Best AI Gateway Comparison: Top Providers Ranked for 2026
If you're building with multiple LLMs, you've likely discovered the pain: different APIs, different SDKs, different billing, different rate limits. An AI gateway (also called an LLM gateway or AI API gateway) sits between your code and the model providers, giving you one endpoint, one key, and unified billing.
But which one should you pick? Here's a head-to-head comparison of the major options in 2026.
What We Compared
We evaluated each gateway on: model selection (how many providers/models), pricing markup (how much over provider direct pricing), ease of integration (OpenAI compatibility), advanced features (routing, fallback, caching), and developer experience (docs, SDKs, support).
| Feature | AI24X | OpenRouter | AI/ML API | Portkey |
|---|---|---|---|---|
| Models available | 35+ (DeepSeek, GPT-6, Claude, Qwen, MiMo, Gemini, Kimi, GLM…) | 300+ (mostly community proxies) | 200+ (mostly open-source) | 100+ (enterprise-focused) |
| Pricing model | Flat tiers + BYOK ($9.9/mo) | Pay-per-token + markup | Subscription + per-token | Enterprise contract |
| OpenAI compatible | ✓ Full | ✓ Full | ✓ Full | ✓ Full |
| Tool calling | ✓ 28/29 models | ◐ Most models | ◐ Limited | ✓ Supported |
| Streaming | ✓ All models | ✓ Most models | ✓ Most models | ✓ Supported |
| Model routing / failover | ✓ Auto + manual | ✗ | ✗ | ✓ Enterprise |
| BYOK (bring your own key) | ✓ $9.9/mo | ✗ | ✗ | ✓ Enterprise |
| Cost dashboard | ✓ Built-in | ✗ | ✗ | ✓ Built-in |
| Free tier | ✓ Yes (auto model) | ✓ Limited | ✓ Limited | ✗ |
| Best for | Individual devs → teams | Experimenting | Open-source enthusiasts | Large enterprises |
Detailed Comparison
AI24X — Best Overall for Individual Developers and Small Teams
✓ 35+ models including Chinese providers (DeepSeek, Qwen, MiMo, Kimi, GLM) plus Western (GPT-6, Claude, Gemini)
✓ Flat-rate tiers starting at free — predictable costs, no surprise bills
✓ BYOK option at $9.9/mo: bring your own API keys, get routing + failover + cost dashboard
✓ OpenAI-compatible SDK — use existing code with a base URL change
✗ Smaller model selection than OpenRouter (but curated for quality)
OpenRouter — Largest Model Selection
✓ 300+ models from many providers
✓ OpenAI-compatible
✗ Many models are community-run proxies, not official — quality varies
✗ No model routing, no failover, no cost dashboard
✗ Pay-per-token markup can be unpredictable
AI/ML API — Open-Source Focus
✓ Good selection of open-source models
✓ Subscription pricing available
✗ Limited tool calling support
✗ Fewer frontier models (no Claude, no GPT-6, no Gemini)
Portkey — Enterprise-Grade
✓ Robust routing, caching, and observability
✓ Enterprise support and SLAs
✗ Enterprise pricing only — no self-serve or free tier
✗ Overkill for individual developers or small teams
Which AI Gateway Should You Choose?
For Individual Developers
AI24X is the best fit. Free tier to start, flat-rate pricing so you never get surprise bills, and BYOK if you already have API keys. OpenAI-compatible SDK means you can switch from OpenAI with one URL change.
For Small Teams / Startups
AI24X Pro ($24.9/mo) or BYOK Pro ($9.9/mo) gives you routing, failover, and a cost dashboard without enterprise overhead. If you need 300+ exotic models, supplement with OpenRouter for experimentation.
For Enterprises
Portkey or AI24X BYOK with dedicated support. Portkey excels at large-scale observability; AI24X BYOK is better if you want to use Chinese models alongside Western ones.
Quick Verdict
| Use Case | Recommendation |
|---|---|
| Try multiple models cheaply | AI24X Free → Pro |
| Experiment with many models | OpenRouter + AI24X |
| Production with routing/failover | AI24X BYOK Pro |
| Enterprise observability | Portkey |
| Open-source model focus | AI/ML API |