What a profile reveals

One real example profile. The same page reveals more as a company moves from no account to a paid plan, then unlocks. Hidden fields are never sent to the browser, just removed.

  1. No account
  2. Company plan
  3. Unlocked

What anyone sees, signed in or not: the full achievements — the proof — plus skills, mission, domains, timezones, country and employment preferences. Completely anonymous: no name, no salary, no social links, and projects and in-public work show only their skills. Even the profile's public address is an opaque slug, never a name. A free account, talent or company, adds nothing to this.

p99 dropped from ~900ms to ~180ms; timeout rate fell below 0.1% — an 80% reduction sustained at 3x prior peak throughput.

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Proof of work

2026

Cut checkout API p99 latency by 80% under peak load

Under campaign traffic the checkout API degraded badly — p99 hit ~900ms, timeouts spiked, and customers were abandoning carts at the last step. I profiled the hot path instead of guessing, moved read-heavy lookups behind a write-through cache with event-driven invalidation, and added a covering index for the worst query. Each change shipped behind a flag with the old path one toggle away.

p99 dropped from ~900ms to ~180ms; timeout rate fell below 0.1% — an 80% reduction sustained at 3x prior peak throughput.

GoPostgreSQLRedis
2025

Designed an idempotent ledger — 0 double-charges in 12M txns

Retries sometimes double-posted transactions, so finance spent days reconciling and customers stopped trusting their statements. Live data had to migrate with zero downtime. I made every write idempotent behind a client-supplied key and rebuilt the balance model as an append-only ledger that is the single source of truth, with optimistic concurrency so safety did not cost throughput.

Double-charge incidents went to zero — 0 across ~12M transactions over two quarters.

GoPostgreSQLKafka
2024

Cut infra spend 52% by right-sizing a Kafka pipeline

The event pipeline was provisioned for a peak that never arrived — partitions and consumer groups sized off a forecast, burning budget every month with nobody owning the number. I measured real throughput and lag across a full cycle, repartitioned around the actual key distribution, scaled consumers on lag instead of a fixed count, and tuned retention to what teams actually replayed.

Monthly pipeline cost dropped ~52% with p99 consumer lag held under 2s — sustained through the next traffic peak.

KafkaGoKubernetes

I believe the best systems are boring on the surface and ruthless underneath — correct, observable, and quietly fast under load.

Off the clock

Locked
GoRedis
Locked
PostgreSQLTypeScriptGrafana

In public

System DesignCaching
Locked
Webpack
Locked

Practical bits

Timezones
Europe/AfricaAmericas EastAmericas West
Location
Poland
Languages
English, Spanish
Domains
Fintech, Banking
Employment
Full-time · Contract
Annual salary
Available with a company account
Social links
Available after unlocking

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