AI API Router Directory

xAI (founded by Elon Musk) offers the official API for the Grok series of LLMs. Known for leading benchmarks in coding and reasoning, the Grok-4.6 flagship model is available via an OpenAI-compatible API, featuring low-latency inference and high agentic tool-calling capabilities.

No permanent free tier; ~$25 promo credit on signup (30-day expiry, varies by region/promotion). $150/mo data-sharing credits still listed by 2026 guides despite mid-2025 end reports — rely on what the console shows.

Api.airforce is a unified AI model aggregator reselling access to 100+ models from Anthropic, OpenAI, and xAI. It offers a large selection of free models (including Grok-3 and Claude 3.7) alongside paid subscription tiers for higher throughput.

55 free tier models including Grok-3, Claude 3.7, Qwen3, Kimi-K2, Gemini 2.5 Flash, DeepSeek-V3

Grok Build is xAI's terminal coding agent, installed from x.ai/cli and documented at docs.x.ai/build, running on grok-4.6. The official CLI page states the tool is available to try for free and the client is open source, while xAI's developer pricing page meters every request at API token rates: grok-4.6 costs $2.00 per million input tokens, $0.50 per million cached input tokens and $6.00 per million output tokens for prompts under 200k tokens, rising to $4.00 / $1.00 / $12.00 once a request reaches the long-context threshold.

No numeric free allowance is stated - x.ai/cli says only that Grok Build is available to try for free (checked 2026-09-16).

web-cookie access — wraps the provider web app (unofficial). Paste the full grok.com cookie line from DevTools → Application → Cookies. Include both `sso` and `sso-rw` (e.g. `sso=...; sso-rw=...`) — Grok's anti-bot rejects `sso` on its own. 7 models tracked (via OpenRouter catalog).

A free tier is available; the exact credit value is not quantified.

Zylo API provides a unified OpenAI-compatible gateway to models from Anthropic, OpenAI, Google, and more with zero token markup. Billing is based on base per-token rates deducted from a prepaid balance. A flat platform fee applies when adding credits.

No public free-tier information found in the source reference; treat free-tier availability as unverified rather than confirmed absent.

OAuth access — sign-in with your existing account. Sign in with xAI to use api.x.ai models such as Grok 4.5. This is separate from Grok Build JWT sessions, which use cli-chat-proxy.grok.com and grok-build model aliases. 7 models tracked (via OpenRouter catalog).

A free tier is available; the exact credit value is not quantified.