SAN FRANCISCO — Elon Musk’s Twitter is a house of cards.

On two occasions recently, almost exactly a month apart, minor changes to Twitter’s code appeared to break the website.

The latest outage came Monday as thousands of users found they could not access links, photos, or other key aspects of the site.

“A small API change had massive ramifications,” Twitter CEO Elon Musk wrote in a tweet on Monday, referring to the tool used by third-party developers who run programs that draw on Twitter data and post to its site. “The code stack is extremely brittle for no good reason. Will ultimately need a complete rewrite.”

It was the second time Monday he’d turned to that explanation, both times calling the site “brittle.”

Since taking over Twitter, CEO Elon Musk has laid off more than two-thirds of the company’s staff, embarking on aggressive cost-cutting and shedding workers in part by compelling them to commit to an “extremely hardcore” workplace or leave the company. The massive layoffs led to widespread concerns about Twitter’s ability to retain core functions, as critical engineering teams were reduced to one or zero staffers.

In the months since the takeover – and subsequent layoffs – Twitter has faced multiple outages, hampering key features: loading tweets and notifications, sending tweets and direct messages, and accessing links and photographs. Each was said – by staffers current and former, or Musk himself – to come as the company made changes to its code.

“Every mistake in code and operations is now deadly,” a former engineer who spoke on the condition of anonymity for fear of retribution told The Washington Post in November, explaining that those leftovers were “going to be overwhelmed, overworked and, because of that, more likely to make mistakes.”

Before Musk’s takeover, the company had a risk evaluation team that vetted product changes for anticipated problems. Twitter’s risk evaluation process was geared at flagging potential problems before they arose. But the team was laid off after Musk’s takeover, The Post reported, leading to product rollouts that were riddled with bugs.

Musk and Twitter did not immediately respond to requests for comment.

Since taking over Twitter, Musk has followed through with a plan to cut 75 percent of the company’s staff, aggressively cut costs, and pursued new revenue streams, such as charging $8 a month for the company’s signature blue verification icons. But his tenure has also been marked by embarrassing mishaps, such as the botched rollout of the check mark feature, which resulted in a swarm of impersonators and prompted Twitter to pause the subscription service on multiple occasions temporarily.

Musk pursued Twitter pledging to restore “free speech” to the platform, firing the company’s previous slate of managers whom he had blamed for a content moderation approach rooted in protecting against the harms of hate speech and misinformation. Musk also pledged transparency on the old regime’s decisions – such as the effort to limit the spread of a New York Post story on the contents of Hunter Biden’s laptop – but has cracked down on leaks of company information under his leadership.

Even before Musk’s takeover, Twitter employees had warned of the site’s vulnerabilities in the event of an outage. Twitter whistleblower Peiter Zatko cautioned about a potential event of overlapping outages at Twitter’s off-site data centers, for example, in a complaint obtained by congressional committees.

That type of outage, he said, could leave critical data unrecoverable – and cause Twitter to go down for months. Despite the concerns about Twitter’s vulnerable infrastructure, Musk ordered Twitter’s largest data center, in Sacramento, to be shut down in December, The Post reported at the time.

On Monday, Twitter users were greeted with glitches almost as soon as they opened the site.

When users clicked a link on Twitter, they were met with the message: “Your current API plan does not include access to this endpoint,” it read, and directed them to a page intended for developers.

On the website Down Detector, which tracks online outages, complaints surged: “User reports indicate problems at Twitter,” it said.

“We made an internal change that had some unintended consequences,” Twitter’s support account said in a tweet.

By late morning, some of the functions appeared to be restored.

“Things should now be working as normal,” Twitter’s support account said in a tweet. “Thanks for sticking with us!”

The pattern on Monday mirrored an outage from early February, which arose as Twitter was making similar changes to its API, the data feed intended for developers.

Twitter faced a widespread outage on Feb. 8, that left users unable to send tweets and direct messages, follow other accounts, and load content in their timelines.

“Starting February 9, we will no longer support free access to the Twitter API, both v2 and v1.1. A paid basic tier will be available instead,” Twitter wrote that month.

Musk said Twitter was trying to crack down because Twitter’s freely accessible data was being “abused” by bots peddling scams, but later said the company would make a free version available, as criticism poured in over his aggressive efforts to monetize aspects of the site that were free before.

That set of problems followed a widespread global outage Twitter faced in December.

In group chats among current and former engineers at the time, some speculated that the December outage had come after a software update had gone wrong.

Monday wasn’t the first time Musk suggested Twitter’s code needed to be entirely rewritten. He has maintained that stance for months, since taking over the site last year. On a December Twitter Spaces, the site’s live audio feature, he said the company’s code base needed to be overhauled.

Pressed by a participant to explain what that meant, Musk grew irritated.

“Amazing, wow,” he said, after hesitations and pauses. “You’re a jackass. … What a moron.”