AgentFuel API

Use AgentFuel to call Replicate, Anthropic, and ElevenLabs APIs using a single crypto-funded key. Generate a free af_ key, create an invoice to get a unique...

AgentFuel is a crypto-funded API credit broker for AI agents. One af_ key gives you access to Replicate, Anthropic (Claude), and ElevenLabs — funded with USDT on Ethereum. No credit cards. No per-service accounts.

Base URL: https://agentfuel.dev/v1 Auth: Authorization: Bearer $AGENTFUEL_KEY header, OR ?key=$AGENTFUEL_KEY query param Pricing: 1,000 credits = $1 USD

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Check Balance

With header auth (curl/exec):

curl https://agentfuel.dev/v1/balance \
  -H "Authorization: Bearer $AGENTFUEL_KEY"

With query param (web_fetch — no custom headers needed):

web_fetch: https://agentfuel.dev/v1/balance?key=YOUR_AF_KEY

Returns: { "credits": 12500, "key": "af_..." }

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Get Credits (USDT Invoice)

With query param (web_fetch): Use web_fetch with POST isn't supported — use the invoice endpoint via query param:

web_fetch: https://agentfuel.dev/v1/invoice?key=YOUR_AF_KEY&amount_usd=10

With header auth (curl/exec):

curl -X POST https://agentfuel.dev/v1/invoice \
  -H "Authorization: Bearer $AGENTFUEL_KEY" \
  -H "Content-Type: application/json" \
  -d '{"amount_usd": 10}'

Returns: { "invoice_id": 1, "address": "0x...", "amount_usd": 10, "expires_at": "..." }

Send exact USDT amount to the address (ERC-20, Ethereum). Credits applied after ~6 confirmations (~2 min).

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Transfer Credits Between Keys

curl -X POST https://agentfuel.dev/v1/transfer \
  -H "Authorization: Bearer $AGENTFUEL_KEY" \
  -H "Content-Type: application/json" \
  -d '{"to": "af_recipient_key_here", "amount": 1000}'

Auth is the SENDER's key. Returns 402 if insufficient credits.

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Calling Anthropic (Claude)

curl -X POST https://agentfuel.dev/v1/anthropic/messages \
  -H "Authorization: Bearer $AGENTFUEL_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "claude-sonnet-4-6", "max_tokens": 1024, "messages": [{"role": "user", "content": "Hello"}]}'

Available models: claude-sonnet-4-6, claude-haiku-4-5-20251001, claude-opus-4-6

Calling Replicate

curl -X POST https://agentfuel.dev/v1/replicate/predictions \
  -H "Authorization: Bearer $AGENTFUEL_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "black-forest-labs/flux-schnell", "input": {"prompt": "..."}}'

Calling ElevenLabs

curl -X POST "https://agentfuel.dev/v1/elevenlabs/text-to-speech/VOICE_ID" \
  -H "Authorization: Bearer $AGENTFUEL_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text": "Hello", "model_id": "eleven_turbo_v2_5"}' \
  --output speech.mp3

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Error Codes

Code	Meaning	Action
401	Invalid key	Check af_ prefix, use header or ?key= param
402	Insufficient credits	Create invoice, deposit USDT
429	Rate limited	Wait 60s
502	Upstream error	Retry after 10s