been seen before.
• Diamond Heist, possibly occurs twice, based on Ralph Garnet's voice mail to his father in the heist trailer.

Trivia

• GO Bank, White Xmas, Stealing Xmas, and Santa's Workshop are the only heists known to take place during winter. The trailer for The Diamond heist shows a Christmas tree in one of the rooms, showing that it was previously meant to also take place in winter.