Best LLM API for Chatbots
Find the best LLM API for chatbots and conversational AI. Models ranked by human conversation preference (LMArena Elo), with verified pricing for dialogue, customer support, and interactive assistants.
MODELPRICEWATCH.COM · 2026-08-09
Cost calculator for this use casemonthly cost, top 3 models
- 1 GPT-5.5 Pro
- $—
- 2 Claude Fable 5
- $—
- 3 Claude Opus 4.6
- $—
Full ranking — top 23 models
list prices, USD per 1M tokens| Model | LMArena Elo | Blended* | Input | Output | Context | Provider |
|---|---|---|---|---|---|---|
| 1GPT-5.5 Pro | 1510 Elo | $67.50 | $30.00 | $180.00 | 1M | OpenAI |
| 2Claude Fable 5 | 1507 Elo | $20.00 | $10.00 | $50.00 | 1M | Anthropic |
| 3Claude Opus 4.6 | 1498 Elo | $10.00 | $5.00 | $25.00 | 1M | Anthropic |
| 4Qwen3.8-Max | 1497 Elo | $3.00 | $2.00 | $6.00 | 1M | Alibaba |
| 5Claude Opus 4.7 | 1493 Elo | $10.00 | $5.00 | $25.00 | 1M | Anthropic |
| 6Muse Spark 1.1 | 1488 Elo | $2.00 | $1.25 | $4.25 | 1M | Meta |
| 7Gemini 3.1 Pro | 1487 Elo | $4.50 | $2.00 | $12.00 | 2M | |
| 8Kimi K3 | 1485 Elo | $6.00 | $3.00 | $15.00 | 1M | Moonshot |
| 9Gemini 3.6 Flash | 1485 Elo | $3.00 | $1.50 | $7.50 | 1M | |
| 10GPT-5.6 Sol | 1482 Elo | $11.25 | $5.00 | $30.00 | 1M | OpenAI |
| 11GPT-5.4 Pro | 1478 Elo | $67.50 | $30.00 | $180.00 | 1M | OpenAI |
| 12GPT-5.5 | 1477 Elo | $11.25 | $5.00 | $30.00 | 1M | OpenAI |
| 13Gemini 3.5 Flash | 1476 Elo | $3.38 | $1.50 | $9.00 | 1M | |
| 14GPT-5.2 Chat | 1476 Elo | $4.81 | $1.75 | $14.00 | 128K | OpenAI |
| 15Grok 4.20 | 1475 Elo | $1.56 | $1.25 | $2.50 | 256K | xAI |
| 16Claude Opus 4.8 | 1473 Elo | $10.00 | $5.00 | $25.00 | 1M | Anthropic |
| 17Claude Sonnet 4.6 | 1472 Elo | $6.00 | $3.00 | $15.00 | 1M | Anthropic |
| 18GLM-5.2 | 1469 Elo | $2.15 | $1.40 | $4.40 | 1M | Z.AI |
| 19Grok 4.5 | 1468 Elo | $3.00 | $2.00 | $6.00 | 500K | xAI |
| 20GLM-5.1 | 1468 Elo | $2.15 | $1.40 | $4.40 | 128K | Z.AI |
| 21Inkling | 1442 Elo | $1.76 | $1.00 | $4.05 | 262K | Thinking Machines |
| 22Muse Spark 1.2 | — | $2.00 | $1.25 | $4.25 | 1M | Meta |
| 23Claude Opus 5 | — | $10.00 | $5.00 | $25.00 | 1M | Anthropic |
How models are selected
Generally-available conversational models (mid-tier, flagship and fast classes), ranked by LMArena Elo — blind human preference votes on real conversations, independently collected. One row per model — host duplicates are collapsed. Models without an Elo rating rank below rated ones, cheapest first.
Prices are per million tokens (Mtok), sourced directly from — and linked to — official provider pricing pages. "Blended cost" is (3×input + 1×output) ÷ 4 — weighted toward input because real workloads read far more tokens than they generate.