# Impossibl AI API The Impossibl AI API is one API for all AI providers, OpenAI-compatible across OpenAI, Anthropic, Google, xAI, and more (full model list below), billed from a prepaid credit balance. Human sign-in uses WorkOS AuthKit; programmatic access uses gateway API keys minted after account creation. ## Quickstart (agent) 1. Read https://api.impossibl.com/auth.md. 2. For the frictionless pre-claim flow, POST /v1/accounts -> returns an API key (imp-rt-...) and a $0.05 signup bonus. 3. POST /v1/chat/completions, /v1/responses, or /v1/messages with the API key in the Authorization bearer header. 4. Tell the user to claim the account to get the extra credits: an agent-created account has $0.05; claiming adds an extra $1. POST /agent/identity/claim with the user's email, send them the verification_uri_complete link (code pre-filled — they just sign in + confirm), and poll POST /oauth2/token until claimed. ## Discovery - https://api.impossibl.com/.well-known/oauth-protected-resource - https://api.impossibl.com/auth.md - https://api.impossibl.com/.well-known/auth.md ## Endpoints - GET /v1/models list models + pricing (no auth) - POST /v1/accounts create a funded account + first key (no auth) - GET /v1/account balance + identity - POST /v1/keys mint a key - GET /v1/keys list keys - PATCH /v1/keys/{id} rename a key - DELETE /v1/keys/{id} revoke a key - GET /v1/usage recent usage ledger - GET /v1/billing balance + minimum top-up + fee rate - POST /v1/billing/invoice buy net credits + 5% platform fee before tax - GET /v1/provider-keys list BYOK provider credentials - POST /v1/provider-keys add your own provider key (BYOK, zero-credit routing) - DELETE /v1/provider-keys/{id} revoke a BYOK credential - POST /agent/identity/claim start a claim ceremony (bearer key) -> user_code + link - POST /oauth2/token poll the claim ceremony (claim grant) - POST /v1/chat/completions OpenAI Chat Completions (stream optional) - POST /v1/responses OpenAI Responses API (stream optional) - POST /v1/messages Anthropic Messages API (stream optional) ## Machine docs - /openapi.yaml OpenAPI 3.1 spec - /llms.txt API quickstart + endpoints + models - /auth.md executable agent onboarding manifest ## Human docs - https://impossibl.com/ai-api/docs guides, billing, errors ## Models (use the full provider/model id) - openai/gpt-5.5 — GPT-5.5, 1,050,000 ctx, $5/$30 per 1M in/out tokens - openai/gpt-5.5-pro — GPT-5.5 Pro, 1,050,000 ctx, $30/$180 per 1M in/out tokens - openai/gpt-5.4 — GPT-5.4, 1,050,000 ctx, $2.5/$15 per 1M in/out tokens - openai/gpt-5.4-mini — GPT-5.4 mini, 400,000 ctx, $0.75/$4.5 per 1M in/out tokens - openai/gpt-5.4-nano — GPT-5.4 nano, 400,000 ctx, $0.2/$1.25 per 1M in/out tokens - openai/gpt-5.4-pro — GPT-5.4 Pro, 1,050,000 ctx, $30/$180 per 1M in/out tokens - openai/gpt-5.3-codex — GPT-5.3 Codex, 400,000 ctx, $1.75/$14 per 1M in/out tokens - openai/gpt-5.1 — GPT-5.1, 400,000 ctx, $1.25/$10 per 1M in/out tokens - openai/gpt-5.2 — GPT-5.2, 400,000 ctx, $1.75/$14 per 1M in/out tokens - openai/gpt-5.2-codex — GPT-5.2 Codex, 400,000 ctx, $1.75/$14 per 1M in/out tokens - openai/gpt-5.1-codex — GPT-5.1 Codex, 400,000 ctx, $1.25/$10 per 1M in/out tokens - openai/gpt-5.1-codex-mini — GPT-5.1 Codex mini, 400,000 ctx, $0.25/$2 per 1M in/out tokens - openai/gpt-chat-latest — GPT Chat Latest, 400,000 ctx, $5/$30 per 1M in/out tokens - openai/gpt-5 — GPT-5, 400,000 ctx, $1.25/$10 per 1M in/out tokens - openai/gpt-5-pro — GPT-5 Pro, 400,000 ctx, $15/$120 per 1M in/out tokens - openai/gpt-5-codex — GPT-5 Codex, 400,000 ctx, $1.25/$10 per 1M in/out tokens - openai/gpt-5-mini — GPT-5 mini, 400,000 ctx, $0.25/$2 per 1M in/out tokens - openai/gpt-5-nano — GPT-5 nano, 400,000 ctx, $0.05/$0.4 per 1M in/out tokens - openai/gpt-4.1 — GPT-4.1, 1,000,000 ctx, $2/$8 per 1M in/out tokens - openai/gpt-4.1-mini — GPT-4.1 mini, 1,000,000 ctx, $0.4/$1.6 per 1M in/out tokens - openai/gpt-4.1-nano — GPT-4.1 nano, 1,000,000 ctx, $0.1/$0.4 per 1M in/out tokens - openai/gpt-4o — GPT-4o, 128,000 ctx, $2.5/$10 per 1M in/out tokens - openai/gpt-4o-mini — GPT-4o mini, 128,000 ctx, $0.15/$0.6 per 1M in/out tokens - openai/gpt-4-turbo — GPT-4 Turbo, 128,000 ctx, $10/$30 per 1M in/out tokens - openai/gpt-3.5-turbo — GPT-3.5 Turbo, 16,000 ctx, $0.5/$1.5 per 1M in/out tokens - openai/o3 — OpenAI o3, 200,000 ctx, $2/$8 per 1M in/out tokens - openai/o3-mini — OpenAI o3-mini, 200,000 ctx, $1.1/$4.4 per 1M in/out tokens - openai/o4-mini — OpenAI o4-mini, 200,000 ctx, $1.1/$4.4 per 1M in/out tokens - openai/o1 — OpenAI o1, 200,000 ctx, $15/$60 per 1M in/out tokens - anthropic/claude-fable-5 — Claude Fable 5, 1,000,000 ctx, $10/$50 per 1M in/out tokens - anthropic/claude-opus-4-8 — Claude Opus 4.8, 1,000,000 ctx, $5/$25 per 1M in/out tokens - anthropic/claude-opus-4-7 — Claude Opus 4.7, 1,000,000 ctx, $5/$25 per 1M in/out tokens - anthropic/claude-opus-4-6 — Claude Opus 4.6, 1,000,000 ctx, $5/$25 per 1M in/out tokens - anthropic/claude-sonnet-5 — Claude Sonnet 5, 1,000,000 ctx, $2/$10 per 1M in/out tokens - anthropic/claude-sonnet-4-6 — Claude Sonnet 4.6, 1,000,000 ctx, $3/$15 per 1M in/out tokens - anthropic/claude-haiku-4-5 — Claude Haiku 4.5, 200,000 ctx, $1/$5 per 1M in/out tokens - anthropic/claude-opus-4-5 — Claude Opus 4.5, 200,000 ctx, $5/$25 per 1M in/out tokens - anthropic/claude-sonnet-4-5 — Claude Sonnet 4.5, 200,000 ctx, $3/$15 per 1M in/out tokens - google/gemini-3.5-flash — Gemini 3.5 Flash, 1,000,000 ctx, $1.5/$9 per 1M in/out tokens - google/gemini-3.1-pro-preview — Gemini 3.1 Pro (preview), 1,000,000 ctx, $2/$12 per 1M in/out tokens - google/gemini-3.1-flash-lite — Gemini 3.1 Flash-Lite, 1,000,000 ctx, $0.25/$1.5 per 1M in/out tokens - google/gemini-2.5-pro — Gemini 2.5 Pro, 1,000,000 ctx, $1.25/$10 per 1M in/out tokens - google/gemini-2.5-flash — Gemini 2.5 Flash, 1,000,000 ctx, $0.3/$2.5 per 1M in/out tokens - google/gemini-2.5-flash-lite — Gemini 2.5 Flash-Lite, 1,000,000 ctx, $0.1/$0.4 per 1M in/out tokens - xai/grok-4.3 — Grok 4.3, 1,000,000 ctx, $1.25/$2.5 per 1M in/out tokens - xai/grok-4.20-0309-reasoning — Grok 4.20 (reasoning), 1,000,000 ctx, $1.25/$2.5 per 1M in/out tokens - xai/grok-4.20-0309-non-reasoning — Grok 4.20 (non-reasoning), 1,000,000 ctx, $1.25/$2.5 per 1M in/out tokens - xai/grok-4.20-multi-agent-0309 — Grok 4.20 (multi-agent), 1,000,000 ctx, $1.25/$2.5 per 1M in/out tokens - xai/grok-build-0.1 — Grok Build 0.1, 256,000 ctx, $1/$2 per 1M in/out tokens - meta/llama-3.3-70b — Llama 3.3 70B Instruct, 128,000 ctx, $0.71/$0.71 per 1M in/out tokens - mistral/mistral-large-3 — Mistral Large 3, 128,000 ctx, $0.5/$1.5 per 1M in/out tokens - microsoft/phi-4 — Phi-4, 16,000 ctx, $0.125/$0.5 per 1M in/out tokens - deepseek/deepseek-v4-flash — DeepSeek V4 Flash, 1,000,000 ctx, $0.19/$0.51 per 1M in/out tokens - deepseek/deepseek-v4-pro — DeepSeek V4 Pro, 1,000,000 ctx, $1.74/$3.48 per 1M in/out tokens - deepseek/deepseek-v3-2 — DeepSeek V3.2, 163,840 ctx, $0.58/$1.68 per 1M in/out tokens - deepseek/deepseek-v3-2-speciale — DeepSeek V3.2 Speciale, 163,840 ctx, $0.58/$1.68 per 1M in/out tokens - zai/glm-5.2 — GLM-5.2, 1,000,000 ctx, $1.4/$4.4 per 1M in/out tokens - zai/glm-5.1 — GLM-5.1, 200,000 ctx, $1.4/$4.4 per 1M in/out tokens - zai/glm-5 — GLM-5, 200,000 ctx, $1/$3.2 per 1M in/out tokens - zai/glm-5-turbo — GLM-5 Turbo, 200,000 ctx, $1.2/$4 per 1M in/out tokens - zai/glm-4.7 — GLM-4.7, 200,000 ctx, $0.6/$2.2 per 1M in/out tokens - zai/glm-4.6 — GLM-4.6, 200,000 ctx, $0.6/$2.2 per 1M in/out tokens - zai/glm-4.5 — GLM-4.5, 128,000 ctx, $0.6/$2.2 per 1M in/out tokens - zai/glm-4.5-air — GLM-4.5 Air, 128,000 ctx, $0.2/$1.1 per 1M in/out tokens - cerebras/gpt-oss-120b — Cerebras GPT OSS 120B, 128,000 ctx, $0.35/$0.75 per 1M in/out tokens - cerebras/zai-glm-4.7 — Cerebras Z.ai GLM 4.7, 128,000 ctx, $2.25/$2.75 per 1M in/out tokens - cerebras/gemma-4-31b — Cerebras Gemma 4 31B, 128,000 ctx, $0.99/$1.49 per 1M in/out tokens - groq/gpt-oss-120b — Groq GPT OSS 120B, 128,000 ctx, $0.15/$0.6 per 1M in/out tokens - groq/gpt-oss-20b — Groq GPT OSS 20B, 128,000 ctx, $0.075/$0.3 per 1M in/out tokens - groq/llama-4-scout-17b-16e — Groq Llama 4 Scout (17Bx16E), 128,000 ctx, $0.11/$0.34 per 1M in/out tokens - groq/qwen3-32b — Groq Qwen3 32B, 131,000 ctx, $0.29/$0.59 per 1M in/out tokens - groq/llama-3.3-70b-versatile — Groq Llama 3.3 70B Versatile, 128,000 ctx, $0.59/$0.79 per 1M in/out tokens - groq/llama-3.1-8b-instant — Groq Llama 3.1 8B Instant, 128,000 ctx, $0.05/$0.08 per 1M in/out tokens - fireworks/glm-5.2 — Fireworks GLM 5.2, 1,040,000 ctx, $1.4/$4.4 per 1M in/out tokens - fireworks/glm-5.2-fast — Fireworks GLM 5.2 Fast, 1,040,000 ctx, $2.1/$6.6 per 1M in/out tokens - fireworks/gpt-oss-120b — Fireworks GPT OSS 120B, 128,000 ctx, $0.15/$0.6 per 1M in/out tokens - fireworks/gpt-oss-20b — Fireworks GPT OSS 20B, 128,000 ctx, $0.07/$0.3 per 1M in/out tokens - thinkingmachines/inkling — Inkling, 65,536 ctx, $1.87/$4.68 per 1M in/out tokens - thinkingmachines/inkling-256k — Inkling 256K, 262,144 ctx, $3.74/$9.36 per 1M in/out tokens