Stainless vs Vercel AI Gateway: LLM Gateways Comparison
Compare Stainless and Vercel AI Gateway side by side. Both are tools in the LLM Gateways category.
Updated March 10, 2026
The short answer
Choose Stainless if automates SDK dev.
Choose Vercel AI Gateway if zero markup on tokens with bring-your-own-key—transparent pricing.
Want to compare Stainless and Vercel AI Gateway on your own traffic?
Respan lets you trace LLM and agent calls across any model or framework, A/B test prompts on production traffic, and route requests across 250+ models through one gateway. Free tier covers 10K traces per month. Setup in 5 minutes, no credit card.
Quick Comparison
| Category | LLM Gateways | LLM Gateways |
| Pricing | paid | — |
| Best For | AI companies and developers building API clients | — |
| Website | stainlessapi.com | vercel.com |
| Key Features |
| — |
Pros & Cons: Stainless vs Vercel AI Gateway
- +Automates SDK dev
- +Type-safe code
- +Multi-language
- −Requires OpenAPI
- −Limited customization
- +Zero markup on tokens with bring-your-own-key—transparent pricing
- +USD 5 monthly free credit enables risk-free experimentation
- +Excellent developer experience with minimal setup
- +Automatic failover ensures reliability when providers fail
- −504 Gateway Timeout errors for long-running agents beyond hard limits
- −Pro plan maximum 300 seconds insufficient for complex agent workflows
- −Semantic caching relies only on HTTP headers—misses equivalent prompts
- −Vendor lock-in with custom middleware not portable to other platforms
Pricing: Stainless vs Vercel AI Gateway
- · Core features
- · Advanced features
- · Custom
- · Monthly credit
- · Zero markup on tokens
- · Basic features
- · Risk-free trial
- · Provider list pricing
- · Bring your own key
- · No platform fees
- · Unlimited access
- · Plus token costs
- · Agent capabilities
- · Production ready
About Stainless
Stainless automatically generates SDKs from OpenAPI specs. Creates production-quality type-safe SDKs in multiple languages.
About Vercel AI Gateway
Vercel AI Gateway is a production-ready LLM gateway that provides unified access to hundreds of AI models with built-in reliability, monitoring, and cost management. Available to every Vercel team account, the gateway offers a free USD 5 monthly credit plus pay-as-you-go pricing with zero markup on model tokens. When bringing your own API keys, Vercel charges no platform fees, offering tokens at provider list price. Vercel Agent is priced at USD 0.30 per action plus underlying token costs. The platform focuses on developer experience, enabling frontend developers to add LLM capabilities with minimal setup without managing provider-specific SDKs or credentials. Key features include unified API across providers, budget controls, usage monitoring, load balancing, and automatic failover. While praised for ease of use, transparent pricing, and reliability with automatic failover, Vercel AI Gateway faces criticism for infrastructure limitations including 504 Gateway Timeout errors for long-running agents, execution time constraints (15 seconds default, 300 seconds maximum on Pro), insufficient semantic caching relying only on HTTP headers, and vendor lock-in with custom middleware not easily portable to other platforms.
What is LLM Gateways?
Unified API platforms and proxies that aggregate multiple LLM providers behind a single endpoint, providing model routing, fallback, caching, rate limiting, cost optimization, and access control.
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