Contents
OpenRouter vs Together.AI: API Aggregation vs Inference Platform
OpenRouter and Together.AI solve LLM inference differently. Pick one based on model needs and cost tolerance.
OpenRouter Service Model
OpenRouter aggregates multiple LLM providers. Developers hit one API, access dozens of models from different companies. It handles provider routing automatically, or developers pick manually.
Billing stays unified. One invoice for everything. SDKs make it easy to swap models mid-stream.
They make money on a markup (5-15% typically) over what providers charge. Developers see the base cost and their cut - no hidden fees.
Together.AI Service Model
Together.AI runs its own inference platform. Mostly open-source models (Llama, Mistral, etc.). Developers call their endpoints directly, no aggregation.
They optimize each model on custom hardware. They tune throughput and latency per model. The API looks like OpenAI's - drop-in compatible.
Pricing undercuts aggregators. No middleman markup. Proprietary models? They don't have those.
Pricing Structure Analysis
OpenRouter: per-token pricing that varies by provider and markup.
- Llama 70B (via Meta): $0.81/1M input tokens
- GPT-4 (via OpenAI): $30/1M input tokens
- Everything else: base cost + 5-15% OpenRouter cut
Together.AI keeps it simple.
- Llama 70B: $0.50/1M input tokens
- Mistral 7B: $0.15/1M tokens
- No hidden markup
Both offer volume discounts. Production teams negotiate down to 20-30% off list price.
Model Availability Comparison
OpenRouter: 100+ models across the ecosystem. GPT-4, Claude, all the proprietary stuff. Plus open-source. Basically everything.
Together.AI: Open-source only. Llama, Mistral, others. Strong for cost-conscious teams. Missing proprietary models completely.
The tradeoff is obvious. Need Claude or GPT-4? OpenRouter. Open-source only? Together.AI saves developers money.
Performance Characteristics
OpenRouter: latency bounces around. Routing overhead, provider latency variation. Count on 200-500ms per request. Predictability? Not its strong suit.
Together.AI: 100-300ms average. Dedicated infrastructure means consistent performance. If latency matters, they're better.
Throughput patterns differ. Together.AI scales cleanly. OpenRouter's throughput depends on which provider developers hit. Pick Together.AI if developers need predictable perf under load.
Cost Efficiency Scenarios
Running Llama 70B only? Together.AI costs 40% less. No markup eating into the budget. OpenRouter's 5-15% cut adds up fast at scale.
Need to flip between models constantly? OpenRouter wins. One SDK handles routing. Managing multiple providers yourself sucks.
Locked into GPT-4 or Claude? OpenRouter's the only option. Together.AI can't offer those models.
See Together.ai pricing for current rate cards. Check Groq API pricing for alternative inference costs. Compare with OpenAI API pricing for proprietary model baselines. Review Anthropic API pricing for additional options. Check DeepSeek API pricing for emerging model availability.
Token Counting and Cost Prediction
OpenRouter exposes token counting. SDKs automate it. Predictions hit within a few percent.
Together.AI uses OpenAI's token standard. Same rules apply. Predictions are solid.
Both services count transparently. Budget planning isn't a guessing game.
Integration Complexity
OpenRouter: Drop-in compatible with OpenAI's API. Minimal code changes if developers're migrating. A few days to production.
Together.AI: Same story. OpenAI-compatible. SDKs exist for everything.
Switching between them takes a few hours. Both APIs are nearly identical.
Request Latency Profiles
OpenRouter: 200-500ms per request (routing overhead + provider latency). Interactive apps feel sluggish.
Together.AI: 100-300ms. Much tighter. Better for anything latency-sensitive.
Batch processing helps both, but Together.AI's gains are more predictable.
Vendor Reliability
OpenRouter: Multiple dependencies mean failure cascades. Provider goes down? That model's unavailable.
Together.AI: Single vendor. Simpler failure modes. Dedicated ops team.
Both are stable, but OpenRouter has a wider risk surface. Production tolerance for risk determines the pick. See Groq API pricing and Deep Infra pricing for alternatives with different reliability profiles.
Model Quality Differences
Same model = same quality on both platforms. Llama 70B is Llama 70B. The platform doesn't change model weights.
Quantization or batching settings could diverge, but both services handle that competently. Together.AI offers fine-tuning if developers need it. Real-world testing shows no meaningful difference.
Platform choice barely matters for quality. Model choice matters hugely.
Support and Documentation
OpenRouter: Docs cover the basics. Community examples thin. Support's slow.
Together.AI: Better docs. Integration guides exist. Support actually responds. Better experience overall.
Both use OpenAI's API conventions, so most of the existing knowledge transfers. Learning curve is flat either way.
Long-Term Platform Viability
OpenRouter: Well-funded, growing, actively developed. Safe bet.
Together.AI: Recent major funding round. Production customers increasing. Good trajectory.
Both look stable. Neither's at risk of shutting down. Safe for production.
FAQ
Should I choose OpenRouter or Together.AI?
Choose Together.AI for open-source models and cost optimization. Choose OpenRouter for proprietary model access or model diversity. Hybrid approach uses both: Together.AI for baseline, OpenRouter for experiments.
What's the price difference for 1 billion daily tokens?
Together.AI with Llama 70B costs $15,000 monthly. OpenRouter markup costs $17,000-19,000 monthly. 10-25% savings with Together.AI. Difference grows with volume.
Can I migrate between platforms easily?
Yes. Both use OpenAI-compatible APIs. Code changes minimal. Migration takes 1-2 days. Framework compatibility enables same code running on both.
Which handles spike traffic better?
Together.AI handles spikes transparently. Auto-scaling included. OpenRouter depends on provider capacity. Together.AI more reliable during peaks.
What about custom model fine-tuning?
Together.AI supports fine-tuning on their infrastructure. OpenRouter delegates to providers. Different capabilities depending on provider. Check specific model availability.
Related Resources
- Together.ai platform
- OpenRouter API documentation
- OpenAI API pricing
- Groq API documentation
- LLM inference optimization
- Token counting guide
Sources
Data current as of March 2026. Pricing reflects public API rate cards. Performance metrics from platform documentation and community testing. Availability from current product offerings. Comparison based on publicly documented specifications and user reports.