24 Aug 2026 → 10 Jan 2027 · sixteen working weeks · four weeks off

Four-Lane Ledger

NeetCode 150, Designing Data-Intensive Applications 2e, GFE 75, and one behavioural story a week — four lanes running side by side, a section of each per week. Tick a task, leave a note on what actually tripped you up.

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The whole run

Sixteen weeks, four lanes

Algorithms Systems Front end Stories

The ledger

The shelf

Everything this plan leans on

every row takes a note, same as a task

Two questions you asked

How this plan lines up with the Notion “Front-End Preparation” guide

That guide is a reference and answer key, not a second task list. Treating it as more work to do would roughly double the plan for very little new coverage. Treating it as the place you go when a GFE 75 quiz question stumps you costs nothing and saves hours.

Where it already answers GFE 75

Roughly 12 of the 21 GFE quiz questions have written answers in it: hoisting, closures, event bubbling, event delegation, null vs. undefined vs. undeclared, cookie vs. sessionStorage vs. localStorage, script async vs. defer, z-index and stacking context, the box model, box-sizing, positioning, and how a browser matches a CSS selector. In weeks 7 and 8, read its section first and write the answer in your own words in the note field.

Coding exercises that overlap

Its bigfrontend.dev list duplicates GFE 75 on curry, throttle, debounce, flatten, memoize, promisify, event emitter, the async-utils family, and _extend (≈ deep clone / data merging). Do them once, in GFE, where you get tests.

Worth cherry-picking — not in GFE 75

composeFunction.prototype.bindPromise from scratchasync/await from scratchObject.createcustom React renderlevel-by-level DOM traversalDOM tree heightdiff two DOM treesclear all timeoutsobservable

Its prototypal inheritance walkthrough (factory → Object.createnewclass), the this-binding corner cases, and the repaint / reflow section have no GFE 75 equivalent and are still asked. Its accessibility and web-performance sections map onto weeks 12 and 13 here — use them as the reading for those weeks.

What to skip

Its Algorithms track is a Princeton-course-plus-LeetCode-lists plan — a substitute for NeetCode 150, not a supplement. Running both would cost you 200+ extra problems for the same patterns. Pick NeetCode, which you have already started, and ignore that section. Same for its HTML/CSS chapter, which the guide itself labels mostly copy-paste.

How to answer a behavioural question

Every one of the five loops has a dedicated behavioural round, and two of them — Cloudflare’s Orange Cloud and Spotify’s values round — are scored as filters, not formalities. This is the lane with the best return per hour, because almost nobody prepares it.

The shape

STAR, plus an R. Situation in one sentence — just enough to place the listener. Task: what was specifically yours. Action: about sixty per cent of your airtime, and say I, not we — “we” is where interviewers lose the signal. Result: a number. Reflection: what you would do differently. That last beat is what separates an answer that happened from an answer that was rehearsed, and staff-level rubrics probe for it directly.

Two minutes, then stop

Cloudflare caps that round at thirty minutes, which is roughly six stories. A six-minute answer costs you half the round. Rehearse against a timer until the whole arc fits in two minutes, and let the interviewer pull the detail out of you — their follow-up questions are where the good signal is anyway.

Lead with the outcome, then rewind

“We took p95 from 4.2 seconds to 900 milliseconds — here is how that started.” Interviewers write their impression down in the first twenty seconds. Do not spend those twenty seconds on org chart and background.

Name the scope out loud — this is the staff line

An answer that stops at your own team reads as senior, however good the work was. Say who outside your team changed what they were doing because of you. Then say what you deliberately did not do: “we consciously didn’t migrate the legacy path, because…”. Volunteering a non-goal is the single strongest staff signal, and hardly anyone offers one unprompted. Pair it with the rollback plan you had.

Quantify, or failing that, scale

If you genuinely have no metric, give a size instead: “the three teams that consumed it”, “about forty per cent of our traffic”, “a fourteen-person org”. Precision anywhere buys credibility everywhere. Vagueness reads as invention, so keep a fact sheet in each note: dates, headcount, the metric, the real name of the system.

Own the failure stories completely

Do not bring a weakness that is secretly a strength — interviewers have heard it and it costs you trust for the rest of the round. Bring a real one, keep the retelling short, and spend the airtime on what you changed afterwards and what has happened since.

One story answers several questions

A good story can serve three or four prompts with a different emphasis each time. Sixteen of them covers most loops — as long as you know which angle each one can turn. Note the alternate angles at the bottom of each story.

The 2026 addition

Expect to be asked how you used AI on the work: where it helped, where you overrode it, how you checked it. Google now grades that explicitly. Have one honest story where the answer is “it was confidently wrong and here is how I caught it”.

Practicalities

  • Bullet the five beats. Never write it out in full — a memorised paragraph sounds memorised.
  • Say it out loud three times before you call it done. It is a different skill from writing it.
  • Bring your own question to the closing round. That round is scored too.
What five real loops test — Datadog, Cloudflare, Revolut, Spotify, GitHub

These five run genuinely different loops, and the differences are not cosmetic. Of the fifteen-odd rounds below, one is a LeetCode-style algorithm round. Everything else is code you would actually ship, code somebody else wrote, or you explaining a system out loud.

DatadogSenior / Staff FE

Recruiter → online assessment → technical phone screen → onsite of four or five 45–60 min rounds: one or two coding rounds on practical JavaScript and React patterns, one or two front-end system design rounds, behavioural, and a project deep dive.

The staff difference: at Staff and above a presentation replaces one coding round.

→ Week 15 builds that talk. Week 16 delivers it to someone who interrupts.

CloudflareSenior FE / full stack

Five to seven rounds: hiring-manager screen (architectural reasoning plus a résumé deep dive on hard decisions), Orange Cloud behavioural — strictly 30 minutes — a PM interaction round, a dedicated debugging round, system design, and an AI-assisted coding round. Front-end roles add a one-hour React + TypeScript app-coding round where execution speed counts as much as correctness.

→ Week 14 becomes debugging and code review. Week 15 adds the PM round beside the AI-assisted rehearsal. Week 10 drills speed.

RevolutSenior FE

Recruiter → HackerRank (data structures, algorithms and SQL, timed) → 45–60 min live coding → system design → a substantial take-home plus architecture review → bar raiser. Reported as one of the most demanding loops in UK fintech.

The failure mode is specific: most candidates who fail the live round produce working code that is not production quality. A take-home without tests, or half-finished, is an automatic no.

→ Week 10 becomes three 45-minute builds with unit tests plus a cold review of your own code. Weeks 12–13 produce a real take-home artefact. Week 10 adds SQL.

SpotifySenior / Staff

Five to seven stages over two to five weeks: recruiter, technical screen, then a loop of coding, system design, a case study drawn from a real problem the team hit, and a values round. Senior and staff add a 60-minute architecture deep dive through one significant system from your own background.

Two things worth taking seriously: the case study is the round that most often sinks LeetCode-only candidates, and the values round is a filter, not a formality.

→ Week 14 writes up one of your own systems properly. The Stories lane is the values round.

GitHubSenior SWE

Take-home (48–72 hour window, three to five hours of work) → a pairing exercise modelled on daily work, including code review → a system or domain round → behavioural on remote-first collaboration → hiring manager. Around 36 days end to end.

The take-home is scored on code quality, git hygiene and documentation as much as on the solution.

→ Weeks 12–13 build the artefact README-first, with a commit history you would show a reviewer. Week 14 adds reviewing somebody else’s PR.

The five gaps this closed

  • No take-home artefact. Two of the five gate on one, and both judge documentation and commit history. You now build one across weeks 12 and 13 instead of improvising it under a 72-hour clock.
  • No debugging or code-review practice. Cloudflare has a dedicated debugging round; GitHub pairs you on review. Both were entirely absent. Week 14 is now theirs.
  • No deep dive on your own work. Datadog, Spotify and Cloudflare all ask you to walk through a system you built. Week 14 writes it down with a diagram, the trade-offs, the non-goals and the rollback plan — the four things staff-level interviewers listen for.
  • No presentation. At Datadog Staff it literally replaces a coding round. Week 15 builds it.
  • No behavioural preparation at all. All five have a dedicated behavioural round, two of them explicitly weighted as filters. Hence the fourth lane.

Senior versus staff, in one line

A senior answer can be about a system you owned. A staff answer has to name someone outside your team who changed what they were doing because of you — plus the non-goals you chose and the rollback plan you had. That is why every prompt in the Stories lane asks for scope, and why week 16 ends on a cross-team architecture case rather than another algorithm.

Should you pivot the materials for how big tech interviews now run?

Re-weight, don’t pivot. All three sources are still the right ones; what has changed is how much of the loop they cover. The 2026 signal is consistent across sources:

  • Algorithm rounds are still the baseline gate — Google, LinkedIn and Microsoft show the clearest DSA signal — but they are one round, not the loop.
  • Google has added a code-comprehension round: read, debug and optimise an existing codebase, with Gemini available, and your use of it graded — prompting, validating output, catching what the model gets wrong.
  • Front-end loops moved from JS trivia to practical UI tasks: build this component, debug this layout, design this state-management pattern.
  • Meta and Google are piloting AI-assisted rounds and Canva now expects candidates to use AI tools — but a January 2026 Karat survey still found 62% of organisations prohibit AI in technical interviews. Prepare for both rules.
  • The widely-repeated split is roughly 30% algorithms, 70% system design and practical engineering.

What that changes in this plan

  • NeetCode stays, but timeboxed. 45 minutes per problem, then read the solution and write the pattern in the note field. Finishing 150 slowly is worth less than owning 18 patterns.
  • DDIA gets more valuable, not less. It is the deepest lane you have for the part of the loop that grew. That is why every chapter here carries a second task: name the one trade-off you would actually cite out loud.
  • GFE ordering is inverted. Implementation and UI builds come first (weeks 1–6), quiz last (weeks 7–8) — the quiz is the part that decayed most in value.
  • Weeks 10–16 are the new material. Speed rebuilds, React hooks with tests, an accessibility pass, a performance pass, a code-comprehension drill on an unfamiliar repo, one deliberate AI-assisted rehearsal, and full mock loops. That block is the answer to the trend, and it is why the plan does not end when GFE 75 does.

One thing this plan deliberately does not add: a separate LeetCode grind on top of NeetCode 150. The evidence points the other way.

Two resources worth adding, from the Front-End Engineer Blog channel

Evgenii Ray — the author of the Notion guide above, now SWE at Meta in London — spent the past year interviewing across HFT, finance and FAANG and turned the questions into a free two-day Frontend Masters intensive in March 2026: around 60 front-end problems solved live, ending in a small Google Sheets clone, with the problems published as a GitHub repo. He has an earlier Frontend Masters course on front-end system design too. Both sit closer to what these loops now ask than the GFE quiz does.

Two of his choices are worth copying. He solved that entire stream by hand, no AI agents — which is the skill 62% of loops still test. And he is redirecting his own learning at client-side AI engineering and model optimisation, alongside Meta’s Dev AI Infrastructure team. If you want one differentiator beyond this plan, that is the one a staff-level front-end candidate can credibly claim in 2026.