By FDE Interview Prep, a SourceStrongAI company

In this post12 sections
  1. Where your sales engineering skills score
  2. Some FDE roles are closer to your job than you think
  3. The first gap: the coding round
  4. The second gap: stories that end at the signature
  5. Reframing quota stories as delivery stories
  6. Which rounds to drill, in order
  7. What to say about leaving a commission plan
  8. Common mistakes when moving over
  9. Start with the coding questions
  10. Questions people ask
  11. Keep reading
  12. More from the blog

You already have the customer half of the bar: you can run a discovery call, save a demo when the sandbox dies, and explain an architecture to a finance lead and a staff engineer in the same meeting. What you have been tested on least is the other half: a coding round, and behavioral questions about what happened after the contract was signed. Yes, you can make the move. LangChain’s Deployed Engineer posting, which has you co-build production AI agents with customer engineering teams, counts solutions engineering as relevant technical experience. Source 1Deployed Engineer (Bay Area) @ LangChainPublisherLangChain (Ashby job board)Source typecompany job posting If you are still deciding whether FDE is the job you want, start with our guide to forward deployed engineer vs sales engineer.

You have two gaps to close: the coding bar, and stories that end at the signature. This post assumes you have decided, and shows you how to get through the loop, with the words to use.

Where your sales engineering skills score

Your skills do transfer, but each one scores in a specific round. Know where, so you can point to it:

  • Discovery scores in the customer round. Finding out what a customer means, not just what they said, is the core of it. The one habit to drop there is saying yes; there is a worked exchange below.
  • Demos under pressure score in a demo stage, where one exists. Roboflow’s FDE posting lists a demo in which the candidate builds a project with Roboflow and shares the work, beside a technical assessment of live coding or architecture. Source 2Forward Deployed Engineer @ RoboflowPublisherRoboflow (Ashby job posting)Source typecompany job posting You build with their product, then show it; a slide deck will not carry it.
  • Objection handling scores in the behavioral round, if you tell it from the engineering side. When sales promised what you cannot deliver is the question built for it.
  • Proofs of concept on data you did not choose are the start of the “their data, messy” habit the coding round looks for (see the table below).

Now the other side. Jia Wu, a deployed engineering lead at Cognition, said at the AI Engineer World’s Fair in a talk posted in July 2026 that business sense can be learned, while being the technical expert in the room is very hard to teach. Source 3How Forward Deployed Engineering is done at Cognition (Jia Wu; AI Engineer World's Fair 2026)PublisherAI EngineerSource typerecorded talk or interview At Cognition, at least, business sense is treated as the teachable part; the technical depth is what you have to prove.

Some FDE roles are closer to your job than you think

Before you drill anything, read the posting, because “forward deployed engineer” does not mean one job. Three postings show the spread:

  • Modal’s Stockholm “Forward Deployed Engineer - Systems” posting describes the technical voice in the sales process, working with account executives, and asks for 5+ years in solutions engineering, sales engineering or customer-facing technical roles. Source 4Forward Deployed Engineer - Systems @ Modal (Stockholm)PublisherModal (Ashby)Source typecompany job posting That is close to sales engineering with an FDE title. It can be a good job, but it is not the move you are trying to make.
  • LangChain’s Deployed Engineer sits in the middle: it owns the technical win in pre-sales by designing proofs of concept, and also co-builds production AI agents with customer engineering teams. Source 1Deployed Engineer (Bay Area) @ LangChainPublisherLangChain (Ashby job board)Source typecompany job posting
  • Cursor’s FDE postings say FDEs embed with customer engineering teams to ship production-grade workflows, and state: “This is not a demo role.” Source 5Forward Deployed EngineerPublisherCursor (Ashby job board)Source typecompany job board

So read three lines of every posting before you prepare:

  1. Who you work with. Account executives, or customer engineering teams?
  2. What you own after the signature. The relationship, or a system in production?
  3. The pay line. Base salary, or (OTE)?

Pay basis alone does not decide it: LangChain’s Deployed Engineer role, which co-builds production agents, states its pay as OTE. Source 1Deployed Engineer (Bay Area) @ LangChainPublisherLangChain (Ashby job board)Source typecompany job posting Weigh the first two lines first, then ask what the variable part is measured on; our post on why some FDE jobs pay OTE explains how. If the answers are “account executives” and “the relationship”, that is closer to the job you have now; prepare for it as that job. If the posting has you owning both the proof of concept and the production build, as LangChain’s does, read where pre-sales FDE work stops being engineering.

To practice on real posting lines, work the classification exercise in our free lesson on telling FDE, SA, SE and SWE postings apart.

The first gap: the coding round

Expect to be tested as an engineer. Leo Mehr, Director of Engineering at Ramp, said on a podcast published in June 2026 that FDE candidates at Ramp face the same technical bar and must pass the software engineering interview loop. Source 6What 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 OpenAI’s San Francisco FDE posting asks for people who write and review production-grade code. Source 7Forward Deployed Engineer (FDE) - SFPublisherOpenAI (Ashby)Source typecompany job posting Whether you can use an AI assistant depends on the employer. Anthropic’s guidance for live interviews is no AI assistance unless it says otherwise, Source 8Guidance on Candidates' AI UsagePublisherAnthropicSource typecompany website while OpenAI’s interview guide says some formats allow AI tools and others do not. Source 9Interview guidePublisherOpenAISource typecompany hiring pageSource 10OpenAI interview guide (Wayback Machine capture)PublisherOpenAI (archived by Internet Archive)Source typearchived company page

Demo code and production code look alike and are written with different habits. Here is the difference, as we teach it:

Demo habitProduction habit
Happy path onlyEvery failure has a path
Sample data you choseTheir data, messy
Runs once, while you watchRuns every night, and resumes
You explain itTests explain it
Key pasted in the scriptConfig and secrets kept apart

A coding round is built to find out which habits you have. Take a practical task: pull every record from a paged API that rate-limits and sometimes fails. The demo version is one line, requests.get(url).json()["items"], and it works on stage. The production version looks more like this:

import random, time

RETRYABLE = {429, 500, 502, 503, 504}

def get_page(session, url, cursor,
             tries=5):
    for attempt in range(tries):
        r = session.get(
            url, params={"cursor": cursor},
            timeout=10)
        if r.status_code not in RETRYABLE:
            # other 4xx: fail now
            r.raise_for_status()
            return r.json()
        if attempt < tries - 1:
            ra = r.headers.get("Retry-After")
            wait = float(ra or 2 ** attempt)
            time.sleep(wait + random.random())
    raise RuntimeError(
        f"gave up at cursor {cursor!r}")

def fetch_all(session, url, cursor=None):
    seen = set()
    while True:
        page = get_page(session, url, cursor)
        for item in page["items"]:
            # pages can overlap
            if item["id"] not in seen:
                seen.add(item["id"])
                yield item
        cursor = page.get("next_cursor")
        if not cursor:
            return

The code is not the point. The point is the reasoning you say out loud while you write it: rate limits and server errors are retried with backoff and ; a bad request fails at once, because sending it again changes nothing; a late failure retries that page, not the whole run; duplicates across pages are dropped; there is no pointless sleep after the last try; and the error names the cursor, so tomorrow’s run starts there. A real client also handles timeouts that raise, and a Retry-After sent as a date, which RFC 9110, section 10.2.3 allows. Naming what you left out is part of a strong answer.

To practice, work the flaky API integration question, then read our post on the API integration coding round for retries, pagination and idempotency in depth. Our free lesson on what FDE coding rounds test sets out, company by company, whether reports point to algorithm problems, practical builds or someone else’s code, so you drill the right thing.

The second gap: stories that end at the signature

If your stories end with “and we won the deal”, they stop where the FDE job starts. In our method, every story you bring to an FDE loop should end in production. Here is one rewritten.

Before:

“I was the technical lead on our biggest deal of the year. My proof of concept won the technical evaluation against two competitors, and the customer signed.”

After:

“The customer needed claim notes pulled from a document system with no API. I wrote the export against their file drop and tested the classifier on their real notes, not our samples. That’s how I found it failed on scanned handwriting. I told the account executive before the contract, we cut scans from the first release, and I stayed on through rollout and ran support for the first month. The claims team still uses it; the scans came in the second release.”

The second version shows four things we train for:

  1. You worked in their environment, on their data, not a sandbox.
  2. You found the failure yourself, before the customer did.
  3. You protected scope under sales pressure, and said so to the person who owned the deal.
  4. You owned the result after the signature.

If you have no story that goes past the signature, build one now. Pick a past deal and find out what happened to it: ask the customer’s champion, or the implementation team. Or ship a small integration end to end on your own and run it for a few weeks.

Reframing quota stories as delivery stories

Most of your best material is in deals. You do not have to throw it away. You have to change what the story is about. Rewrite each story line by line, swapping the sales line for the delivery line:

Quota story saysDelivery story says
“We won the technical evaluation”“Here is what I built, and on whose data”
“I handled the objection”“Here is what I checked to answer it”
“The deal closed”“Here is what I cut to ship on time”
“I hit my number”“Here is what still runs, and who uses it”

Your quota attainment can stay in the story. Move it to the last line, as context, not the headline.

The lost deal is often your strongest story. The time you told the account executive that the product could not do what the customer needed, and the deal slipped or died, shows the judgment an FDE needs. Tell it with the technical detail: what you tested, what broke, what you told whom, and what you proposed instead.

Here are words that work when an interviewer asks why your stories come from sales:

“My job put me in front of the customer before the contract, so that’s where most of my building happened. The part I’m proudest of is the technical call I made in those builds. Let me tell you about the time the proof of concept failed on their real data, and what I did about it.”

Practice the rewritten stories against two questions. The end-to-end ownership question checks whether a story reaches production. When sales promised what you cannot deliver asks about the handoff from the side you know best: you have been in the room when the promise was made. A strong answer names the promise, what you checked, the trade you offered and what you changed so it would not happen again.

Which rounds to drill, in order

This order is ours. It puts your time where your background has been tested least, and leaves your strengths for last.

A practice order for sales engineers

  • Practical coding, daily. Build small things against APIs and messy data, with tests, on a timer, mostly without an assistant, and once a week with one, since some loops allow it.
  • Behavioral stories. Rewrite your top stories with the table above and say each one out loud.
  • Scoping and design. Turn a vague request into a first version you would ship, and name what it leaves out.
  • The customer round. You are strong here. Drill the one habit to drop: saying yes.
  • The “why FDE” answer. Tie it to one thing you built, then rehearse the follow-ups.

The customer round deserves a note. The sales reflex is to keep the customer happy by agreeing. In our method, the strong move is to scope a first version and say plainly what it will not do yet. Here is the difference, using the claims project from the story above:

Customer: “Can it also handle our scanned forms by launch?”

Sales reflex: “Yes, we can make that work.”

FDE move: “Not in the first version. Scans failed on your real notes when I tested them. What I can ship by launch is typed notes end to end, and I’ll show you scan accuracy on a sample of your own forms before we commit to them.”

The second answer says no to the scope, gives the evidence, and offers a next step the customer can hold you to. Our free lesson on what customer rounds look like covers the core moves. Then try one live in the free practice case. It puts you in a live customer conversation with an AI customer who holds back facts until you ask the right questions.

For “why FDE”, our free lesson on the bridge story and the short “why FDE” answer shows how to connect your past work to the job in two minutes. Rehearse it against the “why FDE and not software engineering?” question; the follow-ups are the same shape when the other job is sales engineering.

What to say about leaving a commission plan

Someone in the loop may ask, directly or not, whether you will miss the upside. Treat it as a question about whether you will drift back toward the deal.

There is a reason for that worry. An Andreessen Horowitz essay on forward deployed teams observes that implementation leads rarely want to carry a quota, and that a quota can lead to counterproductive behavior. Source 11Trading Margin for Moat: Why the Forward Deployed Engineer Is the Hottest Job in StartupsPublisherAndreessen HorowitzSource typeindependent analysis The essay does not name the behavior. The one that matters in an FDE loop, in our view, is promising scope to close.

Do not say you are “leaving sales”. Some FDE roles still help win deals, as LangChain’s does. Say what you are moving toward:

“I’ve been paid on whether the customer signs. I want to be measured on whether the thing still works long after launch. That’s the part I kept wanting to stay for.”

Then ask your own question about pay structure, because some FDE postings state pay as on-target earnings. Okta’s Principal FDE posting, for one, gives an OTE range that includes base salary and incentive compensation. Source 12Principal Forward Deployed Engineer - Okta for AI AgentsPublisherOkta (Greenhouse)Source typecompany job posting Ask it in these words: “Is the range base or OTE, and if OTE, what is the variable part measured on?” An answer tied to bookings means the role is closer to the one you have now.

Common mistakes when moving over

  • Leading with quota attainment. It proves you can sell. Lead with what you built, then mention the deal.
  • Calling the move “leaving sales”. Frame it as staying on after the sale.
  • Skipping the coding practice. Your customer skills will not carry a failed coding round.

Start with the coding questions

Tonight, give half an hour to the flaky API integration question: build it without an assistant, say every failure path out loud, then check yourself against the framework. Tomorrow, rewrite one deal story with the table above and run it against the end-to-end ownership question. Every question in the bank of 180 shows its framework free, and Pro, which starts with a 7-day free trial, includes the model answers.

GlossaryForward deployed engineerA software engineer who builds and ships production systems inside a customer’s problem and environment, accountable to that customer’s outcome.More on Forward deployed engineerGlossaryOn-target earningsBase pay plus variable pay if targets are met; a posting that states pay as OTE includes incentive pay in the figure.More on On-target earningsGlossaryExponential backoff with jitterRetrying with growing, randomized delays so that clients recovering from the same failure do not retry in lockstep.More on Exponential backoff with jitter

Questions people ask

Can a sales engineer become a forward deployed engineer?

Some FDE postings ask for that background. LangChain’s Deployed Engineer posting counts solutions engineering as relevant experience, and Modal’s Stockholm FDE posting asks for experience in solutions engineering, sales engineering or customer-facing technical roles. Expect a coding bar and questions about what you shipped after the deal.Source 1Deployed Engineer (Bay Area) @ LangChainPublisherLangChain (Ashby job board)Source typecompany job postingSource 4Forward Deployed Engineer - Systems @ Modal (Stockholm)PublisherModal (Ashby)Source typecompany job posting

Will a sales engineer face a coding round in an FDE interview?

Plan on it. Leo Mehr, Director of Engineering at Ramp, said in June 2026 that FDE candidates at Ramp face the same technical bar and must pass the software engineering interview loop. OpenAI’s FDE posting asks for people who write and review production-grade code.Source 6What is a Forward Deployed Engineer? (FDE Explained) feat. Leo Mehr of Ramp (YouTube auto-generated English captions)PublisherdearCC (Clara Shih), YouTubeSource typerecorded talk or interviewSource 7Forward Deployed Engineer (FDE) - SFPublisherOpenAI (Ashby)Source typecompany job posting

Do FDE interviews include a demo?

Some do. Roboflow’s FDE posting lists a demo in which the candidate builds a project with Roboflow and shares the work, beside a technical assessment of live coding or architecture. A demo stage does not replace the coding bar, so prepare for both.Source 2Forward Deployed Engineer @ RoboflowPublisherRoboflow (Ashby job posting)Source typecompany job posting

What is the hardest part of moving from sales engineering to FDE?

In our view, the coding round. Leo Mehr, Director of Engineering at Ramp, said in June 2026 that FDE candidates at Ramp must pass the software engineering interview loop, and demos and proofs of concept rarely practice that. The second gap is stories: interview stories that end when the contract is signed stop where the FDE job starts.Source 6What 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

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