The FDE interview glossary
The words interviewers and lessons use, each defined in a sentence, with the lesson that teaches it.
A
- Agent
- A system in which a model chooses steps and tool calls to complete a task, within limits the design sets.
B
- Backfill
- Reprocessing historical data through a pipeline, ideally with the same idempotent code as the daily run.
- Backpressure
- A signal from a slow consumer that makes a producer slow down instead of overflowing memory or queues.
- Bridge story
- A short account that connects your past work to FDE work by naming a customer, what you built for them and what changed.
C
- Calibrated commitment
- A promise limited to what you control, with an owner, a date and the conditions stated for everything else.
- Canary release
- Sending a change to a small share of traffic and watching agreed metrics before rolling it out to everyone.
- Circuit breaker
- A pattern that stops calling a failing dependency for a while, then probes it, so failures do not cascade.
D
- Data lineage
- A record of where each piece of data came from and how it was transformed, so any number can be traced to its source rows.
- Data residency
- A requirement that data, including logs and backups, be stored and processed in a specific region.
- Dead-letter queue
- A holding place for messages that failed processing too many times, kept for inspection and replay.
- Decomposition round
- An open-ended interview in which you work out loud from a vague problem with several possible solutions to a concrete approach and a first working version.
- Deployment strategist
- A customer-facing role that works out the customer’s questions and scope beside FDEs; at some employers the title means a product-manager or quota-carrying role instead.
E
- Embedding
- A vector representation of text or other data used to measure similarity of meaning.
- Exponential backoff with jitter
- Retrying with growing, randomized delays so that clients recovering from the same failure do not retry in lockstep.
F
- FedRAMP
- The US government program that assesses and certifies a cloud service at an impact level before federal agencies may put their data in it.
- Forward deployed engineer
- A software engineer who builds and ships production systems inside a customer’s problem and environment, accountable to that customer’s outcome.
- Forward deployed software engineer
- Palantir’s title for its FDE role, called Delta internally; OpenAI and EY also post FDSE titles, each with its own duties.
G
- Gaps and islands
- A SQL pattern for finding continuous runs, and the breaks between them, in ordered data such as machine status.
- GDPR
- The EU regulation governing the processing and transfer of personal data.
- Golden set
- A curated, labeled set of examples, sampled to cover the cases that matter, used to evaluate a system the same way over time.
- Guardrail metric
- A metric watched alongside the success metric to catch harm or gaming, such as wait times by district when the target is the average.
H
- H-1B labor condition application
- A US filing that states the base wage, as a rate or a range, an employer will pay a sponsored worker in a job; it records no bonus or equity.
- HIPAA
- The US law whose Privacy and Security Rules govern protected health information and the vendors that handle it.
- Hybrid search
- Combining keyword and vector retrieval and merging their ranked results, for example with reciprocal rank fusion.
I
- Idempotency key
- A client-supplied identifier that lets a server apply a repeated request once, making retries safe.
- Inter-rater agreement
- How consistently two reviewers, or a reviewer and a model judge, label the same items, corrected for agreement by chance.
L
- Latency budget
- The total time a request may take, divided among the steps it passes through, measured at the slow tail as well as the median.
- Launch criteria
- Thresholds agreed with a customer before building that decide whether a system goes live.
- LLM-as-judge
- Using a language model with a rubric to grade outputs; the judge itself must be checked against human labels.
M
- Model Context Protocol
- An open protocol for exposing tools and data to models through servers, so agents can call a customer’s systems in a standard way.
O
- OAuth
- A standard for granting an application limited, revocable access to resources on a user’s behalf without sharing passwords.
- On-target earnings
- Base pay plus variable pay if targets are met; a posting that states pay as OTE includes incentive pay in the figure.
- Ontology
- A shared model of a customer’s business objects and their relationships, mapped onto the underlying data so people and applications use the same terms.
- OpenID Connect
- An identity layer on top of OAuth that lets an application verify who a user is and get basic profile claims.
- Ownership audit
- Rewriting a story so every decision has a named owner: what you decided and did, and what others did, credited to them.
- Ownership language
- Phrasing that names who acts, what they will do and by when, owning your part without blaming others or claiming control you lack.
P
- Personal data
- Information that identifies a person or can be linked to one, which privacy law and customer policy restrict.
- Problem shape
- A recurring structure of customer problem, such as unifying fragmented sources, that looks the same across industries.
- Profit participation unit
- A grant that pays a share of a company’s future profit distributions instead of stock, with no shareholder vote.
- Prompt injection
- Input that tries to override a model’s instructions, directly or hidden in retrieved documents, emails or tool results.
Q
- Query plan
- The steps a database chooses to run a query, read with EXPLAIN to find scans, joins and missing indexes.
R
- Re-engineering round
- An interview in which you learn, debug or extend code or a library you have never seen, against the clock and out loud.
- Regression suite
- Cases rerun on every prompt, model or code change to catch behavior that used to work and now does not.
- Reranking
- Re-scoring a short list of retrieved results with a slower, more accurate model before they reach the prompt.
- Retrieval-augmented generation
- Answering with a model that is given passages retrieved from a document collection as context.
S
- Sales engineer
- A technical role on or beside a sales team that helps win deals with demos and proofs of concept; the U.S. Bureau of Labor Statistics says employers usually pay it salary plus commissions or bonuses.
- SAML
- An XML-based standard for exchanging authentication assertions between an identity provider and an application.
- SCIM
- A standard protocol for provisioning and deprovisioning users and groups from an identity provider into applications.
- Scope creep
- Requirements growing through small, unreviewed additions without a matching change in time, people or budget.
- Service level objective
- A target for a measured level of service, such as availability or latency; the failure it allows is the error budget.
- Single sign-on
- Signing in once through a central identity provider and using that session across many applications.
- Slowly changing dimension
- A dimension table whose attributes change over time, and the technique used to record the change, such as a new row per version with valid-from and valid-to dates.
- SOC 2
- An auditor’s attestation report on a service organization’s controls against the AICPA trust services criteria.
- Solutions architect
- A customer-facing technical role that designs, advises and often builds proofs of concept; postings place it before the sale, after it, or both.
T
- Token bucket
- A rate-limiting algorithm that refills tokens at a fixed rate and allows bursts up to a capacity.
- Tripwire
- A case-specific failure mode a strong candidate surfaces before it sinks the plan, such as a metric each stakeholder defines differently.
- Trust boundary
- A line where data or calls pass between parts of a system that trust each other differently, and where authentication and validation belong.
V
- Virtual private cloud
- An isolated network inside a cloud provider where the customer controls addressing, routing, egress and private links to other accounts.
W
- Walking skeleton
- The thinnest end-to-end version of a system that performs one small real function across its main components, built first and then extended.
- Window function
- A SQL function computed over rows related to the current row, such as a running total, without collapsing them.