String is the better fit when a fixed list of protected pages must return consistently. ZenRows is the better fit when you want Fetch, structured extraction, large batch jobs, residential proxies, and interactive browser sessions on one credit balance. In the September 16, 2026 Web Data Frontier Benchmark, String returned verified content on 97.0% of 500 requests. ZenRows Fetch, with JavaScript rendering and premium proxies enabled, returned it on 41.2%.
ZenRows still wins meaningful cases. Its Growth plan prices a basic successful page at about $0.14 per 1,000, below String Growth's $0.20 usage rate. It beat String on Neiman Marcus, Allegro, and Booking.com. Its MCP server exposes batch jobs and a full browser-control tool family that String's MCP server does not.
Last updated September 22, 2026. Benchmark figures come from the September 16, 2026 run; see /benchmark. ZenRows product, pricing, credit, Adaptive Stealth, billing, Batch, Browser Sessions, Extract, and MCP claims were checked against its published pricing page, Fetch reference, billing FAQ, Batch documentation, Browser Sessions documentation, Extract documentation, and MCP documentation on August 31, 2026.
| String | ZenRows | |
|---|---|---|
| Product shape | One fetch API, plus search, sitemap crawling, remote Chrome, and MCP | Fetch, Extract, Batch, Browser Sessions, residential proxies, and MCP |
| Benchmark path | String selects the request or browser path | JavaScript rendering plus premium proxies, 25 credits per success |
| Benchmark success | 97.0% (485/500) | 41.2% (206/500) |
| Failure-aware latency score | 7.06s, 1st of 16 | 18.80s, 9th of 16 |
| Sites passed on no attempts | 2 of 100 | 50 of 100 |
| Entry offer | 5,000 free requests; Starter $20 plus usage | 5,000 free monthly credits, no card |
| Roughly $100 tier | Growth $100 plus $0.20 to $4.00 per 1,000 verified requests | No $100 plan; Launch $57 for 250,000 credits, Growth $165 for 1.2 million |
| Billing | Verified content only | Successful requests only; 404 and 410 count as success |
| Best fit | Protected pages that must return consistently | One platform for Fetch, batch jobs, extraction, and interactive browser work |
The Web Data Frontier Benchmark sends every provider the same 100 URLs five times. A response passes only when it contains a marker from the real page. A CAPTCHA or block page returning HTTP 200 still fails. The September run made 8,000 live requests across 16 providers.
String built the benchmark and sells the product that ranked first. The test is public so that conflict is inspectable: the target list and pass criteria, ZenRows adapter, and complete results JSON are available for review.
| Provider | Successful requests | Success rate | Latency score |
|---|---|---|---|
| String | 485/500 | 97.0% | 7.06s |
| ZenRows | 206/500 | 41.2% | 18.80s |
The latency score is failure-aware. For each target it takes the p75 of successful attempts; a provider that never returns the page inherits the p75 of providers that did. That prevents a fast block page from looking like good performance.
The ZenRows adapter sets js_render=true and premium_proxy=true. ZenRows' current Fetch reference prices that combination at 25 credits per successful request.
ZenRows also offers mode=auto, or Adaptive Stealth Mode. It starts with the cheapest viable setup, then escalates to JavaScript rendering or premium proxies only when needed. Failed attempts inside that escalation are free, and the customer pays for the configuration that succeeds. Auto mode could lower the credit mix on easy pages, but the benchmark did not record what it would choose for each target.
The 41.2% result is a measured result for ZenRows Fetch with both strong flags on. It is not a claim about ZenRows Browser Sessions, which expose a real browser over CDP for Puppeteer or Playwright and bill bandwidth plus session time. Interactive browser work is a different product and was not in this Fetch comparison.
ZenRows returned nothing on all five attempts for 50 sites. String returned content on 48 of those 50, and passed 47 of them on every attempt. The two shared shutouts were Temu and Idealista.
The misses are not limited to the hardest targets. ZenRows returned nothing on GitHub, arXiv, Bing, CoinMarketCap, Google Search, Yahoo Finance, Kayak, Zoopla, DigiKey, and every ticketing site in the suite.
ZenRows won one target outright. It cleared Allegro on all five attempts where String passed four. The three wins it held in August are down to that one: String now returns Neiman Marcus on every attempt, and both products clear Booking.com.
| Anti-bot system | String | ZenRows |
|---|---|---|
| Cloudflare | 100% | 25.3% |
| Akamai | 98.0% | 47.0% |
| DataDome | 92.6% | 63.2% |
| PerimeterX | 100% | 75.6% |
PerimeterX is ZenRows' strongest named category at 75.6%, up from 44.4% in August, and DataDome follows at 63.2%, ahead of six higher-ranked providers. Cloudflare is its weakest of the four, even though the adapter already enabled both premium proxies and rendering. String's largest lead is Cloudflare at 74.7 points.
ZenRows' working range is more visible by industry. It passed 55.6% of news and finance requests, 54.0% of marketplace requests, 50.6% of retail requests and 25.0% of social requests. It returned nothing across the ticketing and developer-and-research categories. The product can fit a target list even when the aggregate does not, but that fit has to be tested.
ZenRows is a broader web-data platform. Fetch returns HTML, Markdown, text, JSON, screenshots, or PDFs and handles proxies, rendering, sessions, headers, and Adaptive Stealth Mode. Extract is a beta that returns maintained structured JSON on a curated domain set. Batch accepts up to 100,000 URLs in one job, schedules recurring work, retries transient failures, and stores results.
Browser Sessions connect existing Puppeteer or Playwright code to hosted browsers with residential proxies, geotargeting, and interactions. ZenRows publishes more than 55 million residential IPs across 190-plus countries in its product documentation. Those are genuine product advantages over a fetch-only comparison.
String is narrower. Send a URL to the Web Access API and get Markdown, HTML, or JSON. Proxy rotation, fingerprinting, CAPTCHA solving, and browser escalation happen behind the endpoint. String also provides search, an asynchronous sitemap crawl, remote Chrome over CDP, and a hosted MCP server.
Both providers support agents, but ZenRows exposes the wider tool surface. String is in the official registry as ai.usestring/web-access, with fetch, search, and sitemap tools. The open-source ZenRows MCP server runs remotely at https://mcp.zenrows.com/mcp or locally through @zenrows/mcp. Its tool catalog covers scrape, batch submission and results, browser navigation, clicks, forms, JavaScript, cookies, storage, tabs, screenshots, and PDFs. ZenRows wins MCP breadth.
The live ZenRows pricing page lists Free at 5,000 credits per month, Build at $16 for 45,000, Launch at $57 for 250,000, Growth at $165 for 1.2 million, and Scale at $456 for 5 million. Every plan shares its balance across Fetch, Extract, Batch, Browser Sessions, and residential bandwidth.
Fetch and Batch use the same weights:
| ZenRows request | Credits | Build, per 1,000 | Launch, per 1,000 | Growth, per 1,000 |
|---|---|---|---|---|
| Basic page | 1 | $0.36 | $0.23 | $0.14 |
| JavaScript rendering | 5 | $1.78 | $1.14 | $0.69 |
| Premium proxy | 10 | $3.56 | $2.28 | $1.38 |
| JavaScript plus premium proxy | 25 | $8.89 | $5.70 | $3.44 |
ZenRows' pricing FAQ says failed attempts never charge and real 404 or 410 responses count as usable, billable results. Its general billing FAQ says the same. The distinction matters: a target page that genuinely does not exist bills, while a blocked attempt does not.
Browser Sessions use another meter on the same balance. The Browser Sessions pricing section lists 25,000 credits per GB plus 5 credits per session minute. This comparison does not convert that into a per-page rate because page weight and session reuse determine the answer.
String charges a subscription plus requests that return verified content. The first 5,000 requests are free. Starter is $20 per month and Growth is $100. Growth rates are:
| Fetch path | Price per 1,000 verified requests |
|---|---|
| Request, standard proxy | $0.20 |
| Browser, standard proxy | $1.00 |
| Request, premium proxy | $2.00 |
| Browser, premium proxy | $4.00 |
The honest price comparison runs both ways. ZenRows Growth's $0.14 basic rate undercuts String Growth's $0.20 usage rate, and its $3.44 protected rate undercuts String's $4.00 browser-on-premium path. String's $2.00 premium-request path undercuts the same ZenRows protected rate. ZenRows costs $165 before usage; String Growth costs $100 plus usage. The exact winner depends on volume and which paths succeed.
Do not divide either provider's success-billed rate by benchmark success. A blocked request costs neither provider anything. Success rate answers whether the page arrives. The rate card answers what a successful response costs. The broader best web scraping APIs, 16 compared keeps those questions separate.
Keep ZenRows for Batch, Extract, browser sessions, or inexpensive basic pages and send the Fetch misses through String. The reverse can work too: use String for protected retrieval and ZenRows for structured extraction or agent-driven interactions.
Both products include a free recurring allowance. Test ZenRows Fetch in both Adaptive Stealth and explicit 25-credit modes, plus Browser Sessions where the task truly needs interaction, against the same representative URLs before changing production traffic.
If ZenRows is one option among several, the ZenRows alternatives comparison places six substitutes next to the same benchmark.
On the September 2026 Fetch benchmark, yes. String returned verified content on 97.0% of 500 requests and ZenRows on 41.2%, even though ZenRows ran with JavaScript rendering and premium proxies. ZenRows beat String on Allegro, and its Browser Sessions were not tested.
Not always. ZenRows Growth's fully used basic-page rate is about $0.14 per 1,000 successes, below String Growth's $0.20 usage rate. ZenRows' 25-credit protected path is about $3.44, below String's $4.00 browser-on-premium path but above its $2.00 premium-request path. ZenRows Growth costs $165 per month; String Growth costs $100 plus usage.
No. ZenRows bills only successful requests. Its live pricing page and billing FAQ say 404 and 410 responses count as successful results, while failed and retried attempts are free. String bills only when verified content returns.
No. It tested Fetch with js_render=true and premium_proxy=true, the 25-credit configuration. Adaptive Stealth Mode changes the cost mix by starting cheap and escalating. Browser Sessions provide an interactive CDP browser with a separate bandwidth-and-time meter and may behave differently.
String on the failure-aware benchmark score: 7.06 seconds against ZenRows' 18.80. On the 30 sites both products returned in full, the median per-site time was 2.80 seconds for String and 7.70 for ZenRows. That score includes the cost of targets a provider fails and should not be read as a raw response-time promise for every successful page.
ZenRows for breadth. Its hosted and open-source MCP server includes scrape, Batch, and a full browser-control family. String's hosted MCP server focuses on fetch, search, and sitemap tools. MCP breadth does not change the measured Fetch coverage gap.
Stay when you need its broader platform, your target list fits its news, marketplace, or retail strengths, or basic-page pricing and enterprise governance matter more than the benchmark aggregate. ZenRows also beat String on Neiman Marcus, Allegro, and Booking.com.
Yes. The benchmark repository, ZenRows adapter, and August results file are public. A full run makes thousands of billable requests, so begin with a subset.
