Agentfuel API

AgentFuel API

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 header: Authorization: Bearer $AGENTFUEL_KEY Pricing: 1,000 credits = $1 USD

Startup: Get a Key and Check Balance

If you don't have an af_ key yet, generate one for free:

curl -X POST https://agentfuel.dev/v1/new-key \
  -H "Content-Type: application/json" \
  -d '{"label": "my-agent"}'

Response:

{
  "key": "af_abc123...",
  "credits": 0,
  "message": "Key created. Use POST /v1/invoice to get a deposit address and add credits."
}

Save your key. Then check your balance before making API calls:

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

Response:

{
  "credits_remaining": 500,
  "credits_used": 0,
  "credits_total": 500,
  "usd_value": "0.50",
  "usage_by_service": {
    "replicate": 0,
    "anthropic": 0,
    "elevenlabs": 0
  }
}

If credits_remaining is 0, create an invoice to deposit USDT.

How to Get Credits (USDT Invoice)

AgentFuel uses a secure invoice system. Each invoice gives you a unique deposit address — no need to submit transaction IDs. Credits are applied automatically after 6 confirmations (~2 minutes).

Step 1 — Create an invoice

During alpha, invoices are fixed at $5 USD (5,000 credits). Set amount_usd: 5.

curl -X POST https://agentfuel.dev/v1/invoice \
  -H "Authorization: Bearer $AGENTFUEL_KEY" \
  -H "Content-Type: application/json" \
  -d '{"amount_usd": 5}'

Response:

{
  "invoice_id": 42,
  "pay_to_address": "0xCc4343235BC4B3C1415DA4A106fdC55B3519fDe8",
  "network": "ERC-20 (Ethereum mainnet)",
  "token": "USDT",
  "amount_usdt": "5.00",
  "credits": 5000,
  "expires_at": "2026-01-01 12:30:00",
  "note": "Send exactly this amount of USDT to the address above. Credits are applied automatically after 6 confirmations (~2 min)."
}

Step 2 — Send USDT

Send exactly the amount_usdt of USDT (ERC-20, Ethereum mainnet) to pay_to_address. Each invoice has its own unique address — do not reuse addresses across invoices.

Invoice expires in 30 minutes.

Step 3 — Poll for confirmation

curl https://agentfuel.dev/v1/invoice/42 \
  -H "Authorization: Bearer $AGENTFUEL_KEY"

Response when paid:

{
  "invoice_id": 42,
  "status": "paid",
  "amount_usdt": 10,
  "credits": 10000,
  "paid_at": "2026-01-01 12:05:33",
  "sweep_txid": "0xabc..."
}

Poll every 30 seconds until status is "paid". Once paid, your balance increases immediately.

Calling Replicate

Route Replicate calls through /v1/replicate/. Same request format as api.replicate.com/v1/.

Submit a prediction

curl -X POST https://agentfuel.dev/v1/replicate/predictions \
  -H "Authorization: Bearer $AGENTFUEL_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "version": "MODEL_VERSION_HASH",
    "input": { }
  }'

Poll for result

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

Poll every 2–3 seconds until status is "succeeded". Credits are deducted on success.

FLUX Schnell (4 credits/run)

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": "a photorealistic cat sitting on a rooftop at sunset",
      "num_outputs": 1
    }
  }'

Calling Anthropic (Claude)

Route calls through /v1/anthropic/messages. Identical to api.anthropic.com/v1/messages.

Text message

curl -X POST https://agentfuel.dev/v1/anthropic/messages \
  -H "Authorization: Bearer $AGENTFUEL_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-haiku-4-5-20251001",
    "max_tokens": 1024,
    "messages": [{"role": "user", "content": "Your prompt here"}]
  }'

Vision (image analysis)

curl -X POST https://agentfuel.dev/v1/anthropic/messages \
  -H "Authorization: Bearer $AGENTFUEL_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-haiku-4-5-20251001",
    "max_tokens": 512,
    "messages": [{
      "role": "user",
      "content": [
        {"type": "image", "source": {"type": "url", "url": "https://example.com/image.jpg"}},
        {"type": "text", "text": "Describe this image."}
      ]
    }]
  }'

Calling ElevenLabs

Route calls through /v1/elevenlabs/. Returns audio/mpeg.

curl -X POST \
  "https://agentfuel.dev/v1/elevenlabs/text-to-speech/21m00Tcm4TlvDq8ikWAM" \
  -H "Authorization: Bearer $AGENTFUEL_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "text": "Your design is ready.",
    "model_id": "eleven_turbo_v2_5"
  }' \
  --output speech.mp3

Error Handling

On 402, the response includes credits_required, credits_available, and a next_step field with the exact action to take (create an invoice). Follow next_step to self-heal without human intervention.

Pricing Reference

1,000 credits = $1 USD

About AgentFuel

AI-native API access, funded by crypto. Visit agentfuel.dev. Skill hosted at: https://agentfuel.dev/skill.md