2026 AI API Relay Provider Comparison: How to Choose Among 7 of the Hottest Providers

If you're an AI developer, indie builder, or vibe coder in mainland China, you've probably already run into these headaches: OpenAI/Anthropic/Google official accounts are a pain to register for, payment requires a foreign-currency credit card, domestic access needs a proxy, and paying official rates for GPT-4-class models adds up fast. That's why "AI API relay" services exist — they buy upstream official account quota in bulk, build an OpenAI-compatible reselling panel, and let you pay with Alipay/WeChat, connect directly from mainland China, and call mainstream LLM APIs at friendlier prices.

Why These 7 Are Worth Watching

The relay market has ballooned over the past two years — dozens of providers are active at once, with names all over the map and marketing copy that's largely interchangeable ("lowest price on the market," "direct mainland connect," "99.99% SLA," "40% cheaper than going direct"…). How do we filter down to the ones actually worth your attention? Our screening approach:

• High-frequency exposure: providers that keep showing up and getting compared across multiple independent third-party reviews and buyer's-guide articles (CSDN, Zhihu, AtomGit, Sohu, IT Home, etc.), which suggests genuinely high market awareness and discussion volume;
• Differentiated positioning: covering as many different use cases as possible — individual developers/students, enterprise teams, multi-model benchmarking, domestic open-weight models, native multi-protocol support — rather than 7 providers all pitching the same thing;
• Publicly verifiable information: at least some of the model coverage, pricing model, and direct-connect status can be cross-checked against public sources, rather than resting on a single tagline.

By that standard, we picked SiliconFlow, OpenRouter, 4SAPI (Xinglian 4SAPI), PoloAPI, ShiyunApi, 147API (147AI), and Shenma Relay API. One important caveat: pricing, promotions, and SLA commitments in the relay industry change fast, and a lot of "reviews" out there are written by the provider itself or an affiliated party (sometimes literally "player and referee in one"). This piece sticks to publicly cross-verifiable information wherever possible, and explicitly flags any number we couldn't verify (things like "40% cheaper" or "99.7% success rate") as a vendor's own claim. Always check each provider's current official page for actual pricing and promotions.

4 Things to Check Before You Pick a Relay

Before going provider by provider, let's set the evaluation framework — the same lens we'll use for each one below:

One more industry-wide risk worth flagging: multiple Zhihu/forum discussions point out that the relay industry isn't especially mature yet, with reports of providers "disappearing overnight," "quietly cutting quotas," or "swapping in a cheaper model / misrepresenting specs." Some research even suggests a meaningful share of relay endpoints engage in some form of "quality substitution." This isn't to say all 7 providers here have these problems — it's a reminder that whichever one you pick, it's worth prioritizing a provider with a registered company entity, responsive support, and small pay-as-you-go top-ups, and running a small paid test before committing to a real integration.

1. SiliconFlow

SiliconFlow is a leading cloud platform for Chinese open-weight models, built around DeepSeek, Qwen, GLM, InternLM, and 100+ other open models, with its own inference engine and domestic-chip adaptation.

• Model support: one of the most complete relays for the mainstream Chinese open-weight model ecosystem, with some models available for free — great for developers who need the latest DeepSeek/Qwen releases;
• Pricing: pay-as-you-go, with the provider claiming "lowest prices anywhere," plus a publicly documented new-user and referral rebate program (both signup and invites earn trial credit) — one of the few relays that publishes its promo terms directly on its site instead of requiring you to contact sales;
• Stability/reputation: mainland servers with direct connect and no cross-border latency, frequently cited in comparison articles as the go-to for "high-concurrency real-time workloads," with relatively high community awareness and discussion volume;
• Promotions: new-user signup and referral rebates are publicly advertised, but exact amounts may change — check the official page for current terms;
• Why pick it: in one line — if your project leans heavily on domestic open-weight models like DeepSeek/Qwen and you want mainland direct-connect plus a controllable budget, SiliconFlow is nearly impossible to skip.

2. OpenRouter

OpenRouter is a cross-vendor, multi-model aggregation platform, claiming to aggregate 200-300+ models — one API key gets you access to nearly every major provider: OpenAI, Anthropic, Google, Meta, Mistral, and more.

• Model support: among the broadest model coverage of any relay, typically among the first to add newly released models — great for "multi-model benchmarking/model selection" use cases;
• Pricing: essentially official pricing passed through with a small markup (sources differ on the exact markup, anywhere from 1% to 25% has been cited), and new users typically get a small amount of free credit to try it out;
• Stability/reputation: has automatic failover — if an upstream model gets rate-limited or goes down, it can switch to a backup model automatically; highly internationalized with mature docs and developer community;
• Promotions: a small amount of free credit for new users — check the official page for specifics;
• Why pick it: in one line — if you need "one key to test every candidate model" for evaluation/prototyping, or your product is aimed at an overseas audience, OpenRouter's breadth of model coverage and failover capability are hard to replace; that said, its nodes are overseas, so mainland direct-connect performance is usually weaker than the other providers on this list — worth evaluating your own network conditions first.

3. 4SAPI (Xinglian 4SAPI)

4SAPI (Xinglian 4SAPI) markets itself around an "enterprise-grade self-healing routing system" and "enterprise-grade account pool," frequently ranking at or near the top in third-party comparison/buyer's-guide articles — one of the most visible providers on this list.

• Model support: full coverage of mainstream models (OpenAI/Claude/Gemini, etc.), with particular emphasis on multimodal scenarios (like AI comic/animation generation);
• Pricing: pay-as-you-go, with the provider claiming roughly "40% cheaper" than going direct to official pricing — that figure currently comes mainly from the provider's own blog posts, without independent third-party verification we could find, so treat it as a starting point and verify with your own testing;
• Stability/reputation: claims latency in the 20-300ms range, targeting high-concurrency scenarios like AI coding assistants and real-time customer service; "self-healing routing" implies millisecond-level failover when an upstream channel has issues; shows up often in industry comparisons, though worth noting some of those comparison articles originate from its own official blog — so there's a possible "grading its own homework" effect;
• Promotions: no public affiliate/rebate program found so far — check the official page for current promotions;
• Why pick it: in one line — if your use case is an AI coding assistant or multimodal real-time interaction and you're latency-sensitive, and you don't mind running a small test to verify the marketing numbers yourself, 4SAPI is the most visible provider in the market and worth adding to your shortlist.

4. PoloAPI

PoloAPI's positioning is a bit different from the others — it doesn't lead with "cheapest" or "most models," but rather "stability and multi-model balance," and is often described in comparison pieces as the "low-drama, can run long-term" option.

• Model support: supports multiple mainstream providers' models, with broad coverage;
• Pricing: pay-as-you-go, check the official site for exact rates; its differentiation isn't price, but rather usage analytics, audit trails, and other enterprise-governance features that make it easier for teams to manage multi-project usage;
• Stability/reputation: in several enterprise-focused write-ups, PoloAPI is often positioned as "stable but not necessarily cheapest," a reliable long-term option; some articles mention enterprise projects using it as a "backup line" — a sign its engineering maturity around failure-rate control and multi-model compatibility is fairly well regarded;
• Promotions: no public affiliate/rebate program found so far — see the official page for current offers;
• Why pick it: in one line — if you're a team/enterprise user who needs to fold a relay API into a real production workflow with usage auditing, and you don't want to switch providers often, PoloAPI's "engineering maturity first" positioning is worth prioritizing.

5. ShiyunApi

ShiyunApi's core differentiator is native three-protocol support — it natively supports OpenAI, Anthropic, and Gemini protocols simultaneously, rather than wrapping every model behind a single OpenAI-compatible layer.

• Model support: full coverage across all three protocols, which is especially friendly for projects calling the native Anthropic SDK directly (e.g., tools deeply integrated with the Claude Code ecosystem) or the native Gemini SDK — no need to rework your calling code just to fit a relay;
• Pricing: enterprise-oriented positioning; check the official site for exact rates — generally aimed at teams less sensitive to budget and more focused on stability and management tooling;
• Stability/reputation: claims 99.99% SLA with a full enterprise management suite — while the specific compensation-clause details aren't publicly documented, the combination of "native multi-protocol plus a high claimed SLA" scores relatively well among the enterprise-tier options on this list;
• Promotions: no public affiliate/rebate program found so far — see the official page for details;
• Why pick it: in one line — if your codebase already calls the Anthropic or Gemini native SDK directly (rather than an OpenAI-compatible format), ShiyunApi's native three-protocol support saves you a whole layer of adaptation work.

6. 147API (147AI)

147API (147AI) is another "mainline recommendation"-type provider that keeps showing up across industry comparisons, built around high interface compatibility and RMB-denominated enterprise-grade relay service.

• Model support: full coverage of mainstream models (OpenAI/Claude/Gemini, etc.);
• Pricing: RMB settlement, pay-as-you-go, check the official site for exact rates — for mainland developers, RMB settlement alone removes a lot of the hassle around exchange-rate swings and cross-border payment;
• Stability/reputation: frequently used as a baseline comparison point in "147AI vs. PoloAPI vs. Xinglian 4SAPI, which one should I pick" articles, suggesting it sits in the first tier of awareness among mainland developers; the provider also emphasizes "high interface compatibility, low migration cost";
• Promotions: no public affiliate/rebate program found so far — check the official page for current promotions;
• Why pick it: in one line — if you're already using another relay and want to switch without a major code rewrite, 147API's "high interface compatibility, low migration cost" positioning, combined with the convenience of RMB settlement, makes it a fairly safe migration target.

7. Shenma Relay API

Shenma Relay API's biggest calling card is sheer model count — the provider claims to cover 650+ models, reportedly the most in the industry, with mainland direct-connect and pay-as-you-go pricing.

• Model support: 650+ models, claimed to be the broadest coverage in the industry — appealing if you need access to niche/long-tail models rather than just the well-known GPT/Claude/Gemini set;
• Pricing: pay-as-you-go, check the official site for exact rates;
• Stability/reputation: mainland direct-connect; worth noting that different sources cite slightly different official domains, and the "650+ models" figure currently comes mainly from the provider's own claims — we'd recommend verifying the official URL and the actual model list before real use; in recent search results, Shenma Relay API comes up frequently in mainland developer discussions, and is the most-mentioned provider specifically under the "broadest coverage" niche;
• Promotions: no public affiliate/rebate program found so far — see the official page for current offers;
• Why pick it: in one line — if what you need isn't "a handful of flagship models running reliably" but rather "I want to try as many models as possible — including niche/long-tail ones — from one panel," Shenma Relay API's 650+ model coverage is the most targeted answer among these 7.

Bottom Line: How to Choose Among the 7

Condensing the analysis above into one-line recommendations by use case:

One last reminder: this piece draws on each provider's own official pages plus cross-referencing across multiple third-party reviews, and pricing, promotions, and SLA commitments will change over time — always check each provider's current official page. Given that reports of providers "disappearing overnight," "cutting quotas," or "swapping models" do exist in this industry, whichever one you choose, we'd recommend: run a small paid test first, confirm the actual results (speed, success rate, whether responses genuinely match the model you selected) meet your expectations, and only then scale up your commitment.