LLM API Comparison 2026

Choosing the right LLM API depends on your use case, budget, and technical requirements. This guide compares the major models—Claude, GPT-5, DeepSeek V4, and Gemini—across the dimensions that matter most.

Quick Comparison Table

Model	Provider	Context	Input Price	Output Price	Best For
claude-sonnet-4-6	Anthropic	200K	$3.00/M	$15.00/M	Coding, analysis, writing
claude-opus-4-8	Anthropic	200K	$15.00/M	$75.00/M	Complex research
claude-haiku-4-5	Anthropic	200K	$0.80/M	$4.00/M	Fast, cheap tasks
gpt-5	OpenAI	128K	$15.00/M	$60.00/M	Advanced reasoning
gpt-4o	OpenAI	128K	$5.00/M	$15.00/M	Multimodal
gpt-4o-mini	OpenAI	128K	$0.15/M	$0.60/M	Budget tasks
deepseek-v4	DeepSeek	128K	$0.27/M	$1.10/M	Cost-efficient coding
deepseek-r1	DeepSeek	64K	$0.55/M	$2.19/M	Reasoning, math
gemini-2.5-pro	Google	1M+	$1.25/M	$10.00/M	Ultra-long context
o3	OpenAI	200K	$10.00/M	$40.00/M	STEM reasoning

All prices at official list rates. APIMaster typically offers 30–70% off—see marketplace.

Detailed Model Comparisons

Coding and Development

Winner: DeepSeek V4 for cost-sensitive work; Claude Sonnet 4.6 for quality + context

Model	Code Quality	Price	Context
DeepSeek V4	Excellent	★★★★★ (cheapest)	128K
Claude Sonnet 4.6	Excellent	★★★	200K
GPT-5	Excellent	★ (most expensive)	128K
GPT-4o	Very Good	★★★	128K

DeepSeek V4 performs comparably to GPT-4o on coding benchmarks (HumanEval, MBPP) at ~20× lower cost.

Long-Context Document Analysis

Winner: Gemini 2.5 Pro (1M+ context); Claude Sonnet for 200K

Model	Max Context	Price for 200K Input
Gemini 2.5 Pro	1M+	~$0.25
Claude Sonnet 4.6	200K	~$0.60
Claude Opus 4.8	200K	~$3.00
GPT-5	128K	~$1.92

For documents exceeding 128K tokens, Claude and Gemini are the only options.

Reasoning and Math

Winner: o3 (best accuracy); DeepSeek R1 (best price)

Model	MATH Score	AIME 2024	Cost Index
o3	~97%	Top tier	High
DeepSeek R1	~97%	Near o1 level	Low
o4-mini	~95%	Strong	Medium
Claude Opus	~90%	Good	High

For math and formal reasoning, o3 and DeepSeek R1 are class leaders. R1 is typically 5–8× cheaper.

Creative Writing

Winner: Claude (any tier)

Claude models are consistently preferred for nuanced creative writing, character voice, and long-form narrative. GPT-5 is competitive but Claude's prose style is often preferred for literary tasks.

Multimodal (Vision + Text)

Winner: GPT-4o for versatility; Gemini for volume

Model	Image Input	Video	Audio
GPT-4o	✅	❌	✅
GPT-5	✅	❌	✅
Gemini 2.5 Pro	✅	✅	✅
Claude Sonnet 4.6	✅	❌	❌
DeepSeek V4	❌	❌	❌

Cost Optimization Decision Tree

Is cost the primary constraint?
├── Yes → DeepSeek V4 (coding/analysis) or GPT-4o mini (general)
└── No → Continue...

Do you need vision/multimodal?
├── Yes → GPT-4o or Gemini 2.5 Pro
└── No → Continue...

Do you need 200K+ context?
├── Yes → Claude Sonnet 4.6 or Gemini 2.5 Pro
└── No → Continue...

Is it a reasoning/math task?
├── Yes → o3 (quality) or DeepSeek R1 (cost)
└── No → Claude Sonnet 4.6 or GPT-4o

Accessing All Models Through One API

Rather than managing separate API keys for each provider, APIMaster provides a single OpenAI-compatible endpoint for all major models:

from openai import OpenAI

client = OpenAI(
    api_key="YOUR_APIMASTER_KEY",
    base_url="https://apimaster.ai/v1",
)

# Switch between any model with one line
for model in ["claude-sonnet-4-6", "gpt-4o", "deepseek-v4"]:
    resp = client.chat.completions.create(
        model=model,
        messages=[{"role": "user", "content": "Summarize the history of neural networks in 3 sentences."}],
        max_tokens=150,
    )
    print(f"\n{model}:\n{resp.choices[0].message.content}")

All models on APIMaster are fingerprint-verified—you know you're getting the model you paid for.

Compare live prices → · Get API access →