10 Weaviate Software Engineer (New Grad) Interview Questions (2026)

Weaviate's new-grad SWE loop in 2026 is a recruiter screen, a technical phone screen, and three to four virtual onsite rounds. The company builds an open-source vector database — interviews favor candidates who can read open-source code, contribute to public projects, and reason about search-index tradeoffs.

By Alex Chen, Founder, InterviewChamp.AI · Last verified 2026-05-19

Loop overview

New-grad candidates report a 4-6 week timeline in 2026. Phone screen is 60 minutes coding. Onsite is one coding round, one open-source/code-review round (you discuss a public PR or issue), one systems-design round, and one behavioral. The company is fully remote across Europe and the US.

Behavioral (3)

Why Weaviate? What about open-source databases interests you?

Frequently asked

Outline

Talk about a specific Weaviate feature or any open-source database you've used (Postgres, ClickHouse, etc.). If you've contributed to OSS — even doc fixes — name it. Open-source-first companies recruit from contributor pools; signaling familiarity with their public surface matters.

Tell me about a time you contributed to an open-source project.

Frequently asked

Outline

Describe the contribution: what project, what issue, your PR, the review process, what changed in your understanding. If you don't have one — be honest. Talk about contributions you've considered. Don't fabricate; OSS communities are small and reviewers will check.

Tell me about a project where you had to learn a new technology quickly.

Occasionally asked

Outline

STAR. Pick a recent technology or domain you genuinely had to ramp on. Cover how you learned (docs, source code, prototypes, asking), how long, and what stuck. Show metacognition — what's your default learning loop? Engineers who can ramp fast are valued at small companies.

Coding (LeetCode patterns) (3)

Implement a function that given a graph and a starting node, returns nodes in BFS order.

Frequently asked

Outline

Queue + visited set. Pop, emit, push unvisited neighbors. O(V+E). Discuss cycle handling (the visited set), disconnected graphs (loop outer over starts), and the iterator-vs-list output choice. Walk a tiny graph through to anchor.

Given a list of intervals, return the minimum number of conference rooms needed to schedule all of them.

Occasionally asked

Outline

Sort starts and ends separately. Two-pointer: increment room count on a start before the next end; decrement on the next end. Track max. O(n log n). Or: sweep-line with +1 on start, -1 on end, run prefix-max. Walk through a small example.

Implement a function that returns the longest common subsequence of two strings.

Occasionally asked

Outline

DP table of (i, j) = LCS of prefixes of length i and j. Recurrence: match → 1 + dp[i-1][j-1]; mismatch → max(dp[i-1][j], dp[i][j-1]). O(n*m). Reconstruct the subsequence by walking the table from the bottom-right. Discuss space optimization to two rows.

Technical (3)

Given a set of documents and a free-text query, return the top K documents by relevance using BM25 scoring.

Frequently asked

Outline

BM25 = sum over query terms of IDF(term) * (tf * (k1+1)) / (tf + k1 * (1 - b + b * doc_len / avg_doc_len)). Precompute IDF from corpus, doc lengths. Per query: score each doc with query terms, push into min-heap of size K. Discuss inverted-index acceleration vs full scan. Compare to vector search briefly.

Walk me through a code review of this public-issue diff (interviewer screens a GitHub-style PR).

Frequently asked

Outline

Read top to bottom. Comment on: API design, error handling, naming, missing tests, performance, observability. Differentiate must-fix vs nice-to-have. Praise one thing. Pretend the author is an outside contributor — prioritize teaching over correctness alone. Open-source companies grade on this taste.

How would you debug a query that returns the wrong top-K results after an index rebuild?

Occasionally asked

Outline

Check if the index version changed (HNSW parameters drift, embedding dim mismatch). Sample a query and compare exact-brute-force vs index results — divergence size indicates approximation. Check for stale data (last-modified timestamps, missing deletes). Mention canary queries as a regression detector.

System / object-oriented design (1)

Design a system that lets users define schemas for stored objects with field-level types and constraints.

Occasionally asked

Outline

Schema definition language (JSON, proto, or yaml-based). At write time, validate object against schema. Discuss schema evolution: adding fields (compatible), removing fields (need data migration), changing types (need migration with read-time fallback). Mention validation cost on the hot path.

Weaviate interview tips

Open-source contribution history is a strong tiebreaker. Even one merged PR to any project signals you can collaborate at the level the team works.
Schema, indexing, and query-planning thinking come up in design rounds. Brush up on these — not in DB-theory depth, but enough to reason about tradeoffs.
The company writes a lot of Go. You don't need to be fluent for the interview, but if you list it on your resume, expect questions on goroutines, channels, and Go's error idioms.
Remote-first culture means written communication is graded. Be concise in async chat-style answers; the interviewer is implicitly evaluating whether you'd ship clear PR descriptions and issue reports.
Behavioral rounds favor self-directed engineers. Stories about navigating ambiguity, choosing what to work on, and asking the right questions land well.

Frequently asked questions

How long is Weaviate's SWE new-grad interview process in 2026?

Most reports show 4-6 weeks from recruiter outreach to offer. Onsite scheduling is usually quick — within 1-2 weeks of passing the phone screen.

Is Weaviate fully remote for new-grad engineers?

Yes — remote-first with team members across the US and Europe. New grads can typically work from compatible time zones. Confirm with your recruiter.

Does Weaviate ask system design for new-grad SWE?

Yes — one round, focused on storage/search/indexing problems rather than generic web-scale distributed design.

What programming languages does Weaviate use?

Go is the primary backend language. TypeScript and Python are used for client libraries. New-grad interviews are language-agnostic; use whichever you're fastest in.

Do I need ML or vector-search expertise to interview at Weaviate as a new-grad SWE?

Conceptual familiarity helps — know what an embedding is, what cosine similarity does, and the gap between exact and approximate nearest-neighbor search. Deep ML knowledge isn't required for SWE roles.

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