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Compare models

Put up to 4 models beside each other — token prices, context windows, capabilities and provider, from the same catalogue the model pages read.

  1. Universal-3.5 ProAssemblyAIRemove
  2. S1Fish AudioRemove
  3. S2.1 ProFish AudioRemove
  4. GPT-6 Sol ProOpenAIRemove

4 is the maximum. Remove one to add another.

universal-3-5-pro vs s1 vs s2.1-pro vs gpt-6-sol-pro
AttributeUniversal-3.5 Prouniversal-3-5-proS1s1S2.1 Pros2.1-proGPT-6 Sol Progpt-6-sol-pro
Pricing
Input$0 / 1M$0 / 1M$0 / 1M$2.00 / 1M
Output$0 / 1M$0 / 1M$0 / 1M$10.00 / 1M
Cache Write (5m)Not applicableNot applicableNot applicable$2.00 / 1M
Cache Write (1h)Not applicableNot applicableNot applicable$2.00 / 1M
Cache ReadNot applicableNot applicableNot applicable$2.00 / 1M
Web Search$0 / 1M$0 / 1M$0 / 1M$0 / 1M
Context
Max contextN/AN/AN/A1.1M
Max outputN/AN/AN/AN/A
Capabilities
VisionNoNoNoYes
Function CallingNoNoNoYes
JSON ModeNoNoNoYes
StreamingNoNoNoYes
Catalogue
ProviderAssemblyAIFish AudioFish AudioOpenAI
Categoryvoicevoicevoicechat
Charge typePay As You GoPay As You GoPay As You GoPay As You Go
Released2026-09-222026-07-292026-07-29—
Description
SummaryAssemblyAI Universal-3.5 Pro speech-to-text. Billed per second of audio.Fish Audio S1 text-to-speech. Billed per UTF-8 byte of input text.Fish Audio S2.1 Pro text-to-speech. Billed per UTF-8 byte of input text.GPT-6 Sol Pro uses the same underlying model as GPT-6 Sol, but runs with reasoning.mode set to pro for higher-quality responses on complex and demanding tasks. Optimized for deeper reasoning, greater accuracy, and more reliable multi-step execution, it is particularly well suited for agentic coding, long-horizon software engineering, professional analysis, and complex automated workflows where solution quality takes priority over latency and cost.