Caching.ai vs Portkey: AI Gateway or Prompt-Cache Optimizer?
Portkey is a full-featured AI gateway with simple and semantic response caching. Caching.ai is a focused proxy that keeps your provider prompt cache warm. Feature-by-feature comparison for 2026.
Short version: Portkey wants to be your AI control plane; Caching.ai wants to shrink your AI bill. If you're choosing between them you're really choosing between breadth (one gateway for routing, guardrails, observability and caching) and depth (one tool that squeezes everything out of provider prompt caching). (Disclosure: Caching.ai is our product; we've kept this factual — corrections → support@caching.ai.)
What each tool is
Portkey is a hosted AI gateway (with an open-source gateway core) that fronts hundreds of models: smart routing, automatic retries and fallbacks, guardrails, a prompt library, detailed observability — and caching in two modes, simple (exact match) and semantic (similarity match), both replaying stored responses with configurable TTLs.
Caching.ai is a drop-in proxy for Anthropic, OpenAI, Gemini and Grok that optimizes the provider-side prefix cache: hit-rate and wasted-spend analytics, automatic cache_control injection, cache-breaker diagnostics, economically-guarded cache warming through idle gaps, and per-key TTL auto-tuning. Benchmarked on 10,000+ real billed calls (public method and logs): 67% saved on sparse traffic, 89% on a shared-prefix batch, GPT-5.6 prefix hits restored from 0% to 97.8%+.
| Caching.ai | Portkey | |
|---|---|---|
| Category | Prompt-cache cost optimizer | Full AI gateway |
| Caching | Provider prefix-cache optimization | Simple + semantic response caching |
| Routing / fallbacks / guardrails | No | Yes — core product |
| Observability | Cache-focused metering (no bodies stored) | Full request logging & tracing |
| Freshness risk on cache hit | None — model always runs | Replayed responses; thresholds to tune |
| Savings accounting | Verified net savings vs list price, warming costs subtracted | Cost analytics on traffic |
| Open source | Apache-2.0 core (proxy + console) | Gateway core OSS; platform hosted |
| Pricing | 20% of verified savings; <$5/mo waived | Free tier + subscription |
Choose Portkey if…
- You want one hosted control plane: routing, fallbacks, guardrails, prompt management, logs.
- You operate many models/providers and value resilience features as much as cost.
- Your repeat traffic profile suits response/semantic caching (similar questions, tolerant of replay).
Choose Caching.ai if…
- Cost is the problem to solve, and your traffic is prefix-heavy (agents, copilots, chatbots, big system prompts).
- You want breakpoints, warming and TTL choices handled automatically — and proven on the bill, not promised.
- You prefer no prompt bodies stored by default, and pricing that only triggers when verified savings exist.
The honest bottom line
These tools fail differently: choosing Portkey and skipping prefix optimization leaves the provider's 90% discount partly uncollected; choosing Caching.ai alone leaves you without routing and guardrails if you need them. Some teams run Portkey for control-plane concerns and still point high-volume Anthropic/OpenAI traffic through Caching.ai for the cache math. Start from your bill: if cached-token line items are small and prefix-shaped waste is big, depth wins. Context: Top 7 LLM caching tools · prompt vs semantic caching.
Frequently asked questions
What's the main difference between Portkey and Caching.ai?
Scope. Portkey is a broad AI gateway — routing, fallbacks, guardrails, observability, prompt management, plus simple and semantic response caching. Caching.ai does one thing deeply: it maximizes the provider-side prompt-cache discount with analytics, automatic breakpoints, cache warming and TTL auto-tuning. Breadth vs depth.
Does Portkey's semantic cache replace prompt caching?
No. Portkey's caches replay stored responses for identical or similar requests. Prompt caching is the provider billing ~10% for re-sent prompt prefixes while still generating fresh answers. A semantic cache does nothing for your prefix hit rate — the two mechanisms are complementary.
Which is cheaper, Portkey or Caching.ai?
They price differently rather than one being cheaper: Portkey uses free-tier plus subscription pricing you pay regardless of outcome, while Caching.ai charges 20% of verified net savings (warming costs subtracted) and waives fees under $5/month — if it saves you nothing, it costs nothing.