Staxly

Anthropic API vs OpenAI API

API for Claude — frontier models for chat, tool use, agents, and long-context reasoning
vs. Frontier models: GPT-5, o-series reasoning, image, audio, embeddings

Anthropic website ↗OpenAI Platform ↗

Pricing tiers

Anthropic API

Opus 4.7 — usage
Input $5 / output $25 / cache-write $6.25 / cache-read $0.50 per 1M tokens. Batch = 50% off.
Custom
Sonnet 4.6 — usage
Input $3 / output $15 / cache-write $3.75 / cache-read $0.30 per 1M tokens. Batch = 50% off.
Custom
Haiku 4.5 — usage
Input $1 / output $5 / cache-write $1.25 / cache-read $0.10 per 1M tokens. Batch = 50% off.
Custom
Anthropic website ↗

OpenAI API

Free Tier (Trial)
$5 free credit for new accounts. Rate-limited.
Free
Pay-as-you-go
No monthly min. Per-token pricing by model.
$0 base (usage-based)
Usage Tiers (1-5)
Automatic tier promotion based on cumulative spend. Higher tiers = higher rate limits + new model access.
$0 base (usage-based)
Enterprise
Custom. Priority access, SLA, dedicated capacity.
Custom
OpenAI Platform ↗

Free-tier quotas head-to-head

Comparing opus-4-7 on Anthropic API vs free-tier on OpenAI API.

MetricAnthropic APIOpenAI API
discount batch50 % off—

Features

Anthropic API · 0 features

    OpenAI API · 12 features

    • Assistants API — Stateful assistants with tools, threads, file search.
    • Batch API — 50% discount for async processing within 24h.
    • Chat Completions API — Classic /v1/chat/completions endpoint.
    • Files API — Upload docs for retrieval, fine-tuning, batch.
    • Fine-Tuning — Supervised + DPO fine-tuning for GPT-4o, GPT-4.1, GPT-4o-mini.
    • Function Calling — JSON-schema tool calling; parallel calls supported.
    • Moderation — Safety classifier API (free).
    • Prompt Caching — Auto-cache repeated prefixes; 50% cheaper cached hits.
    • Realtime API — WebSocket streaming voice + text with low latency.
    • Responses API — Stateful conversational API.
    • Structured Outputs — Enforced JSON schema compliance.
    • Vision — Image input for GPT models.

    Developer interfaces

    KindAnthropic APIOpenAI API
    CLIClaude Code CLI—
    SDKGo SDK, Java SDK, Python SDK, Ruby SDK, TypeScript SDK (@anthropic-ai/sdk)openai-dotnet, openai-go, openai-node, openai-python
    RESTAWS Bedrock, Google Vertex AI, Microsoft Azure AI, REST API (Messages + Agents)OpenAI REST API
    MCP—OpenAI MCP
    OTHER—Realtime API (WebSocket)
    Staxly is an independent catalog of developer platforms. Outbound links to Anthropic API and OpenAI API are plain references to their official websites. Pricing is verified against vendor pages at publication time — reconfirm before buying.

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