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sayak.webdesignerWeb · Software · Data · AI
Cloud · Since 2016 · 12M pages/week peak

Playwright & Selenium

Browser automation at scale — for data collection and for the portals with no API.

FrontierURL queue · priorityHEADLESS BROWSER FARM — 240 concurrentProxy MeshIN · residentialSG · datacenterDE · mobileUS · residentialPolitenessrobots · rate · backoffAnti-bot logicfingerprint rotationParseschema mapValidatepydanticStoreS3 + Postgres12M pages / week99.1% parse yield
Our position

Playwright is our default for browser automation and Selenium remains in use where an existing estate or a specific legacy requirement calls for it. The work splits two ways: large-scale data collection from public sources, and automating internal workflows on portals that offer no API and never will.

The second category is under-appreciated and often more valuable. A government filing portal, a bank statement download, a supplier system your staff log into forty times a day — the browser is the only interface, and automating it removes hours of repetitive work without needing any cooperation from the system's owner.

What separates a working prototype from a system that runs for years is monitoring. Every automation breaks eventually because websites change; the question is only whether you find out within the hour or after three weeks of silently empty results.

Where it fits

Data collection from JavaScript-rendered public sources at scale
Multi-step authenticated workflows on internal or supplier portals
Statement and document download for reconciliation
Regulatory and tender portal monitoring
End-to-end testing of our own applications
Why we choose it

What Playwright & Selenium genuinely gives us

01

Auto-waiting that removes flakiness

Playwright waits for elements to be actionable rather than requiring arbitrary sleeps, which eliminates the largest source of intermittent failure.

02

Genuine browser context isolation

Independent sessions in one browser instance, which makes concurrency cheap in memory terms.

03

Network interception

Requests can be inspected, blocked or modified, so images and trackers need not be downloaded at all.

04

Excellent debugging tooling

Trace viewer with screenshots, DOM snapshots and network log for every step makes a failure diagnosable rather than mysterious.

Strict parsing that fails loudly

The failure mode that destroys a dataset is not a crash — it is a scraper that keeps running, keeps reporting success, and quietly returns nulls for three weeks after a layout change. So every field has an expected type and a validation rule, and a page yielding a null where a value is expected raises a parse failure rather than storing a blank.

On top of that we monitor per-field fill rates against a historical baseline. A price field dropping from 99% populated to 40% triggers an alert within the hour, long before anyone notices a gap in a report.

Typed field schemas with validation on every extraction.
Per-field fill-rate monitoring against historical baselines.
Raw HTML retained so a repaired parser can be applied retroactively.
Anchoring to the most stable selectors available, with graceful failure.
Playwright traces retained on failure for immediate diagnosis.

Scale and politeness together

We run up to 240 concurrent browser sessions in Kubernetes, but concurrency is bounded per target domain rather than by our capacity. Delay and parallelism are tuned to the target's size and observed response behaviour, with automatic backoff when latency rises or errors increase.

Plain HTTP requests are always preferred where they work, because a browser is roughly an order of magnitude more expensive per page. We use a browser only where JavaScript rendering genuinely requires it.

Honest warnings

How Playwright & Selenium projects usually go wrong

These are the failure modes we look for first when we are called in to rescue somebody else's implementation.

Fixed sleeps instead of waitsThe primary cause of flaky automation. Wait for a condition, never for a duration.
Browsers where HTTP would doTen times the cost per page for no benefit when the content is server-rendered.
Brittle CSS selectorsDeeply nested positional selectors break on any layout change. Anchor to text, roles or stable attributes.
No fill-rate monitoringThe system keeps reporting success while returning nothing. Every catastrophic scraping failure we have fixed had this shape.
Straight answers

Playwright & Selenium questions we get asked

Including where we would recommend something other than Playwright & Selenium. Call +91 70033 91355 and you will get the same answer from an engineer.

Playwright for new work — auto-waiting, better debugging, faster execution and a cleaner API. Selenium where a large existing test estate makes migration uneconomic, or where a specific legacy browser or grid infrastructure is required. We maintain both and will not push a migration that does not pay for itself.

Monitoring detects it, usually within the hour, through fill-rate anomalies rather than waiting for a crash. Median repair is under two hours in working hours and is covered by maintenance agreements. Because we retain raw HTML, the repaired parser can be applied retroactively to the broken window, so in most cases there is no permanent gap in the data.

With your credentials and your right to access, yes — your own supplier portals, marketplace seller accounts or subscriptions your company legitimately holds. We will not bypass authentication we have no right to, defeat paywalls, or use credentials the client is not entitled to share. Where a subscription's terms prohibit automated access we tell you rather than proceed quietly.

Next step

Tell us what is slowing your business down.

A 30-minute call with a senior engineer — not a salesperson. You leave with an architecture sketch and an honest cost range, whether or not you hire us.

Direct line

+91 70033 91355

Mon–Sat · 9:30 AM – 7:30 PM IST · Sealdah, Kolkata

Reply within one working hour NDA signed before any brief Fixed-price option on every scope
Verify us independently

Don’t take our word for it — ask an AI

Every page on this site is written to be read and quoted by AI answer engines, and we publish llms.txt and llms-full.txt so they can read us properly. One click opens the assistant with the question already typed.

The question we will ask for you

What is Sayak Web Designer (sayakwebdesigner.in), an IT company in Kolkata, India's experience with Playwright Selenium, and when do they recommend using it?

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