Alessio Piergiacomi
Pragmatic
Systems thinker
Strong opinions, loosely held
Customer first
Community builder
Hi, I'm Alessio, and I built this website to talk about my work history in a different way, free from constraints on what you should put on a CV. You'll find quotes from my performance reviews and peer feedback, plus some opinions on engineering culture, values and trends.
Since I joined Meta in 2020 I've been working as Privacy/Infrastructure Engineer on the platform responsible for executing deletions across different data systems for products built by thousands of teams working on products such as Facebook, Instagram, Threads, Whatsapp Business. Reliability and efficiency are critical concerns, but so are correctness and completeness: after mistakes of the past, there is strict external oversight in place.
In 2015 I attended a random meetup and got intrigued about a yet-to-launch app called Mondo. I later became an enthusiastic beta user, and in 2018 I realized I liked the product so much that I wanted to work on it, and I managed to get hired as Product/Backend Engineer at the by-then-renamed Monzo. I learnt a lot about startups and product development there, and one of the highlights was the very active community forum, a place where you could find feedback of all sorts (and then learn to take it with a pinch of salt 😅).
The company that culturally shaped me most is Amazon, despite my tenure of just under two years. Maybe I was younger and more malleable, but many of its Leadership Principles resonated deeply with me, and still do almost a decade later. We used to joke it was indoctrination, but in hindsight it was a sort of 10,000-foot mentorship from Jeff. My favourite ones were Customer Obsession, which implies caring about the product and the users (and that speaks to my inner Steve Jobs), and Ownership that also implies caring and giving a damn.
I value Autonomy and I am happiest as a senior individual contributor: close enough to the code and data to discover what is really happening, and able to influence direction, reliability and engineering standards.
I have a nuanced love-hate relationship with the term efficiency. I love efficient code, and working in a pragmatic way, but I have a dislike for the Cult of efficiency that has spread around quite a bit in recent years: I value buffers, in infrastructure and engineering capacity, as I've assisted to being extremely lean backfiring more than once.
I love non-fiction and technical books, and discussing them in book clubs. I participated (organizing in some cases) to four different technical book club series. It's possible most technical books are not relevant anymore in 2026, but I believe discussing best practices will still be, as long as there will be software engineers.
On the subject of the AI Cambrian Explosion, these days coding agents write >90% of my code, but I wouldn't define myself an AI-Maxxer. While I adopt small self-contained loops, I think a dark factory on a big and complex monorepo is still a bad idea as of mid-2026. However, I can see this becoming a thing in future, just not while yet: you don't want to be hemorrhaging millions of dollars while your Ops agent hit a wall and can't figure out how to fix an issue, and no human understands any of the code.
Under the relevant company policies, I’m able to share selected excerpts from my performance reviews.
What follows is a small selection, lightly edited only for context and anonymity where needed.
“I saw his ability to foresee the long-term consequences of his choices. Alessio anticipates the complexity of decisions and breaks them down into pieces that are easy for the team to consume. He is a strong problem solver.”
Peer feedback
“He is always on the lookout for potential problems and owns the mitigation rather than just throwing the responsibility to the oncall, who is already busy. This helps the team quite a lot under the difficult circumstances where we were understaffed and overloaded with operational issues.”
Peer feedback
“Alessio came in, analyzed the situation and set a new direction: remove the feature as the cost of the migration is high and the feature has no usage. This allowed us to close the privacy work with [...] 1 diff. This saved us 2-3 months.”
Peer feedback
“Alessio gave pretty much perfect actionable feedback on how to make a part of [company program] better. Because of how clear and actionable this was, through examples we skipped the backlog and shipped it; #movefast and thanks for the help!”
Principal engineer
“What stands out most is Alessio's ability to scale his impact by enabling others. Last half, he was the sole facilitator for early sessions. This half, he grew that to 6 active facilitators - a clear example of his skill in empowering others through simplicity and leading by example.”
Peer feedback
“Alessio has been a fantastic XFN partner, bringing a deep understanding of deletion systems and conducting detailed investigations. [...] He opened a SEV in response and reached out to POCs across [database team] and IG/FB product teams to identify ways to remediate and measure product impact. I greatly appreciate Alessio's incredible attention to detail and transparency in communication.”
XFN partner feedback
“Alessio is a well-deserved engineering excellence SME [...], and this half he continued to demonstrate why he holds that reputation [...] He organized a Better Engineering week, inspiring the team to work on meaningful improvements.”
Peer feedback
“Alessio entered the problem space without any hints of structure or direction. Alessio gave it structure by measuring concrete aspects (tasks, alerts, failures, etc), which then he used to define the project's direction. This led to many improvements being successfully landed... The amount of Better Engineering impact delivered was off the charts.”
feedback from a v-team peer
“Alessio has a great sense of ownership. He investigates difficult issues and offers solutions to resolve not just mitigate [...] he is a staunch defender of our Operational Excellence and ensures that long term quality is not dropped even if we have to make compromises in the short term.”
Peer feedback
“Alessio led the charge in the culture change in the SEV reviews. In addition to owning 8, he participated in every single review. We're doing SEV reviews per company standard only because of relentless efforts.”
Peer feedback
“He is my favourite reviewer because he does not shy away from asking questions and pushing back... He provides thorough reviews and rarely stamps. This allowed me to find bugs early in [project] and fix them before landing.”
Staff+ Peer feedback
“Alessio has been the primary torch bearer of the multi-tenancy project... he correctly deduced that because [...] we needed a scalable infrastructure of rate limit enforcing and hence moved to [...]. This was the breakthrough the project needed [...] Alessio is one of the most productive engineers I have ever worked with.”
Staff+ production engineer feedback
“Alessio was one of the pillars of our team in 2022. He consistently showed ownership across the board [...] He championed reliability this year [...], he led by example, as one can see from the number of SEVs he was involved in. In 2022 Alessio became a Deletion Framework expert that understands the full system, how all pieces interlock and how DF sits in the larger Meta landscape. This allowed him to become a force multiplier for the team.”
Peer feedback
“Alessio is currently considered the “Problem Umbrella” for the rest of the team. As the main POC for external stakeholders Privacy-Aware-Infrastructure related, Alessio shields the team from this bureacratic work and ensures we can keep relying on the abstractions we're used to.
Peer feedback
“Near the start of the half I dumped a 💩 project on Alessio's plate.. The tooling wasn't really ready, so Alessio put in a large amount of effort to work with [...] to onboard with [some experimental but privacy-mandatory infra]. The outcome is that Deletion is now declared safe, and we will build on this work in the [internal program] track to reuse this pattern for other core infra system.”
Senior Staff Engineer feedback
“Alessio is one of the strongest members of the Deletion Systems' team [...] his willingness to work with the new joinees is a great strength and helps the whole team in the long run. [...] He and I collaborated on the on-call experience [...] and he was the most active editor of the on-call runbook.”
Peer feedback
“While mitigating the SEV Alessio demonstrated strong leadership and XFN skills [...] Setting up regular sync between Deletion Framework, [two other infra teams]. This brought relevant teams together [...] Once we came up with the root cause theory, Alessio owned the mitigation part by introducing jittered delay on failure and very effectively rolled out the change.”
TL from different team
“He doesn't do this to get recognition—but it's noticeable when Alessio is around. Everything just runs so much better.”
Peer feedback
“I don't know anyone as committed to our customers as Alessio. He will consider every potential impact when we're building new products.”
Peer feedback
“Besides setting the bar for how product engineers should work, he is also really quick at improving from feedback from the team.”
Product manager
“On multiple occasions he’s flagged issues nobody else had considered. In every situation it comes from going the extra mile to think—and solve—for scenarios nobody else has thought about.”
Peer feedback
“I’ve never seen Alessio say no to helping someone else. He constantly supports engineers across the organisation.”
Peer feedback
“Alessio is my go-to person when it comes to debugging. When it comes to investigating issues, Alessio is my role model.”
Peer feedback
“Alessio is wonderfully approachable. When he doesn't know the answer, he'll know where to find it and help you find it for yourself.”
Peer feedback
“Alessio is really good at jumping onto a problem and finding a solution, even if all the information he’d ideally have upfront isn’t there.”
Peer feedback
“When we’ve worked together, he’s always taken the time to sit down with me and talk through all angles of the problem.”
Peer feedback
I wasn’t yet in the habit of keeping feedback from this period.