Accelya Group · Software Engineer
Updated · 2026-09-24

Accelya Group Software Engineer
Interview Questions & Guide 2026

THE 60-SECOND BRIEF

As a Software Engineer at Accelya Group, you are at the heart of the company’s mission to transform the airline industry through innovative financial and commercial technology. You will be responsible for building, maintaining, and scaling high-performance software solutions that handle complex data processing, financial clearing, and settlement services for global aviation partners. This role is not just about writing code; it is about engineering robust, reliable systems that support critical infrastructure for major airlines worldwide.

For a design discussion, a catalogue of architectures is worth less than the ability to turn a vague requirement into a data model and an API contract. A box diagram with no schema under it collapses at the first follow-up question.

Accelya Group candidates report 4 rounds · ≈ 3-5 weeks. The stages below are what candidates describe, not a published process.

Make every write idempotent under client retriesScope every query and cache key by tenantEvolve APIs without breaking pinned SDK clients

33 min read

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See the practice prompts

13Practice promptsAcross five skill areas
3With worked solutionsIncluded in the practice prompts

As a Software Engineer at Accelya Group, you are at the heart of the company’s mission to transform the airline industry through innovative financial and commercial technology. You will be responsible for building, maintaining, and scaling high-performance software solutions that handle complex data processing, financial clearing, and settlement services for global aviation partners. This role is not just about writing code; it is about engineering robust, reliable systems that support critical infrastructure for major airlines worldwide.

The work environment at Accelya Group is defined by scale and technical rigor. You will contribute to products that manage vast amounts of data, requiring a strong grasp of both core engineering principles and domain-specific challenges. Whether you are working on cloud-based platform engineering or core software development, you will collaborate with cross-functional teams to solve real-world problems. Success in this role requires a blend of technical depth, logical problem-solving, and a commitment to delivering high-quality, secure code in a fast-paced environment.

01

Aptitude Assessment

reported

The same problem is scored by two different mechanisms depending on the format, and preparing for one does not cover the other. With a person watching, partial progress is visible and a hint is a correction you can absorb; silence is the expensive failure, because nobody can read a half-written function. With an automated grader there is no partial credit for what you were about to do, nobody to ask, and the worked examples in the prompt are the entire specification. Read them as a contract, down to whether an empty result should be an empty list or no output at all.

What to demonstrate

  • In a live session, whether your commentary tracks what your hands are doing, and whether a hint redirects you or gets defended against
  • In an automated one, whether you cover the cases the examples do not show, since the hidden cases are where the score moves
  • Whether you manage the clock on purpose: abandoning an approach that is not converging while there is still time to write something simpler that finishes

How to prepare

  • Have someone hand you a problem and feed you one deliberately wrong hint. Practise testing it against a concrete case instead of accepting or rejecting it on authority.
  • Do one timed run a week in a plain browser editor with autocomplete, linting and your own snippets switched off, which is closer to what these environments give you
  • For the automated format, write the harness before the solution: a main that feeds the worked examples plus an empty and a single-element case and prints expected against actual, so a wrong submission is caught by you first
PracHub interview research ↗
02

Technical Evaluations

reported

Most of the time lost in this format is not lost to thinking. It goes to a standard-library call you half-remember, an off-by-one in a loop bound, and a debugging loop that mutates code at random until something passes. When output is wrong, stop re-reading the whole function: take the smallest input that reproduces it and walk the state through by hand, printing intermediates if the environment allows. Guessing at a fix without a failing case you understand is how a five-minute bug becomes twenty, and the clock does not pause while you do it.

What to demonstrate

  • Whether you reach the right structure without a detour, and can write it from memory rather than only recall that one exists
  • Whether overflow is considered where the language has fixed-width integers, since a signed 32-bit value stops at 2,147,483,647 and then wraps in Java, is undefined behaviour in C++, and does not arise in Python, whose integers grow instead
  • Whether recursion depth is treated as a constraint on large inputs, given that CPython's default limit is 1000 frames and a deep recursion can exhaust the stack in any language where an iterative version would not
  • Whether a failing case is isolated and explained before any edit is made to the code

How to prepare

  • From an empty file and with no references open, implement the pieces you lean on most: a heap push and pop, an iterative DFS with an explicit stack, and a binary search whose midpoint is written lo + (hi - lo) / 2, which avoids the overflow that (lo + hi) / 2 can hit in a fixed-width integer type
  • Time yourself on the ten library calls you look up most, such as sorting with a custom comparator, splitting and joining strings, and finding the next key at or above a value in an ordered map, until the lookup is gone
  • Take a solution you know is broken and, before touching it, write one sentence naming the input, the expected value and the actual value. Repeat until you do it without deciding to.
PracHub interview research ↗
03

Managerial Discussion

reported

You cannot drill a format you do not know, so put the preparation into material that travels. Three pieces of your own work, each rehearsed until you can take a follow-up you did not anticipate, will carry a conversation or a code walkthrough equally well. Specificity is what separates that from filler. A number needs its definition before it means anything: a p99 is over some window and measured at some hop, and a server-side figure excludes the queueing and network time a client would see. The number you cannot qualify is the one to leave out.

What to demonstrate

  • Whether your examples carry detail only someone who did the work would hold, such as what the binding constraint actually was, which alternative you rejected and why it was worse, and what you measured on each side of the change
  • Whether a number survives one follow-up, meaning you can say what it was measured over and whether it moved because of your change or merely alongside it
  • Whether a failure is described with the specific change that followed it, rather than a lesson stated in general terms
  • Whether your part in a team effort is stated accurately, including what other people did

How to prepare

  • Write a page on each of three projects covering the constraint, the option you rejected, the measurement before and after, and what went wrong. Cut any line you cannot take a follow-up on, since you are writing the parts you will be pressed on rather than a summary.
  • Recover the real figures while you still have access: request volume, data size, latency with its percentile and window, team size, timeline. Note where each came from, whether a dashboard, a design document or memory, and mark the estimates so you can say which they are out loud.
  • Take your weakest project story to someone who works in a different area and have them ask why four times in succession. The point where you run out of answer is the part to go and re-read before the round.
PracHub interview research ↗
04

HR Discussion

reported

When a round has no standard shape, it is often there because something is still open: an area no earlier conversation reached, a round where the signal came out mixed, or a decision someone is not ready to make alone. Work out which by going back over what each earlier round actually covered rather than how it felt, and arrive able to give evidence on that point without being asked twice. Weak answers replay the loop's earlier material at the same depth. Strong ones go a level deeper and stay consistent with what you already said.

What to demonstrate

  • Whether your account of a project matches the one you gave earlier in the loop, since what you said before may be available to whoever runs this round
  • Whether you can go a level deeper on something already covered, reaching the decision and its alternatives rather than repeating the summary
  • Whether you state your own uncertainty accurately, including parts of a system you did not build and decisions you inherited, instead of claiming even ownership across all of it
  • Whether you can answer a question you handled poorly earlier by naming what you missed, rather than delivering a polished second version as if the first had not happened

How to prepare

  • Reconstruct the loop on one page: for each round, the questions you were asked and the answer you actually gave, not the better one you thought of afterwards. The gaps on that page are your best available guess at why this round exists.
  • Take the two claims you made earlier that carry the most weight and assemble the backing for each: the measurement, the date, what broke, the decision you would make differently now.
  • Write down the three facts about your work that must not drift between tellings, such as team size, timeline and your own role, and check your stories against that list rather than trusting recall under pressure
PracHub interview research ↗

PracHub editorial advice for the preparation topics above.

01

Holding money in a floating-point type, or rounding it more than once

Binary floating point cannot represent 0.01 or 0.1 exactly, so sums drift and two code paths that should agree disagree by cents nobody can trace back. The fix is integer minor units or an exact decimal type end to end, with sub-cent rates expressed as scaled integers such as micro-units, because a per-request price genuinely is smaller than a cent. The second half of the trap is rounding position: rounding each line and then summing gives a different total from summing and rounding once, and half-up and half-even diverge systematically across many lines, so rounding must happen at one named place and every downstream reader must carry the rounded value rather than recompute it from quantity and rate.

02

Serialising a tenant's writes through select ... for update on a single counter row

It is the first change that makes a counter correct, and it caps that tenant's write throughput at roughly one divided by the lock hold time. A transaction that takes the lock, makes a network call and then commits holds it for the entire round trip: at 2 ms that is about 500 writes per second for the whole tenant, and the largest tenants are exactly the ones that exceed it. The damage then spreads, because every waiter holds a database connection while it queues, so one hot tenant drains the shared pool and the symptom presents as a site-wide latency incident rather than as a lock problem. The repairs are to shrink the critical section to a single statement, to shard the counter into per-(tenant, hour) or per-(tenant, bucket) rows and sum on read, or to batch in memory and flush periodically while accepting the bounded loss that batching implies.

03

A queue or buffer with no bound

Every producer-consumer boundary needs a capacity and a policy for reaching it: block the producer, shed load, or drop the oldest entry. Unbounded buffering converts a temporary slowdown into memory exhaustion and hides the backpressure signal that would have revealed the consumer was falling behind.

04

Trusting input because it came from your own front end

Anything crossing a trust boundary is hostile: parameterise queries instead of building SQL by concatenation, validate against an allow-list rather than a deny-list, and bound the size of anything you allocate from a request. Raising this unprompted in an API or design question is a cheap and unusually strong signal.

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

10 technical prompts3 include a worked solution

Detect and remove duplicates from a linked list.

medium
data structures and algorithms

Detect and remove duplicates from a linked list.

Approach
  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. State the target complexity and say which constraint rules the naive version out.
  3. Name the brute-force solution and its complexity before improving on it.
Follow-up
  • How does this change if the input no longer fits in memory?
  • Which test case would catch an off-by-one here?

How do you find non-repeating characters in a string using a HashMap?

medium
data structures and algorithms

How do you find non-repeating characters in a string using a HashMap?

Approach
  1. Choose the data structure from the access pattern, not from familiarity.
  2. Name the brute-force solution and its complexity before improving on it.
  3. 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?
  • Which test case would catch an off-by-one here?

Check if a string or number is a palindrome.

medium
data structures and algorithms

Check if a string or number is a palindrome.

Approach
  1. Name the brute-force solution and its complexity before improving on it.
  2. State the target complexity and say which constraint rules the naive version out.
  3. Restate the input: its shape, its size, and what is guaranteed about it.
Follow-up
  • How does this change if the input no longer fits in memory?
  • Which test case would catch an off-by-one here?

Hold a tenant to a trailing sixty-second request limit

mediumWorked solution
sliding-windowtwo-pointerrate-limitingtenant-skew

The gateway must hold each tenant to R requests in any trailing 60 seconds, in aggregate across three regions and every pod, within a budget of under 10 ms added p99. Peak is 30,000 requests/second across 200,000 active tenants, and traffic is heavily skewed toward a handful of them. Give an exact single-process algorithm with its amortised per-request cost and its memory per tenant, then a bounded-memory approximation and the worst-case overshoot it actually admits. Say what the distributed version does when the counter store is unreachable.

Approach
  1. Exact, single process: a per-tenant deque of request timestamps. On arrival, pop from the front while front <= now - 60s, then admit if the remaining length is below R and push. Each timestamp is pushed once and popped once, so the cost is O(1) amortised. The O(R) version is the one that re-filters the whole deque on every request.
  2. Quote the memory. R = 1,000 across 200,000 active tenants is up to 2 x 10^8 timestamps at 8 bytes, about 1.6 GB, and that is the worst case rather than the mean, because the long tail of small tenants holds almost nothing. Skew helps you here and hurts you in the sharding decision.
  3. Bounded alternative, with its real bound stated: a fixed 60-second counter is O(1) memory but admits close to 2R across a 60-second span straddling a boundary. The weighted two-bucket estimate, prev * (60 - elapsed)/60 + cur, is better on smooth traffic but assumes the previous window's arrivals were uniform; an adversary packing them at the end of that window is undercounted and can still approach 2R. Say that rather than calling it exact.
  4. Token bucket is the usual gateway answer and a different contract: O(1) state per tenant (tokens, last_refill), a sustained rate, and a deliberate burst allowance equal to the bucket size. Choose it when a burst is acceptable and the log when the limit is contractual.
  5. Distributed: the limit is per tenant in aggregate, so a local bucket of R/N per pod is wrong in both directions under skew. A tenant landing on one pod is throttled at R/N, and a tenant spread evenly across pods exceeds R. The shared check must be a single atomic round trip, one script or one increment-and-compare, never read-then-write, and it must fit inside the 10 ms p99 budget.
  6. Decide the unavailable case in advance and write it down. Failing open keeps the product up and lets a tenant exceed its limit for the duration; failing closed converts a counter-store outage into a full outage. Most gateways fail open on rate limits and closed on authorisation, and those are two separate decisions made separately.
Worked solution 25 min
  1. Implement the deque version and instrument the per-request pop count, then confirm total pops equal total pushes over a run.
  2. Generate a burst that places R requests in the last 100 ms of one minute and R more in the first 100 ms of the next.
  3. Run that burst through the exact deque, a fixed 60-second counter, and the weighted two-bucket estimate, recording admissions in the trailing 60 seconds at every instant.
  4. Size the memory as R x active tenants x 8 bytes at R = 1,000 and 200,000 tenants, and compare it against what a token bucket would need.
EXPECTED RESULTThe exact deque never admits more than R in any trailing 60-second window. The fixed counter admits close to 2R across the boundary. The weighted estimate lands between the two on this burst and approaches 2R once the previous window's requests are packed at its end.
Follow-up
  • One tenant sends 40% of all traffic. What does that do to a single counter key, and what do you shard on instead?
  • Quotas rather than rate limits: the check is select used; if used < limit then insert. Name the isolation level that still permits the overshoot, and the two fixes.
  • How do you return an accurate Retry-After from the exact algorithm without a second scan?

Four days sample coding, design, fundamentals and the practical rounds at deliberately shallow depth, which is enough to surface the topics you did not know were in scope. That map, rather than a guess made on day one, decides where the last three days go.

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
01Coding, one pass at shallow depth
  • Solve one problem from each of six families, an array with two pointers, hash counting, binary search, a tree traversal, a graph traversal and one dynamic program, under a hard twenty-minute cap with no extensions, marking each finished, late, or stalled.
  • For every stall, write the exact move you could not make rather than the subject, so the note reads could not turn the recurrence into a loop rather than bad at dynamic programming.
  • Fix nothing today. The value of the pass is the unfixed record.

Deliverable: Six timed attempts marked finished, late or stalled, each stall carrying a named blocking move.

Practice prompt ↗Practice prompt ↗Worked solution ↗
02Design, one pass at shallow depth
  • Spend twenty minutes each on three different shapes, a read-heavy feed, a write-heavy ingest path, and something needing a transaction across two entities, stopping each at requirements, interface and data model.
  • After each, write the first question you could not answer, which is usually a number you could not estimate or a failure mode you had no vocabulary for.
  • Mark which of the three you would be most relieved not to be asked, and treat that as data rather than as a preference.

Deliverable: Three shallow designs, each with the first unanswerable question written at the bottom.

Practice prompt ↗Practice prompt ↗
03Fundamentals and the practical rounds
  • Answer eight short questions in writing at four minutes each, covering the material that fills the gaps between the big rounds: what happens between a URL and a rendered page, what an index costs on write, when a process is preferable to a thread, and what conditions a deadlock requires.
  • Do one thirty-minute practical task of the kind a take-home compresses: read an unfamiliar two-hundred-line file and write what it does, what you would change, and the one thing you remain unsure of.
  • Score every answer fluent, correct but slow, or absent, and keep the absent ones visible.

Deliverable: Eight scored short answers and one written reading of unfamiliar code.

Practice prompt ↗Practice prompt ↗
04The rounds that are about you, and the map
  • Deliver three behavioural answers aloud against a timer, a conflict, a failure you owned, and a decision made without enough information, marking any that ran past three minutes or contained no number.
  • Assemble the map: every marked item from days one to three on a single page, sorted by how likely it is to appear in your loop rather than by how uncomfortable it felt.
  • Choose exactly two areas for the remaining three days and write down what you are deliberately abandoning.

Deliverable: A one-page scored map of the whole surface area with two areas chosen and the rest explicitly abandoned.

Practice prompt ↗Practice prompt ↗Worked solution ↗
05First chosen area, to the depth you skipped
  • Work the higher-ranked area in four focused blocks, choosing items one level above where you stalled rather than repeating what already works.
  • After each block write the rule you extracted in one sentence with its precondition attached, since a rule carrying no precondition is exactly what fails under a variation.
  • Re-attempt the day-one or day-two item that exposed this area and compare against the original timing.

Deliverable: Four worked blocks, a timed re-attempt against the original, and three one-sentence rules with preconditions.

Practice prompt ↗Practice prompt ↗
06Second chosen area, where the gap is coverage rather than speed
  • Treat the second area differently from the first. Day five drilled something you could already half-do; this one is usually a topic you had simply never met, so build one worked reference example end to end and keep it, rather than attempting six problems badly.
  • Write down the vocabulary you were missing on day two or three, five terms at most, each with the one sentence that makes it usable in an answer rather than the textbook definition.
  • Redo the shallow attempt that exposed this area and note whether you now fail later in the problem, because moving the failure point is the realistic gain from a single day and is worth more than a score that did not change.

Deliverable: One worked reference example for the newly covered area, a five-term vocabulary list, and a note on where the failure point moved.

Practice prompt ↗Practice prompt ↗
07Reassemble the loop
  • Sit two rounds back to back with no gap, ordering them so the area you chose second comes last, because the map was built from rested, isolated attempts and the loop will reach your weaker area when you are already spent.
  • Write where the second round suffered from the first, which is normally the point at which structure collapses into narration.
  • Reduce the week to one page holding only the rules you can state without reading them.

Deliverable: Mock notes on cross-round carryover plus a one-page card of rules you can recite from memory.

Practice prompt ↗Worked solution ↗

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

Bring the two or three numbers the story rests on and know how they were collected. A p99 whose timer starts inside your handler excludes the time a request spent queued, so it can sit flat while users wait longer. Give the window, the percentile and what the measurement left out, or drop the number.

How do you ensure your code is secure and memory-efficient?

medium
behavioural and engineering judgement

How do you ensure your code is secure and memory-efficient?

Approach
  1. Name the disagreement and how you resolved it with evidence.
  2. Give the blast radius: what could have broken, and what you measured.
  3. State the situation in two sentences and spend the rest on the reasoning.
Follow-up
  • What would you do differently if you ran that again?
  • What did you decide not to do, and why?

Describe a challenging technical problem you faced and the specific st…

medium
behavioural and engineering judgement

Describe a challenging technical problem you faced and the specific steps you took to solve it.

Approach
  1. Give the blast radius: what could have broken, and what you measured.
  2. Close with what you would do differently, concretely.
  3. State the situation in two sentences and spend the rest on the reasoning.
Follow-up
  • What did you decide not to do, and why?
  • What would you do differently if you ran that again?

Tell us about a project on your resume—what was your specific contribu…

medium
behavioural and engineering judgement

Tell us about a project on your resume—what was your specific contribution?

Approach
  1. Name the disagreement and how you resolved it with evidence.
  2. Close with what you would do differently, concretely.
  3. Pick a story where you made the decision, not one where you watched it.
Follow-up
  • What did you decide not to do, and why?
  • How did you know your change caused the improvement?
  • 01

    How do you ensure your code is secure and memory-efficient?

  • 02

    Describe a challenging technical problem you faced and the specific steps you took to solve it.

  • 03

    Tell us about a project on your resume—what was your specific contribution?

PracHub interview preparation framework ↗
Is this an official Accelya Group interview guide?

No. It is PracHub's own research and practice material for the Software Engineer role at Accelya Group. Rounds and questions reflect what candidates have reported, not a process Accelya Group has published, and they change over time. Confirm the current format and scope with your recruiter.

PracHub interview research ↗
How long should I prepare for the interview?

Given the technical nature of the rounds, plan for at least 2–3 weeks of focused preparation. Prioritize solving DSA problems on platforms like HackerRank and refreshing your core language concepts.

PracHub interview research ↗
What is the most common reason candidates are rejected?

Lack of clarity in explaining logical reasoning or inability to write functional code during the technical round. Remember that the interviewer is looking for your thought process, not just the correct answer.

PracHub interview research ↗
Is the culture at Accelya Group collaborative?

Yes. Candidates frequently report that interviewers are supportive and helpful, providing guidance during the technical rounds. They prioritize a culture where engineers can communicate openly.

PracHub interview research ↗
What is the typical timeline from the first screen to an offer?

While it can vary, the process is generally paced well. However, be prepared for potential delays and maintain professional communication with your recruiter throughout the process.

PracHub interview research ↗
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.