What FDE coding rounds test, by the evidence

One candidate reported on Reddit, in April 2026, spending about 40 minutes of an hour-long CoderPad round inside roughly 100 lines of someone else’s Python, for a “more customer facing” forward deployed role, company unnamed. ^[1]Source 1Had a debugging interview, fixed the bug but took a while. Am I cooked? (post by u/Boring_Distance_7320)PublisherReddit r/recruitinghellSource typecandidate report on Reddit The bug was > 0 where >= 0 belonged. That is a coding round too.

FDE coding rounds don’t share one format. By the end you can sort a target’s evidence by kind and plan a week of drills: the coding half of the double bar.

The split in the evidence

Name the kind first. Blank file or someone else’s code? A set problem or one that grows? A dataset makes it a data round. Each rewards one habit and fails on one mistake, in our reading:

A fictional EV charging network could pose all five:

• Algorithm. Find the station with the most chargers in use at once.
• Practical build. Parse the session feed, rejecting bad rows with reasons.
• Someone else’s code. Fix why drivers get two “charging complete” texts.
• AI-assisted. Build an idle-car reminder with an assistant.
• Data. Find each station’s weekly share of failed sessions.

The algorithm version:

from collections import Counter

def busiest(events):
    # events: (minute, station, d)
    # with d = +1 plug, -1 unplug.
    # Unplugs sort first at a tie.
    now = Counter()
    peak = Counter()
    for t, s, d in sorted(events):
        now[s] += d
        if now[s] > peak[s]:
            peak[s] = now[s]
    return max(peak, key=peak.get,
               default=None)

Say aloud: “Sort, then one sweep: O(n log n) time, and O(n) space for the sorted copy. At a tie I free the charger first, so a same-minute swap is not two cars.” Naming your edge case is what this round rewards, in our reading.

In a practical round, say what the algorithm round let you skip: “Is every unplug matched by a plug? A car plugged in before midnight drives the count below zero.”

Google’s candidate reports run from LeetCode hard to none:

• L4, July 2026: one candidate on Blind described “roughly LeetCode Medium difficulty”, “presented as a real-world scenario”. ^{[2, 3, 4]}Source 2FDE Interview Experience at Google (L4) (Blind)PublisherBlindSource typecandidate report on BlindSource 3Is Google FDE interview same as SWE? (Blind)PublisherBlindSource typecandidate report on BlindSource 4Google Forward Deployed Engineer Interview Experience (Blind)PublisherBlindSource typecandidate report on Blind
• GenAI, May 2026: one poster on Blind wrote “leetcode medium hard”, and feedback that named a level: “Hire for L4, not for L5”. ^[5]Source 5Google Rejected for FDE. Need immediate referralPublisherBlind (teamblind.com)Source typecandidate report on Blind
• Applied AI, May 2026: in a thread on the role, one commenter, naming no company, reported an onsite LC hard. ^[6]Source 6Google Forward deployed Engineer (comment by u/Inevitable_Clue_9877)PublisherReddit r/leetcodeSource typecandidate report on Reddit
• Cloud AI L5, August 2026: one poster on Blind reported no LeetCode, but a real-scenario question about streaming. ^{[7, 8]}Source 7Google FDE vs Remain Amazon SDEPublisherBlind (teamblind.com)Source typecandidate report on BlindSource 8Google L5 FDE vs Remain Amazon L5 SDEPublisherBlind (teamblind.com)Source typecandidate report on Blind

Google’s published policy says AI tools are not permitted during interviews. ^[9]Source 9Our hiring process - Google CareersPublisherGoogleSource typecompany hiring page

Company by company: published, then reported

Weigh the reports as the evidence map sets out; where a commenter names no company, the thread names it. One target, in full:

C3 AI. Its careers page says a coding challenge or a written assignment and presentation may follow the initial screen. ^[10]Source 10Careers | C3 AIPublisherC3 AISource typecompany job posting That names a step, not a kind. Three candidates reported on Reddit, in August 2026, algorithm rounds for C3 AI FDE roles: hash maps, a sliding window with a hash map, and a stack-based sliding window. ^{[11, 12, 13, 14]}Source 11C3 AI Senior Forward Deployed Engineer (FDE) Interview Process – My Experience (post by u/Wrong_Classic_7306)PublisherReddit r/OfferEngineeringSource typecandidate report on RedditSource 12C3 AI Senior Forward Deployed Engineer (FDE) Interview Process – My Experience (comment by u/Wrong_Classic_7306)PublisherReddit r/OfferEngineeringSource typecandidate report on RedditSource 13C3 AI - Forward Deployed Engineer interview process (comment by u/BalanceOdd144)PublisherReddit r/leetcodeSource typecandidate report on RedditSource 14C3 AI Senior Forward Deployed Engineer (FDE) Interview Process – My Experience (comment by u/speedy_string)PublisherReddit r/OfferEngineeringSource typecandidate report on Reddit In a C3 AI Senior FDE thread, one commenter reported, in September 2026, a one-hour round with “very vague requirements and output expectations”. ^{[15, 16]}Source 15C3 AI Senior Forward Deployed Engineer (FDE) Interview Process – My Experience (comment by u/becquerwrecker)PublisherReddit r/OfferEngineeringSource typecandidate report on RedditSource 16C3 AI Senior Forward Deployed Engineer (FDE) Interview Process – My Experience (comment by u/becquerwrecker)PublisherReddit r/OfferEngineeringSource typecandidate report on Reddit The verdict:

Target:    C3 AI, FDE
Published: coding challenge or
           written assignment may
           follow the screen
           (careers page)
Reported:  3 candidates, Aug 2026,
           after the round: hash
           map; window + hash map;
           stack sliding window.
           1 commenter, Sep 2026:
           vague 1-hour problem
Kinds:     algorithm + vague build
AI rule:   ask
This week: window, vague

Drill the longest unique window and vague requirements, where asking is the work.

Palantir. Its published interview competencies include Writing Good Code, Analyzing the Efficiency of Code and Working Inside Existing Systems, and its guide names Forward Deployed Software Engineers among those who need to understand quality code. ^{[17, 18]}Source 17Palantir Careers | Getting HiredPublisherPalantirSource typecompany hiring pageSource 18Writing Good CodePublisherPalantirSource typecompany hiring page Blind threads on its software and FDSE interviews, from June 2022 to March 2025, mention LeetCode-style problems, one recalled from about six years before. ^{[19, 20]}Source 19Anyone done a Palantir SWE/Forward Deployed SWE interview recently? (Blind)PublisherBlindSource typecandidate report on BlindSource 20Palantir FDSE Interview (Blind)PublisherBlindSource typecandidate report on Blind A Government-track candidate reported a Python object-oriented design screen in December 2025. ^[21]Source 21Palantir FDSE Full Interview Loop Process (post by u/Not_the_Sauron)PublisherReddit r/csMajorsSource typecandidate report on Reddit Verdict: algorithm and object-oriented screens, older reports weighed least; we found no Palantir rule on AI in a live round, so ask.

Anthropic. Its careers page names CodeSignal among its live coding tools. ^[22]Source 22CareersPublisherAnthropicSource typecompany hiring page Three Blind posters wrote of its CodeSignal assessment in 2024, one for a Solutions Architect/Forward Deployed Engineer role: two “maybe leetcode easy level” questions in 60 minutes, “no algo involved”, and “a speed test”. ^{[23, 24, 25, 26]}Source 23Anthropic Solutions Architect/Forward Deployed Engineer CodesignalPublisherBlind (teamblind.com)Source typecandidate report on BlindSource 24Anthropic CodeSignal problem (Blind)PublisherBlindSource typecandidate report on BlindSource 25Anthropic CodeSignal interview (Blind)PublisherBlindSource typecandidate report on BlindSource 26Anthropic's Interview Process & QuestionsPublisherinterviewing.ioSource typeinterview prep site Verdict, from reports over two years old: a speed test, light on algorithms; confirm it. Its guidance for live interviews is no AI assistance unless Anthropic indicates otherwise. ^[27]Source 27Guidance on Candidates' AI UsagePublisherAnthropicSource typecompany website

OpenAI. For engineering interviews, its guide looks for “well-designed solutions to the challenge, high-quality code, optimal performance, and good test coverage”, and says AI expectations vary by interview. ^{[28, 29]}Source 28Interview Guide | OpenAIPublisherOpenAISource typecompany hiring pageSource 29OpenAI interview guide (Wayback Machine capture)PublisherOpenAI (archived by Internet Archive)Source typearchived company page Before any round, a Blind poster for its Forward Deployed SWE role wrote, in April 2026, that the recruiter said the interviews were “not leetcode”. ^[30]Source 30OpenAI Forward Deployed SWE RolePublisherBlind (teamblind.com)Source typecandidate report on Blind One candidate’s report on Aced, interview month May 2026, describes an AI-enabled coding screen for an OpenAI FDE role that they called an easy LeetCode problem. ^[31]Source 31OpenAI Forward Deployed Engineer Interview ExperiencePublisherAced (formerly Exponent)Source typecandidate’s personal write-up Verdict: the report from after the round outweighs a recruiter’s word before it; drill a light algorithm problem with an assistant, and ask.

Cohere. A Blind poster asking for a friend wrote, in September 2026, that the recruiter said of a Cohere FDE coding round, “they give you an existing python codebase and ai”; a 2024 poster’s recruiter had called theirs “not like a leet code”. ^{[32, 33]}Source 32Cohere coding interview (Blind)PublisherBlindSource typecandidate report on BlindSource 33Cohere FDE onsite, AI enabled coding round? (Blind)PublisherBlindSource typecandidate report on Blind Verdict: someone else’s Python, with an assistant; confirm it.

Enterprise and data companies

Check published AI rules against reports, and drill SQL.

Snowflake. Snowflake’s careers blog said, in January 2026, that all candidates do coding interviews without coding or AI assistants. ^[34]Source 34AI Cheat Sheet: How (and When) to Use AI in Your Snowflake InterviewPublisherSnowflake CareersSource typecompany hiring page One candidate for its Senior Forward Deploy Engineer, Spark role wrote on Blind, in May 2026, that “you can use AI but they ask to provide a note on how it’s used”. ^[35]Source 35Snowflake Senior Forward Deploy Engineer - Spark (Blind)PublisherBlindSource typecandidate report on Blind Blog and report disagree, so ask in writing.

Databricks. One candidate’s report on Aced for an L3 Databricks FDE role, interview month February 2026, with an offer, lists a rapid-fire technical screen and a separate practical coding round. ^[36]Source 36Databricks Forward Deployed Engineer Interview ExperiencePublisherAced (formerly Exponent)Source typecandidate’s personal write-up A candidate for its AI FDE role wrote, in August 2026, before interviewing, that they were told the coding round focuses on applied data science and traditional machine learning. ^{[37, 38]}Source 37Anyone been through interviews for AI FDE at Databricks ? (post by u/Haunting_Ad3263)PublisherReddit r/cscareerquestionsukSource typecandidate report on RedditSource 38Anyone been through interviews for AI FDE at Databricks ? (comment by u/Haunting_Ad3263)PublisherReddit r/cscareerquestionsukSource typecandidate report on Reddit Verdict: practical, perhaps data science; ask.

Salesforce. In an Agentforce FDE thread, one commenter reported, in August 2026, an assessment with a simple string task and basic SQL. ^[39]Source 39Forward Deployed Engineer (Agentforce) (comment by u/joemons)PublisherReddit r/SalesforceCareersSource typecandidate report on Reddit Verdict: easy code and plain SQL; confirm it.

A data round rewards checking the key before counting, as in the EV failure share:

SELECT session_id, count(*)
FROM sessions
GROUP BY session_id
HAVING count(*) > 1;

Rows come back: reconnects repeat sessions. Keep each latest row, then count:

WITH latest AS (
  SELECT DISTINCT ON (session_id)
         station_id, started_at,
         status
  FROM sessions
  ORDER BY session_id,
           updated_at DESC
)
SELECT
  station_id,
  date_trunc('week', started_at)
    AS week,
  avg((status = 'failed')::int)
    AS failed_share
FROM latest
GROUP BY 1, 2
ORDER BY 1, 2;

Say aloud: “A reconnect repeats a session, so I kept each session’s latest row; counting every row would count one session twice.” SQL and data for FDEs goes deeper.

Practical builds, in stages

In our reading, a practical build is won at the seams between parts. In a July 2026 Blind thread titled “Scale AI Interview”, a poster, naming no role, wrote “it says the first technical screen is not Leetcode style but more practical, with three parts”. ^[40]Source 40Scale AI InterviewPublisherBlindSource typecandidate report on Blind One commenter there, naming no company or role, reported from “a while ago” three parts on one problem: build it, extend it with new requirements, then discuss scaling or edge cases. ^[40]Source 40Scale AI InterviewPublisherBlindSource typecandidate report on Blind

The EV feed’s first part:

import csv
from datetime import datetime

NEED = ("station", "start", "kwh")
iso = datetime.fromisoformat

def parse(r):
    for k in NEED:
        if not r.get(k):
            why = "missing " + k
            return None, why
    try:
        t = iso(r["start"])
        kwh = float(r["kwh"])
    except ValueError as e:
        return None, str(e)
    if kwh < 0:
        return None, "kwh < 0"
    rec = (r["station"], t, kwh)
    return rec, None

def load(f):
    good, bad = [], []
    rows = csv.DictReader(f)
    for r in rows:
        rec, why = parse(r)
        if why:
            n = rows.line_num
            bad.append((n, why))
        else:
            good.append(rec)
    return good, bad

Each bad row keeps its line and reason. Moving to part two, say: “I’ll run what I have on the sample first, so the new rule starts from green.” At part three: “If the file outgrows memory, I’d yield clean rows instead of keeping a list.” The full model answer is in messy CSV.

Unfamiliar-code rounds

When the code is someone else’s, reproduce the bug with a failing test before you read the whole file, then fix and rerun. Palantir’s guide to working inside existing systems says “a developer will spend far more time debugging, modifying, and extending existing code than writing brand-new things.” ^[41]Source 41Working Inside Existing SystemsPublisherPalantirSource typecompany hiring page

The EV double texts come from here:

class Notifier:
    def __init__(self, send):
        self.send = send
        self.seen = set()

    def on_complete(self, ev):
        key = ev["event_id"]
        if key in self.seen:
            return
        self.seen.add(key)
        self.send(ev["driver"])

Write the test first:

def test_one_text_per_session():
    texts = []
    n = Notifier(texts.append)
    for eid in ("e1", "e2"):
        n.on_complete({
            "event_id": eid,
            "session": "s9",
            "driver": "d1",
        })
    assert texts == ["d1"]

It fails with ['d1', 'd1']; key on ev["session"] and it passes. As you go, say: “Two complete events for one session should send one text. It fails with two: we dedupe on the event, but a reconnect sends a new event for the same session. I’ll key on the session, rerun, then check where else we dedupe on event ID.”

Take the unfamiliar bug question and reproduce a bug with a test; the module Screens and unfamiliar code goes further.

AI-assisted coding as a round format

With an assistant in the room, the skill is scoping and judging.

In an April 2026 post about its engineering interviews generally, not an FDE loop, Sierra says it replaced coding and algorithms interviews with an AI-native onsite: Plan, Build (two hours, with AI tooling of the candidate’s choice) and Review. ^[42]Source 42The AI-native interview (Vijay Iyengar, Arya Asemanfar, Angie Wang)PublisherSierraSource typecompany blog It is also piloting a debugging interview: improving a colleague’s draft PR in a medium-sized codebase with coding agents. ^[42]Source 42The AI-native interview (Vijay Iyengar, Arya Asemanfar, Angie Wang)PublisherSierraSource typecompany blog

One candidate wrote on Aced, of a June 2026 Stripe FDE interview, that the coding round “explicitly allowed AI, but they seemed to care much more about whether I could break work down, steer the model, and review it critically”. ^[43]Source 43Stripe Forward Deployed Engineer Interview ExperiencePublisherAced (formerly Exponent)Source typecandidate’s personal write-up For the EV idle-car reminder, that review sounds like: “I’m keeping the assistant’s parser but replacing its per-car sleep loop with one scheduled check a minute. It missed a car that unplugs during the grace period, so I’ll add that test first.”

Our reading: do each practical drill alone, then with an assistant. Check each round’s rule in AI rules by company and stage, then take the existing-codebase question.

Same bar as software engineers

At some employers the FDE coding bar is the software engineer’s. Leo Mehr, Director of Engineering at Ramp, said on the dearCC podcast, in June 2026, that Ramp’s FDE candidates must pass the software engineering loop. ^[44]Source 44What is a Forward Deployed Engineer? (FDE Explained) feat. Leo Mehr of Ramp (YouTube auto-generated English captions)PublisherdearCC (Clara Shih), YouTubeSource typerecorded talk or interview Baseten’s FDE lead writes that every FDE candidate must pass its standard technical bar plus a product intuition screen. ^[45]Source 45Forward deployed engineering on the frontier of AIPublisherBasetenSource typecompany blog Sarah Khalid, an FDE Director at Salesforce, called coding “table stakes” in its newsroom in March 2026. ^[46]Source 46How Forward Deployed Engineers Are Proving AI Makes Tech Jobs More HumanPublisherSalesforce NewsroomSource typecompany blog

Mehr also wrote on Ramp’s blog, in August 2025, that some candidates who did just okay in coding interviews turned out to be incredible FDEs. ^[47]Source 47Forward Deployed Engineering (Leo Mehr, Director, Engineering)PublisherRamp Builders (engineering blog)Source typecompany blog On Lenny’s Podcast, YouTube edition, in May 2025, Nabeel Qureshi, a former Palantir FDE, said one of Palantir’s two FDE types got a technical interview “more about just like can you reason about data”. ^[48]Source 48How Palantir built the ultimate founder factory | Nabeel S. Qureshi (YouTube uploaded en-US captions)PublisherLenny's Podcast, YouTubeSource typerecorded talk or interview Our reading: clear the bar; the customer side is added, not traded.

A drill plan for your targets

Our verdict template puts each target on one card:

Target:    company, exact title
Published: what its pages say
Reported:  who, when, which role,
           before or after round
Kinds:     algorithm / build /
           their code / assisted /
           data
AI rule:   published, reported
           or ask
This week: the drill pairs

Still unsure of the kind? Ask the recruiter in writing: “Will the coding round start from a blank editor, existing code or a dataset? Is it one problem, or one that grows? Can I run code, and is an AI assistant allowed?” In the room, first minute: “Before I start: can I run this, will it grow, and should I use an assistant?”

Match drills to the kind; the object-oriented and streaming rows follow one candidate report each, from Palantir and Google. ^{[7, 8, 21]}Source 7Google FDE vs Remain Amazon SDEPublisherBlind (teamblind.com)Source typecandidate report on BlindSource 8Google L5 FDE vs Remain Amazon L5 SDEPublisherBlind (teamblind.com)Source typecandidate report on BlindSource 21Palantir FDSE Full Interview Loop Process (post by u/Not_the_Sauron)PublisherReddit r/csMajorsSource typecandidate report on Reddit

Our rule of thumb: when reports disagree or are missing, pair one practical drill with one algorithm problem per session, timed.

Take Sam, a fictional candidate: Target A’s reports show algorithm and object-oriented screens; Target B’s, a debugging round and an assisted one. Sam pairs one drill per target daily, adds the assistant from Tuesday and ends cold:

Target A: algorithm + OOD
  AI rule: none (asked recruiter)
Target B: their code + assisted
  AI rule: one round allows it

Mon  algorithm, 30 min, cost aloud
     + bug hunt in unfamiliar code
Tue  class model, new requirement
     + same bug, with assistant
Wed  algorithm, no code runs
     + extend their code with AI
Thu  class model, 45 min
     + name the assistant's errors
Fri  one problem, one bug, cold
     + rewrite both verdicts

Your move now: write one verdict line per target today. Then run messy CSV on a timer and the unfamiliar bug right after, narrating; the kind that runs over is where your week starts.

Keep going. Every question shows its framework free; the token bucket, messy CSV, log latency, refactoring, mini RAG and SQL questions above add model answers. Pro opens the other model answers, the double bar, AI rules by company and stage and this module’s other lessons.