Text to speech and voice AI across every device
Text to speech and voice AI across every device
CastReader records 55,999 monthly visits with +9.8% month-over-month growth and Freemium pricing. OpenRouter records 19,941,437 monthly visits with -6.2% growth and Paid pricing.

Read aloud webpages, PDFs, Kindle books and AI answers with synced highlighting
| Dimension / Metric | ![]() | |
|---|---|---|
| Official Domain | castreader.com | openrouter.ai |
| Pricing Model | Freemium | Paid |
| Monthly Visits | 56K (55,999) | 19.94M (19,941,437) |
| MoM Traffic Delta | +4.98K (+9.8%) | -1.33M (-6.2%) |
| Primary Market & Share | 🇺🇸 United States (56%) | 🇺🇸 United States (16.1%) |
| Direct Visits / mo | 19.7K | 11.96M |
| User Rating | 4.4 | 4.8 |
| Supported Platforms | Website | Website |

Read aloud webpages, PDFs, Kindle books and AI answers with synced highlighting
Natural AI voices narrate webpages, PDFs, ebooks and documents while each spoken word is highlighted and the page auto-scrolls, so you never lose your place.
Instead of only reading a hard passage, CastReader summarises and unpacks its meaning in the language you know best, with an animated pen marking the key lines in the original text.
Works across Kindle, WeRead, Google Play Books, O'Reilly and other book platforms, news and newsletter sites, Google Docs, Notion, Gmail, plus ChatGPT, Claude, Gemini, DeepSeek and Kimi answers.
Preview real samples of dozens of voices across many languages, and create private cloned voices that Pro members can apply to their own PDF, EPUB, Word and TXT files.
One API key for hundreds of AI models from every major provider
Six hundred plus models for text, image, video, audio, transcription, embeddings, and reranking behind one OpenAI-compatible API.
Requests are rerouted to another provider on outages or rate limits by default, so you don't write custom retry logic.
The auto-router selects a model and provider per request using live marketplace performance and pricing data.
Track spend, tokens, and usage per model, provider, and team member in one place, including bring-your-own-key usage.
Text to speech and voice AI across every device
Text to speech and voice AI across every device

Offers robust serverless inference and GPU clusters for open models, but features a narrower selection of proprietary models.
Offers robust serverless inference and GPU clusters for open models, but features a narrower selection of proprietary models.
Free AI text to speech with 200+ voices in 70+ languages
Free AI text to speech with 200+ voices in 70+ languages
Features adaptive LLM routing and automatic failover, but lacks OpenRouter's massive ecosystem of community-rated model endpoints.
Features adaptive LLM routing and automatic failover, but lacks OpenRouter's massive ecosystem of community-rated model endpoints.
SpecialistDelivers exceptional inference speed and high-throughput performance for open models, but focuses primarily on hosted weights rather than multi-provider aggregation.

Free / Open-sourceProvides self-hosted and Python SDK control over 100+ LLMs, but requires setting up your own infrastructure.

SpecialistLow-cost serverless inference APIs for 200+ open models

One unified API for 100+ AI models, with insurance when output disappoints
One unified API for 100+ AI models, with insurance when output disappoints
Listen to anything. Beautifully.
Listen to anything. Beautifully.
One API for fast, cost-predictable inference on LLMs and multimodal models
One API for fast, cost-predictable inference on LLMs and multimodal models

Aggregates hundreds of foundation models and agentic tools under one endpoint, but lacks OpenRouter's community popularity and extensive prompt tuning.
Delivers advanced enterprise observability, guardrails, and caching, but focuses more on governance than simple model aggregation.
Delivers advanced enterprise observability, guardrails, and caching, but focuses more on governance than simple model aggregation.