JavaScript proxy service for cross-domain API requests

Developers need to make API calls from browsers that are blocked by CORS policies. A proxy service that handles cross-domain requests safely is still needed.

YC GraveyardJun 1, 2011ToolDevSource

FL score

out of 100

Verdict

VALIDATE

high confidence

Competition

competitors found, nascent market, funded players

Trend

1 community mentions

A JavaScript proxy service for reliable cross-domain API requests that solves developer CORS frustrations, but needs a sharper niche against existing funded competitors.

The pain

Developers constantly struggle with CORS errors when making API requests from browsers, and existing free proxy services are notoriously slow, unreliable, frequently suffer downtime, or impose strict rate limits, hindering development and breaking production applications.

The gap

While many free and some paid proxy services exist, there's a perceived gap in consistently reliable, production-grade, and perhaps specialized CORS proxies that truly cater to specific developer needs beyond just basic functionality. Funded competitors are already targeting 'production-ready' solutions, making a generic 'more reliable' pitch insufficient.

Build angle

Focus on extreme reliability, fast performance, and a generous free tier for specific developer use cases (e.g., Notion power users building advanced dashboards, specific frameworks like React/Vue apps hitting legacy APIs) with clear upgrade paths for production-grade features like domain allowlisting, advanced logging/analytics, and enhanced security controls, all built efficiently on serverless functions.

Strengths

Real, specific, and severe pain for developers, talked about frequently online.
Clear signals that people are willing to pay for reliability and features (paid tiers from competitors, Reddit discussions).

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Next steps

Conduct in-depth user interviews with developers who have recently expressed frustration with existing CORS proxies. Identify *specific* pain points or unmet needs that current 'production-ready' solutions fail to address.
Deep dive into competitor offerings (Corsfix, RapidAPI's proxy, CORS.lol) to find a clear, defensible, and unserved feature or audience niche.
Explore niche communities (e.g., specific framework users, particular API consumers) to identify a segment with acute, unique CORS proxy needs.
Build a landing page to capture interest and gauge demand for a *specific* angle, perhaps offering unique features or a unique service level agreement (SLA) not offered by competitors.

Fly Labs Method

Is the pain real, is there a gap, is it the right time, can one person build it.

Problem clarity: 28
Solution gap: 14
Willingness to pay: 18
Buildability: 18

The problem is real, painful, and specific, but the market already has several competitors, including funded ones trying to solve the exact reliability gap. Solo buildability is high, and payment signals exist for a truly reliable solution, but strong differentiation is key.

Value Equation

Dream outcome and how likely it feels, against the time and effort it costs.

Strong market demand and good timing, but significant risk in differentiation against existing, funded competitors. The value proposition of reliability is key but hard to establish a unique moat.

One-Person Business

Curiosity pull, identity fit, and a path from free value to paid for a solo creator.

A clear, well-understood problem with good creator fit and monetization potential, but requires significant effort to achieve simplicity, differentiation, and leverage in a competitive market.

Viral Frameworks

Hook strength, shareability, and how cheaply it can be tested.

Strong target audience and value proposition with clear distribution and business model. However, the assumption risk of competing with existing players on reliability is high, requiring more pre-build validation.

Builder Lens

Evidence the problem exists, timing, defensibility, and a model that fits on a napkin.

Clear, desperate demand for a reliable solution, but future fit beyond basic proxying needs to be considered to maintain long-term relevance.

Why this verdict

The idea scores well on problem clarity, buildability, and willingness to pay. However, the 'solution gap' is challenging. While free proxies are poor, funded competitors are actively addressing the pain points of reliability and production-readiness. For a solo builder, directly competing on 'better reliability' is a race to the bottom. A successful execution requires discovering a highly specific, underserved niche or a unique value proposition that existing players are missing, which needs further validation before committing to a full build.

Five lenses, one composite. How scoring works

The angle

This weekend

Conduct in-depth user interviews with developers who have recently expressed frustration with existing CORS proxies. Identify *specific* pain points or unmet needs that current 'production-ready' solutions fail to address.
Deep dive into competitor offerings (Corsfix, RapidAPI's proxy, CORS.lol) to find a clear, defensible, and unserved feature or audience niche.
Explore niche communities (e.g., specific framework users, particular API consumers) to identify a segment with acute, unique CORS proxy needs.
Build a landing page to capture interest and gauge demand for a *specific* angle, perhaps offering unique features or a unique service level agreement (SLA) not offered by competitors.

Who is already there, nascent market

cors.sh
Open-source CORS proxy service that allows bypassing browser CORS restrictions for API requests. Provides free test keys for 3 days and free licenses for open-source projects.
Pricing: free (with limits and keys)
corsproxy.io
Public CORS proxy service for making cross-domain API requests from browsers.
Pricing: free
allorigins.win
Free public API proxy that handles CORS by fetching and proxying content.
Pricing: free
thingproxy.freeboard.io
Simple public CORS proxy for fetching resources across domains.
Pricing: free
CorsfixVisit
A fast, unlimited, and production-ready CORS proxy with features like domain allowlisting, secrets management, and cached responses. It aims to be a modern and secure platform for solving CORS errors.
Pricing: Free tier for development (unlimited requests, unlimited web applications, 25 GB data transfer, 60 RPM per IP). Growth: Unlimited requests, unlimited web applications, 100 GB data transfer, 120 RPM per IP. Scale: Unlimited requests, unlimited web applications, 500 GB data transfer, 180 RPM per IP.
CORS AnywhereVisit
A popular open-source CORS proxy that allows bypassing CORS errors by prefixing the URL. It's self-hostable and has been a go-to tool for developers for years.
Pricing: Free (open-source, self-hostable). Demo server access is strictly limited since 2021.
RapidAPI's Cors ProxyVisit
A CORS proxy offered through RapidAPI, providing different tiers based on the number of requests.
Pricing: Basic: $0.00/month (25 requests/month). Pro: $2.99/month (1,000 requests/month). Ultra: $5.00/month (8,000 requests/month). Mega: $25.00/month (50,000 requests/month).
CORS.lolVisit
A super easy and open-source CORS proxy, offering unlimited requests and no rate limits for its lifetime plan.
Pricing: Lifetime: $35 (no rate limit, unlimited requests, up to 100 MB per request). A rate-limited free option is also available.
XDomainVisit
A pure JavaScript CORS alternative that doesn't require server-side configuration, working by adding a proxy.html file on the target domain.
Pricing: N/A (open-source library)
Whatever OriginVisit
An open-source CORS proxy that supports basic proxying with GET requests and provides JSONP support.
Pricing: N/A (open-source library)
Proxy (Identity Signal)FundedVisit
A startup focused on a universal identity signal for frictionless access in the physical world, not directly a JavaScript proxy for API requests.
Pricing: N/A

Funded players

Gaps they leave open

high uptime/reliability without frequent downtime
generous rate limits for production use
paid tiers for enterprise/security
managed service with SLAs
customizable security and logging controls

What people say, 1 mentions

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