The Pragmatic Engineer – “What is a Principal Engineer at Amazon?” with Steve Huynh

Host: Gergely Orosz
Guest: Steve Huynh (17-year Amazon veteran, former Principal Engineer)
Date: July 9, 2025

Episode Overview

This episode provides a deep dive into the principal engineer role at Amazon, one of the toughest and most unique engineering positions in Big Tech. Steve Huynh, who rose from support engineer to principal over 17 years at Amazon, shares inside stories about Amazon’s scale, culture, technical challenges, and what it means to become (and thrive as) a principal engineer. The conversation is especially relevant for software engineers and leaders aiming to understand technical career ladders, large-scale engineering, and the reality behind Amazon’s internal reputation.

Key Discussion Points & Insights

Steve Huynh’s Amazon Journey

• Career arc: Started as a support engineer, transitioned into software development, worked on projects including Search Inside the Book, Kindle’s launch, Prime Video precursor, Amazon Local, Restaurants, Tickets, and live sports streaming on Prime Video. (01:28)
• Tenure: 17.5 years at Amazon, left about a year before the recording. (01:16)

Internal Mobility & Company Structure

• Movement between teams:
  • Early on, movement was restricted; VP/Director could block transfers, causing high attrition on “bad” teams.
  • Policy changed to allow “freedom of movement”; as long as not on a performance plan, engineers could transfer more freely. (04:40–07:30)
• Internal hiring preference:
  • Internal hires are lower risk, familiar with company culture/process. (07:57)
  • “Most of our hires have been internal... It’s a low risk hire.” (07:58)

Scale & Engineering Challenges at Amazon

• Massive scale examples:
  • Prime Video’s gateway page and retail homepages receive “tens or hundreds of thousands of requests per second,” each request fans out into “hundreds” more internal service calls. (10:01–11:36)
  • Minor changes can inadvertently DDoS internal services.
    • “If you change a caching configuration... you’ve just browned out a critical service.” (11:36)
• Brownouts vs. blackouts:
  • Brownout: Service is reachable but only partially functioning; timeouts, partial/bad results, random 500 errors. (11:57)
  • Recovery requires managing load after a dependency returns to avoid repeated outages. (14:42)

“You own that piece of software... you cannot write the software, hand it over to the testing team and then throw it over to the SRE team after you’re done.”
— Steve Huynh (16:06)

Performance, Latency, and Amazon’s Monolith Origins (17:36–26:35)

• Latency directly impacts revenue:
  • Amazon invested in logs/telemetry; discovered faster page loads directly correlated with increased gross revenue.
  • “If you’re faster, you just make more money. It’s a pretty clear correlation. I think you would even go as far as to say it’s causation.” (17:36)
  • Led to a culture of “why not 1ms?” performance targets.
• Monolith evolution:
  • Amazon started as a single huge C-based monolith (“vertical scaling”).
  • Outgrew 32-bit binary/4GB limit, moved to service-oriented/microservices architecture.
• Microservices tradeoffs:
  • Microservices enable team autonomy and scalability but add complexity and latency.
  • Ongoing challenge: Optimizing blocking calls, reducing dependencies, and gracefully degrading under load.

“In a world where you have to... the best performance that you can actually get is always going to be bounded by the number of web requests that you end up making.”
— Steve Huynh (21:43)

• Advice for startups:
  • Start as a monolith, break up only when it becomes unwieldy with developer headcount. (26:09)

The Principal Engineer Role at Amazon

Promotion Structure & Career Path

• Career ladder:
  • Junior → Mid → Senior (L6) → Principal (L7), with no “staff” level to bridge the gap.
• Hardest promotion:
  • “You have to do like 2½ [levels]” to jump from Senior to Principal.
  • External brain drain occurs because many strong seniors leave for companies with more sane progression (Meta, etc.). (27:16–30:17)

“Principal is L7... at Amazon, that jump is so big because there’s no staff level in between.”
— Steve Huynh (27:40)

The Principal Engineering Community

• Community features:
  • Tight-knit, highly curated, based on “overly high standard.”
  • In-person offsites (pre-pandemic), active principal Slack, presentations (“Principles of Amazon” series, internal and recorded for 20 years).
  • “Everyone that was able to achieve that... there’s something exceptional about them.” (30:52–33:59)
• Notable quote:
  • “You could just scoop out five people and then put them into a room and the conversation is just... amazing, right?” (32:09)

Knowledge Sharing & Postmortems (Correction of Errors – COEs)

• Blameless, open culture internally, hundreds of detailed internal COEs.
• Learning from past outages is “part of the secret sauce.”
• “You have this stream of disasters... and you just... learn so much from that.” (37:23)

Common Paradoxes & Realities of the Role

Bhavik Kothari’s (current principal) list of challenges:

1. Paradox of Belonging
   • Part of all teams, yet of none; act as floating advisor, not embedded. (39:08–41:56)
2. Paradox of Freedom & Responsibility
   • Given total autonomy (“assigned a direction, not a problem”), but accountable for enormous impact.
   • “My manager was a VP... and he didn’t assign me work. He just set a direction.” (42:11–44:25)
   • Principal can solve needs via code, architecture, process, or buying software—total menu of tools.
3. Bandwidth & Presence
   • Overbooked with meetings; “My day looked like most people’s week... It looked like... a Tetris factory blew up.” (46:59)
   • Must ruthlessly prioritize, cut noise, learn to say no; otherwise, burnout inevitable.
   • “If I just went to all the meetings... I’d literally have no time to do the work.” (47:22)
4. Breadth & Impostor Syndrome
   • Expected to be expert on everything—tech, AI/LLMs, policies, etc.—but risk assuming more expertise than reality warrants.
   • “There’s this trap... you speak as an authority, even though you haven’t had the requisite time to ramp up on something.” (54:51)
5. (Bonus) Performance Reviews
   • Principals pulled into calibration/performance reviews for large orgs, similar to managers but without direct reports. (50:46)

Amazon’s Engineering & Corporate Culture

Leadership Principles & “Secret Sauce”

• Principled thinking > the content of the principles:
  • “The meta-level thing is... these guys have principles that they won’t budge on.”
  • “What does it actually mean to be principled and not bend when it could be really easy to do so? That’s the secret sauce.” (55:14–58:38)
• Core principles felt most: Customer Obsession, Bias for Action, Ownership.
  • “We’ll just burn money to delight a customer.” (56:37)
  • “Just get stuff done; stop asking for permission.” (56:40)
  • “You own your software; you do the operations, you own the bug count.” (56:42)
• Writing culture:
  • Six-page memos/tradition (“six-pagers,” PRFAQs) frame business and tech proposals.
  • Study-hall meetings to read docs together, then discussion.
  • “I spent on the order of one to four hours every day reading, while I was a principal engineer.” (59:06)
  • Culture enables rapid onboarding and deep institutional knowledge.

Patents & Technical Achievements

• Patent system:
  • Principals often hand their key designs/writings to lawyers, leading to many software patents.
  • Story of building one of the world’s fastest ticket sale platforms at Amazon Tickets by leveraging CPU cache and bit manipulation—real-world systems/applications of computer science. (61:25–66:37)

Notable Quotes & Memorable Moments

• On Principal Engineer Impact:

  “You’re assigned not a problem, not even a problem space. You’re assigned a direction.”
  — Steve Huynh (44:25)

• On Unfairness of Promotion:

  “Some of the best engineers that I’d ever worked with were having such problems getting to principal engineer that they ended up moving... to other places where the progression was just sane.”
  —Steve Huynh (28:46)

• On Leadership Principles:

  “What does it actually mean to be principled and to not bend when it could be really easy to do so. So that’s an amazing secret sauce of Amazon’s... It’s principled thinking.”
  —Steve Huynh (58:38)

• On Learning and Meta-Skills:

  “How can I quickly learn skills that makes you... recession proof?... It’s essentially meta learning.”
  —Steve Huynh (68:02)

Patent War Story

• Ticket sales optimization:
  • “What if you loaded all of that inventory into L2 cache on a CPU?... do bit manipulation to really quickly get contiguous seats.”
    (65:44–66:37)

Timestamps for Key Segments

| Timestamp | Topic | |-----------|-------| | 00:00 | Episode opening & approach to performance at Amazon | | 01:16 | Steve’s Amazon tenure and high-level job history | | 04:40 | Internal transfers, policy change, freedom of movement | | 10:00 | The scale of microservices and personalization | | 11:36 | Brownouts and system-wide consequences | | 17:36 | Latency’s effect on revenue and roots of Amazon’s architecture | | 26:09 | Monolith vs Microservices tradeoffs, advice for startups | | 27:16 | The uniquely tough jump to principal engineer at Amazon | | 30:52 | The principal engineering community & professional network | | 37:23 | Internal “correction of errors” (COE) and learning culture | | 39:08 | Principal engineer paradoxes (belonging, accountability) | | 44:25 | Autonomy and expectation of resounding impact | | 46:59 | Bandwidth challenge and overbooked schedules | | 54:51 | Breadth, authority, and humility (LLMs & tech trends) | | 55:14 | Amazon’s leadership principles and “principled thinking” | | 59:06 | The writing and reading culture (six-pager memos) | | 61:25 | Patents, defensive IP, and the Amazon Tickets system story | | 68:02 | Steve’s top career advice: meta-learning | | 69:33 | Favorite programming languages (Perl, Rust, Java) | | 71:19 | Recommended reading: Cal Newport’s “So Good They Can’t Ignore You”; DDIA, etc. |

Recommendations & Resources

• Books:
  • So Good They Can’t Ignore You by Cal Newport (career capital & skill-building)
  • Designing Data-Intensive Applications by Martin Kleppmann (DDIA)
  • AI Engineering by Chipwin (cutting-edge technical reference)
• Steve Huynh online:
  • YouTube channel and newsletter (links in show notes)
• For deeper company engineering insights:
  • Subscribe to The Pragmatic Engineer newsletter.

Takeaways

• Amazon’s principal engineer role is hard to get, high in status and impact, but comes with paradoxes—high autonomy, expectation of large impact, and persistent bandwidth/focus stress.
• Internal culture thrives on principled decision-making, writing and sharing knowledge, and blameless learning from failure (COEs).
• Breadth of expertise and comfort with ambiguity are essential to thrive; mentorship, networking, and resilient systems thinking are paramount.
• Amazon’s technical architecture and org structure have been shaped by scale-driven needs, and despite debates, starting as a monolith still makes sense for most startups.
• Meta-learning—building the capacity to swiftly acquire new skills—trumps learning any one language or toolset, and is the best defense against career stagnation.

This summary reflects the conversational, transparent, and sometimes self-deprecating tone of both the host and Steve Huynh, aiming to inform and inspire ambitious engineers and tech leaders about the true nature of technical leadership at scale.