Criterion OpenAI API OpenRouter
CategoryLLM APIs & Model PlatformsLLM APIs & Model Platforms
In one sentencePay-per-token developer access to OpenAI's GPT models for building apps, agents and automations.One OpenAI-compatible API key for hundreds of models from many providers.
Problem it solvesAdding language understanding, generation and reasoning to a product without training or hosting a model yourself.Managing separate accounts, keys and SDKs for every model provider, and coping with provider outages.
Free planNoYes
Developer APIYes — docsYes — docs
Open sourceNoNo
PlatformsWeb (platform dashboard), REST APIWeb, REST API
Pricing (summary)Usage-based billing per 1M tokens, with separate rates for input, cached input and output. GPT-6 Astra costs $10 input / $50 output, GPT-6.1 Sol $2 / $10 and GPT-6 Luna $0.10 / $0.50 per 1M tokens on the Standard tier. Batch and Flex are about half price; Fast mode costs more.
Checked 2026-10-19		No subscription: inference is billed at each provider's list price, with a platform fee of 5.5% (Standard) or 8% (Business) on credit purchases. A free plan offers 25+ free models with request caps; Enterprise is contract-based.
Checked 2026-10-19
Strengths
  • Clear model tiers with published per-token prices
  • Very large context window on current models
  • Multiple cost-saving modes (Batch, Flex, caching)
  • Huge model catalogue
  • Provider list prices passed through
  • Free tier for testing
Limitations
  • No documented free API tier for the GPT models
  • Costs can grow quickly at the top tier ($50 per 1M output tokens for Astra)
  • Higher pricing applies above 272K input tokens per the pricing page tables
  • 5.5% (Standard) or 8% (Business) fee on credit purchases
  • Free model caps are low
  • Another intermediary in the data path