Black Mirror
When you open Black Mirror or another anthology series like Love, Death & Robots, something strange happens — the seasons aren’t listed in order of release, but from newest to oldest. For most shows with a linear story arc, this makes absolutely no sense, but for anthology series, it doesn’t matter where you start. What you may not realize is that this seemingly straightforward functionality didn’t come easily to Netflix engineers.
As you may know, Netflix picked up Black Mirror from Channel 4 after the third season and has just recently released season 7. When season 4 launched, Netflix didn’t want new viewers’ first experience of the series to be the first season; they wanted users to see the brand new, swanky season. There’s also the issue with the first episode being about f**ing a pig too…
That switch — showing Season 4, Episode 1 as the default instead of Season 1, Episode 1 — might seem like a minor UX decision. But behind the scenes? It kicked off a four-month, multi-service technical meltdown that still haunts developers to this day. That’s according to software engineer Michael Paulson, who is both a famous YouTuber going by the name ThePrimeagen and a software engineer at Netflix.
Internally, the request was simple: “Let’s show Season 4, Episode 1 as the first thing viewers see.” But this created a paradox: Netflix needed to reverse the season order, but not reverse the episode order within each season.
As Paulson explained, Netflix is powered by hundreds of microservices — small, specialized systems that each handle specific tasks that you take for granted every time you boot up Netflix. That architecture is robust and powerful, making for a speedy system… until you need to make a small global change.
But under the hood, Netflix’s platform wasn’t designed for a change like reversing the order of seasons. Every part of their systems expected a series to appear in chronological order — Season 1 first, then Season 2, and so on. Reversing that order — just for one show — ended up being far more complicated than anyone expected.
Paulson explains some of the systems at play here, suggesting that making changes like this led to changes in other systems, which wouldn’t know how to handle things or, at worst, would crash entirely.
- One system, called GPS (Gallery Presentation Service), was in charge of listing shows and episodes. By default, it always showed Season 1 first — because that’s how most shows work. This is also sometimes referred to as LOLOMO, which means a list of lists of movies.
- Another system, called MAP (Metadata Aggregation Platform or Media Access Platform, depending on the version), tried to personalize what you saw, such as showing a popular or recommended episode first. But it had to work against GPS to put Season 4, Episode 1 at the top instead.
- Then there’s VMS (Video Metadata Service), which then taps into other services such as one called Dexter, which stores basic information like episode titles and air dates. It didn’t know anything about special ordering — it just passed along the raw data as it was initially published.
To fix all this, Netflix had to bring in a more advanced layer or tool called CMS (Content Metadata Service). Its job was to step in and say, “Hey, for this show, we’re doing things differently.” It had to reorder the seasons dynamically, using special rules that only applied to anthology shows like Black Mirror. But it got even more complicated from there with various calls and other new systems having to be integrated to talk to old systems and so forth.
One of the engineers who worked on the fix said it took around four months to get everything working correctly. The team had to build new tools, rewrite existing systems, and even deal with naming disagreements between teams. At one point, they had to rename a small technical setting just because another team didn’t like how it sounded.
“All this,” Paulson said, “just so the pig episode wasn’t the first thing you saw.”
Netflix’s microservices conundrum!
The full video about MicroServes and how Netflix had to go through lots of iterations to fix Black Mirror can be found in the video below:
Rating: TV-MA
