Merge · Software Engineer
Updated · 2026-10-02

Merge Software Engineer
Interview Guide

THE 60-SECOND BRIEF

As a Software Engineer on the Experience Engineering team at Merge, you will play a critical role in shaping the developer-facing products that power the modern integration ecosystem. Merge is the leading provider of agentic tools and customer-facing integrations, trusted by frontier LLM providers, Fortune 500 organizations, and top-tier B2B SaaS companies. The Experience Engineering team is a full-stack, product-driven group tasked with making highly complex, multi-platform integrations feel seamless, reliable, and intuitive for thousands of developers worldwide. In this role, you will work directly on the core surfaces that define the Merge developer experience, including the customer-facing dashboard, comprehensive documentation, APIs, and SDKs.

This guide is scoped to a Software Engineer candidate at Merge.

Merge candidates report 4 rounds over 3-5 weeks. The stages below are what candidates describe, not a published process.

Backend engineeringFull stack engineeringAPI development

18 min read

Practice 2+ Merge questions

See the practice prompts

As a Software Engineer on the Experience Engineering team at Merge, you will play a critical role in shaping the developer-facing products that power the modern integration ecosystem. Merge is the leading provider of agentic tools and customer-facing integrations, trusted by frontier LLM providers, Fortune 500 organizations, and top-tier B2B SaaS companies. The Experience Engineering team is a full-stack, product-driven group tasked with making highly complex, multi-platform integrations feel seamless, reliable, and intuitive for thousands of developers worldwide. In this role, you will work directly on the core surfaces that define the Merge developer experience, including the customer-facing dashboard, comprehensive documentation, APIs, and SDKs. Your engineering decisions will directly impact how quickly customer engineering teams can deploy integrations, reduce churn, and unblock enterprise sales. Because Merge serves as the central integration layer for its clients, you will tackle unique challenges around data synchronization, high-availability APIs, and complex state management across hundreds of third-party platforms. This position requires a balance of product intuition and deep technical capability. You will not just write clean, maintainable code; you will also actively participate in architectural roadmapping, collaborate with designers and product managers, and interact directly with customers to solve real-world integration bottlenecks.

01

Recruiter Screen

reported

Initial screening call with a recruiter to assess candidate fit and discuss the role.

What to demonstrate

  • Initial screening call with a recruiter to assess candidate fit and discuss the role
  • Depth in Backend engineering

How to prepare

  • Be able to walk your CV end to end in two minutes, and say why this company specifically.
  • Have your salary expectations, notice period and location constraints ready, and ask for the rest of the loop in writing.
Merge Software Engineer candidate reports ↗
02

Technical Screening

reported

Assessment of core coding capabilities through technical questions or exercises.

What to demonstrate

  • Assessment of core coding capabilities through technical questions or exercises
  • Depth in Backend engineering

How to prepare

  • Answer aloud and timed: Solve a classic string manipulation or array-based LeetCode Medium problem, ensuring you walk through your edge cases and optimize for time complexity.
  • Answer aloud and timed: Explain the difference between composition and inheritance, and write a class structure that demonstrates how you would model a reusable integration connector.
Merge Software Engineer candidate reports ↗
03

Virtual Onsite Loop

reported

Multiple deep-dive technical sessions and a dedicated behavioral round conducted virtually.

What to demonstrate

  • Multiple deep-dive technical sessions and a dedicated behavioral round conducted virtually
  • Depth in Backend engineering

How to prepare

  • Answer aloud and timed: What specific web frameworks (such as Django, Rails, or React) have you used extensively, and what are the major architectural trade-offs of those technologies?
  • Answer aloud and timed: Describe a complex database schema you designed in Postgres. How did you handle indexing, scaling, and query optimization as data volume grew?
Merge Software Engineer candidate reports ↗
04

Executive Involvement

reported

Final stages of the interview include participation from executive leadership or founders.

What to demonstrate

  • Final stages of the interview include participation from executive leadership or founders
  • Depth in Backend engineering

How to prepare

  • Answer aloud and timed: What has been the most technically challenging problem you have solved in your career so far, and what did you learn from the outcome?
  • Answer aloud and timed: How do you manage state and maintain high performance when building highly interactive frontend components in a framework like React?
Merge Software Engineer candidate reports ↗

1 candidate reports. Individual accounts describe a particular role and hiring cycle.

Software Engineer

Merge Software Engineer Interview Experience — Data Class Design Then a 3-Level Org Chart Problem, Rejected

Technical ScreenOutcome: rejected

The questions were quite different from the earlier interview reports. The difficulty isn't high, but you need to write code fast. The interview was split into two parts. Part 1: I was first given a set of API return values and asked to design a common data class to store that data. This part took about 20-25 minutes, and they also asked a few simple questions about DB and system design. Part 2:…

Read full experience

PracHub editorial advice for the preparation topics above.

01

Do your homework on the product

Before your first interview, sign up for a demo or read through the Merge API documentation thoroughly. Understand the difference between Merge Unified and Merge Agent Handler. Being able to speak intelligently about their core product offerings will instantly set you apart.

02

Prepare your "Why Merge" story

The behavioral interviews place an exceptionally heavy emphasis on this question. Be ready to explain why you are passionate about integrations, developer tools, or the AI agent ecosystem, and how your background aligns with this mission.

03

Think like a product owner

During system design and coding rounds, do not just focus on the code. Discuss the user experience, how developers will interact with your API endpoints, and how your technical decisions impact the overall product reliability.

Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.

12 technical prompts0 include a worked solution

Implement an algorithm to find the shortest path or relationship chain between two nodes in a network, simulat

medium
Coding & Algorithmic Problem Solving

Implement an algorithm to find the shortest path or relationship chain between two nodes in a network, simulating how Merge maps data across different platforms.

Approach
  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. State the target complexity and say which constraint rules the naive version out.
Follow-up
  • How does this change if the input no longer fits in memory?
  • What is the worst case, and how likely is it on real data?

Solve a classic string manipulation or array-based LeetCode Medium problem, ensuring you walk through your edg

medium
Coding & Algorithmic Problem Solving

Solve a classic string manipulation or array-based LeetCode Medium problem, ensuring you walk through your edge cases and optimize for time complexity.

Approach
  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. State the target complexity and say which constraint rules the naive version out.
Follow-up
  • How does this change if the input no longer fits in memory?
  • What is the worst case, and how likely is it on real data?

Canonicalise a request body into a stable idempotency fingerprint

medium
parsingcanonicalisationhashing

idempotency_key.request_fingerprint is a SHA-256 over the method, path and canonicalised body, and a retry whose fingerprint differs must be rejected with 422 rather than served the stored response. Write the canonicaliser. Bodies are JSON up to 256 KB nested at most 32 levels; clients vary key order, whitespace and unicode escaping, and some send 64-bit ids as JSON numbers. Produce a deterministic byte string such that semantically identical bodies match and any semantic difference does not. State your complexity and name two normalisations you refuse to perform.

Approach
  1. Parse once into a tree, then re-serialise under fixed rules: object keys sorted, array order preserved, one escaping convention, no insignificant whitespace. Parsing is O(n) and sorting keys is O(k log k) per object, so O(n log n) overall with O(depth) stack, and the 32-level cap is enforced during parsing because hostile nesting is how a canonicaliser becomes a stack overflow.
  2. Sort keys by their UTF-8 bytes and say why the obvious implementation is wrong in some runtimes: a default string comparison that orders by UTF-16 code units places surrogate pairs, meaning code points from U+10000 up, below U+E000 to U+FFFF, which is not UTF-8 byte order, so two services written in different languages disagree on the same document.
  3. Do not re-encode numbers through a double. IEEE-754 binary64 represents integers exactly only up to 2^53, so normalising a 19-digit id through a float changes it, and 1 against 1.0 cannot be reconciled without deciding whether they are the same value. Preserve the literal token, and require ids as strings at the API boundary if you want them comparable.
  4. Reject duplicate keys rather than picking one. JSON permits them and parsers disagree, most keeping the last, so any choice you make ties the fingerprint to a parser detail that the code handling the request does not necessarily share.
Follow-up
  • A client sends the same logical request with an extra field your API ignores. Same key, different fingerprint, so you return 422. Is that the right answer?
  • Where does the fingerprint get computed relative to request decompression and the body-size limit?

Built from the rounds and topics Merge candidates report.

Small steps. Visible outcomes.0 / 7 completed
ONE WEEK · YOUR PACE

Prepare, practise & reflect

One practical outcome each day. Spend longer where you need it.

0 / 7 done
01Map the Merge loop
  • Write out the reported sequence: Recruiter Screen, Technical Screening, Virtual Onsite Loop, Executive Involvement.
  • For each round, write one sentence on what it is judging, from the description above, and mark the one you are least ready for.

Deliverable: A one-page map of the 4 reported rounds, with the weakest marked.

02Work Backend engineering
  • Spend the session on Backend engineering, which Merge candidates report being tested on.
  • Write one worked example in Backend engineering and time yourself on it.

Deliverable: One timed worked example in Backend engineering.

03Work Full stack engineering
  • Spend the session on Full stack engineering, which Merge candidates report being tested on.
  • Write one worked example in Full stack engineering and time yourself on it.

Deliverable: One timed worked example in Full stack engineering.

04Work API development
  • Spend the session on API development, which Merge candidates report being tested on.
  • Write one worked example in API development and time yourself on it.

Deliverable: One timed worked example in API development.

05Answer out loud: Coding & Algorithmic Problem Solving
  • Answer aloud, timed: Implement an algorithm to find the shortest path or relationship chain between two nodes in a network, simulating how Merge maps data across different platforms.
  • Answer aloud, timed: Design a parser that can ingest varying third-party API payloads and normalize them into a single, unified data structure.

Deliverable: Spoken answers to 2 reported Coding & Algorithmic Problem Solving question(s), under time.

06Answer out loud: Technical Background & System Alignment
  • Answer aloud, timed: What specific web frameworks (such as Django, Rails, or React) have you used extensively, and what are the major architectural trade-offs of those technologies?
  • Answer aloud, timed: Describe a complex database schema you designed in Postgres. How did you handle indexing, scaling, and query optimization as data volume grew?

Deliverable: Spoken answers to 2 reported Technical Background & System Alignment question(s), under time.

07Answer out loud: Behavioral & Cultural Fit
  • Answer aloud, timed: Why do you want to work at Merge, and what excites you most about the API integration and LLM agent tooling space?
  • Answer aloud, timed: Tell me about a time when you had to deal with significant ambiguity on a project. How did you unblock yourself and deliver the project on time?

Deliverable: Spoken answers to 2 reported Behavioral & Cultural Fit question(s), under time.

Expand any day for tasks and deliverables. Your progress is saved on this device.

Behavioural rounds judge the decision you made and what it cost.

Tell me about a time when you had to deal with significant ambiguity on a project. How did you unblock yoursel

medium
Behavioral & Cultural Fit

Tell me about a time when you had to deal with significant ambiguity on a project. How did you unblock yourself and deliver the project on time?

Approach
  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.
Follow-up
  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

How do you handle constructive feedback from a peer or manager during a code review or architectural discussio

medium
Behavioral & Cultural Fit

How do you handle constructive feedback from a peer or manager during a code review or architectural discussion?

Approach
  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.
Follow-up
  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Reverse your own decision and price the reversal

medium
reversibilitymeasurementmigrations

Describe a technical decision you made and later reversed. Pick one that cost something: a service you split and merged back, a cache you added and removed, an index you created that pushed the planner onto a worse plan, a projection you rebuilt from scratch. State what you believed when you decided, the measurement that changed your mind, how long the wrong version ran in production, and what the reversal cost in migrations, dual writes, and a deprecation window for callers you did not own.

Approach
  1. State the original rationale without irony, in the version you would still defend given what was known then. If it is not defensible, the story is about carelessness rather than judgement, and a different example serves you better.
  2. Give the measurement that moved with a before and after: the p99 that did not improve, the cache hit rate that sat at 40%, the plan that flipped to a sequential scan once the table passed a size you can name.
  3. Cost the reversal in steps, not adjectives: expand-and-contract deploys, the dual-write window, the callers who had to be notified, the rows already written in the wrong shape that had to be backfilled or abandoned.
  4. Distinguish reversal from rewrite by naming what you kept. Most good reversals preserve the schema or the interface and undo one decision inside it, which is also why they were affordable.
Follow-up
  • What in that decision was irreversible, and did you know it was irreversible when you made it?
  • How did you tell the people who had already built on top of the original decision?
  • 01

    Tell me about a time when you had to deal with significant ambiguity on a project. How did you unblock yourself and deliver the project on time?

  • 02

    How do you handle constructive feedback from a peer or manager during a code review or architectural discussion?

  • 03

    Describe a technical decision you made and later reversed. Pick one that cost something: a service you split and merged back, a cache you added and removed, an index you created that pushed the planner onto a worse plan, a projection you rebuilt from scratch. State what you believed when you decided, the measurement that changed your mind, how long the wrong version ran in production, and what the reversal cost in migrations, dual writes, and a deprecation window for callers you did not own.

PracHub preparation framework ↗
How technical is the interview process compared to other startups?

The process is highly rigorous and practical. It tests both your theoretical computer science fundamentals through LeetCode Medium-style coding questions and your practical engineering skills through hands-on system design or sandbox exercises.

Merge Software Engineer candidate reports ↗
What is the company culture like at Merge?

The culture is fast-paced, collaborative, and highly transparent. The team is composed of passionate, friendly, and driven individuals who care deeply about product quality. The flat hierarchy means engineers have direct access to leadership and significant input on product decisions.

Merge Software Engineer candidate reports ↗
How long does the entire interview process typically take?

Merge is known for its speed. The entire pipeline, from the initial recruiter screen to the final offer decision, can often be completed in two to three weeks, depending on candidate availability.

Merge Software Engineer candidate reports ↗
Is there a hybrid or in-office policy for this role?

Yes, for roles based in New York, NY, Merge operates on an in-office/hybrid model. The office environment is highly collaborative, featuring perks like daily snacks, free dinners for team members working past 7:00 PM, and regular team offsites.

Merge Software Engineer candidate reports ↗
What topics does Merge test in interviews?

Merge interviews most often cover Stakeholder Communication, Stakeholder Management, Expectation Management, Professionalism, and Process Standardization. The exact emphasis depends on the specific role you apply for.

Merge Software Engineer candidate reports ↗
Sources & methodology 3 sources ↗

No official company page is cited. Rounds and questions come from candidate reports and PracHub editorial material; each source shows the date it was read.