Free tools Windows power users keep installed
One-click scans. No signup required.
An effective web-scraper input schema is a clear, validated contract between the person or system starting a crawl and the scraper that runs it. Define only caller-controlled values, give routine behavior sensible defaults, validate real constraints before work starts, and make the generated form understandable. In Apify, an Actor input schema also drives validation, the Console form, API documentation, and integration examples; other frameworks use different syntax and may not generate a form at all.
Start with the scraper’s public contract
Before writing schema syntax, list what a caller must be able to change without editing scraper code. Typical inputs include a set of start URLs, a crawl limit, a site-specific search term, pagination settings, authentication data, or a choice of output mode. These are design examples, not a universal field list.
Keep implementation details private. A caller usually needs to say “crawl these URLs” and perhaps “stop after 500 pages”; they should not have to supply an internal queue name, CSS selector that never changes, or a browser flag that the scraper can choose automatically.
Separate required values, defaults and prefills
- Required: information without which a meaningful run cannot proceed. A start URL is required when the scraper has no other target source.
- Default: a behavior the scraper needs but most callers should not configure. For example, a conservative page limit can be applied whenever the caller omits
maxPages. In Apify, defaults are supplied for API, CLI, scheduler and Console starts. - Prefill: a UI example. Apify documents prefills as a way to show a test value when a field has no reasonable default; a prefill is UI-only and should not be mistaken for a value sent by API callers.
This distinction prevents a dangerous assumption: an example URL displayed in a form does not mean an automated launch will receive that URL.
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
- Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
Model a small, typed root object
Use one root object and give every public property one accepted type. Apify’s documented input types are string, array, object, boolean and integer. Its schema resembles JSON Schema but adds extensions and differences, so validate with the platform’s validator rather than assuming every generic JSON Schema tool behaves identically.
The following conceptual schema shows a useful starting point for a hosted scraper. Field names are examples; adapt them to the actual crawler.
{
"schemaVersion": 1,
"title": "Catalog crawler input",
"type": "object",
"properties": {
"startUrls": {
"title": "Start URLs",
"type": "array",
"description": "Pages where crawling begins.",
"editor": "requestListSources",
"minItems": 1,
"maxItems": 100
},
"maxPages": {
"title": "Maximum pages",
"type": "integer",
"description": "Upper bound for pages fetched in this run.",
"default": 500,
"minimum": 1,
"maximum": 100000
},
"query": {
"title": "Catalog query",
"type": "string",
"description": "Optional site search term.",
"maxLength": 200
},
"followNext": {
"title": "Follow next-page links",
"type": "boolean",
"default": true
}
},
"required": ["startUrls"],
"additionalProperties": false
}The exact editor names and available keywords depend on the framework. The important design is visible to any reader: one or more URLs are needed, the page count is bounded, the query is optional, and pagination has an explicit default.
Use constraints that express reality
A type check alone will accept many values your crawler cannot use. Add constraints for the actual requirement:
- Strings: minimum and maximum length, a pattern for a known identifier format, or an enumeration for a genuinely closed set.
- Integers: lower and upper bounds that protect the target site and your run budget.
- Arrays: minimum and maximum item counts, plus item schemas so every entry has the expected shape.
- Objects: nested properties, required nested keys and, where appropriate, their own
additionalPropertiespolicy.
Write validation messages in user language: “Enter at least one start URL” is more useful than “minItems violated.” Rejecting an impossible input before the Actor starts is cheaper and easier to explain than failing after requests have been made.
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
Choose a form that matches each value
Schema-driven interfaces are only helpful when the control matches the data. In Apify’s documented input UI capabilities, use a URL-list editor for start URLs, a select control for a truly closed set of options, and a code editor when the caller must enter code-valued text. Put advanced settings in a separate section when the platform supports grouping, and use descriptions for practical examples, units and side effects.
Do not turn an open-ended value into a select merely to make the form look tidy. If a site accepts arbitrary CSS selectors, a text or code editor is more honest than a list containing a few examples. Conversely, if the scraper supports only html and json output, an enumeration prevents spelling variants from reaching execution.
Decide how strict the contract should be
Unknown fields are a compatibility decision, not a purely technical one. Apify documents permissive additionalProperties behavior by default at the root and nested-object levels. Set it to false when undeclared fields should fail early; this catches typos such as maxPage instead of maxPages. Before tightening a published interface, check existing API clients, schedules and saved inputs, because callers that send extra metadata may break.
A practical rollout is to document accepted fields first, observe callers, then enforce strictness in a versioned change. If compatibility matters more than typo detection, keep the object permissive but ignore unknown values deliberately and document that behavior.
Discover inputs for JavaScript-heavy targets
A schema cannot compensate for choosing the wrong data source. When a page fills its table after JavaScript runs, inspect the browser’s network activity and identify the request that returns the records. Scrapy’s workflow documentation (version 2.1.0) recommends reproducing that request, including its HTTP method and URL and, when needed, its body, headers and form parameters.
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
Prefer a structured request when it works
If an XHR or fetch response already contains JSON, expose only the values that change that request: search text, page number, filters, or date range. This usually avoids a full browser and makes retries, rate limiting and validation simpler. Do not add a generic “render JavaScript” switch to every schema before checking whether a direct data request is available.
Use rendering when the artifact requires it
A headless browser remains appropriate when the target requires client-side execution, the data is assembled in the browser, or the requested output is a browser-visible artifact such as a screenshot. Rendering adds startup time and failure modes, so make it an execution decision with a sensible default rather than forcing every caller to understand it.
Crashes, No Sound, or Screen Glitches?
Random freezes, missing sound and display glitches usually trace back to one bad driver. Find and replace yours safely.Free scan · under a minutePC Slower Than It Used to Be?
A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11Test the schema as an interface
- Start with the smallest valid object and confirm the scraper reaches its first request.
- Omit each optional field and verify that the documented default is actually applied.
- Submit empty strings, out-of-range numbers, empty arrays and malformed nested objects; each should produce a useful validation error.
- Try an undeclared property and confirm the result matches your intentional strictness policy.
- Launch through every supported path—Console, API, CLI and scheduler—because UI prefills and runtime defaults can appear different.
- Run a compatibility fixture containing inputs saved by existing callers before publishing a breaking schema change.
Apify states that input failing validation is rejected before the Actor starts. Treat that boundary as a testable guarantee: no queue should be created and no target request should be issued for invalid input.
Operational details that belong in the design
Protect cost and target sites
Bound crawl counts, pagination depth and batch sizes. Defaults should be conservative enough for a first run, while maximums should reflect the capacity you can support. If a caller can provide many URLs, cap the array and explain how to split larger jobs.
Make retries safe
Prefer deterministic inputs and expose a stable run identifier or resume option only if the implementation supports it. Avoid accepting a free-form “retry everything” flag that can multiply traffic unexpectedly. Document whether changing a filter or page limit creates a new run or resumes an old one.
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Keep secrets out of ordinary fields
Authentication values, cookies and authorization headers need platform-appropriate secret handling. Do not use a prefilled example token, include secrets in descriptions, or write them to ordinary run logs. The schema should name the credential purpose without exposing its value.
Respect access rules
A valid schema does not grant permission to crawl a site. Check the target’s terms, robots directives, authentication requirements and applicable law before running a scraper. Make rate limits and allowed domains explicit where those controls are part of your implementation.
Common failures and fixes
| Symptom | Likely cause | Fix |
|---|---|---|
| The form shows a value, but an API run has none | A UI prefill was mistaken for a default | Set a real default or require the property; test an API launch with the field omitted. |
| Valid-looking JSON is rejected | Framework-specific schema syntax or an unsupported editor | Validate with the framework’s own validator and remove assumptions imported from generic JSON Schema. |
| The crawler starts, then makes useless requests | Constraints are missing or applied only in scraper code | Add bounds, patterns, item schemas and cross-field checks before execution. |
| A new client breaks after a schema update | additionalProperties was tightened |
Review saved inputs, communicate the change and version the contract if necessary. |
| A rendered page has no records | The records came from a separate network request | Inspect the request and reproduce its method, URL, body, headers or form parameters; render only when required. |
| Runs are slow and expensive | Every job launches a browser for data available from an API response | Expose the structured request inputs and use direct retrieval where feasible. |
Or skip the browser setup
When the output you need is a page image or PDF rather than extracted records, ScreenshotNeo provides a single HTTP request. It accepts cookie and consent banners like a visitor, then removes more than 60 known consent platforms, newsletter popups and chat widgets before capture; each cleanup step can be disabled. Bot checks or CAPTCHAs, blank pages, timeouts, failed loads and cache hits are not billed, and response headers identify the page verdict and whether the request was billed.
Use the API examples in the ScreenshotNeo documentation. Replace the target URL as needed.
cURL
curl -G "https://api.screenshotneo.com/v1/shot" -d access_key=YOUR_API_KEY --data-urlencode url=https://stripe.com -o shot.webpPython
import requests
r = requests.get("https://api.screenshotneo.com/v1/shot", params={"access_key": "YOUR_API_KEY", "url": "https://stripe.com"}, timeout=90)
open("shot.webp", "wb").write(r.content)Node.js
const q = new URLSearchParams({ access_key: 'YOUR_API_KEY', url: 'https://stripe.com' });
const res = await fetch(`https://api.screenshotneo.com/v1/shot?${q}`);ScreenshotNeo also offers an MCP server with take_screenshot, get_page_info and capture_pdf tools for Claude, Cursor and other MCP clients. Every feature is available on every plan; 1,000 screenshots per month are free without a card, and paid plans start at $5 for 3,000 shots. Create a free ScreenshotNeo account.
The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Apify-specific limits and portability
Apify documents schema version 1 and a maximum Actor input-schema file size of 500 kB. Those are Apify platform facts, not universal limits for scraper frameworks. Keep schemas focused even below that ceiling: a smaller public contract is easier to review, migrate and present in generated documentation.
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
Portability requires translation. An Apify Actor schema’s editors, defaults and validation messages may have no direct equivalent in Scrapy or a custom command-line tool. Preserve the contract—names, types, requiredness and bounds—while mapping the presentation layer to the target framework.
Frequently Asked Questions
Should every scraper input be required?
No. Require only values without which a meaningful run cannot proceed; provide defaults for routine behavior and optional fields for legitimate variations.
Is an Apify Actor schema ordinary JSON Schema?
It is similar, but Apify documents extensions and differences. Use Apify’s validator instead of assuming every generic JSON Schema tool will accept or enforce it identically.
When should I expose a browser-rendering option?
Only after checking whether the target’s data comes from a reproducible network request. Use rendering when client-side execution or a browser-visible artifact is genuinely required.
The Bottom Line
Design the schema as a small public contract: typed fields, explicit required/default/prefill semantics, constraints that match reality, intentional strictness and a data-retrieval strategy chosen after inspecting the target. Validate it through every launch path before you publish it.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
