Chatbot · 10k users · 5/day · 400/600 tokens

OpenAI API

Rate-limit-bound
Rate-limit bound — the provider tier caps you at 100k users users before you need to upgrade or split keys.
Cost / month$10.5kat 10k users
Cost / request$0.00701.5M req/mo
Cost / user$1.05monthly
Cost / year$126.0kconstant traffic

Cost over time

$0$288.8k$577.5k$866.3k$1.2M1k5k10k25k50k100k250k500k1M1kMonthly active usersOpenAI API

Cost composition at 10k users

LLM tokens$10.5k100%

Latency breakdown

p50 end-to-endInfinitys
LLM generationInfinitys · NaN%

Generation scales linearly with output tokens — shrink the response or pick a higher-throughput model to bring this down.

Breaking points

  • Total response exceeds 8.0s (Infinitys) — past what chatbot users tolerate
    Drop output tokens, switch to a higher-throughput model (Cerebras ~800 tok/s, Groq ~500 tok/s, Gemini Flash ~120 tok/s), or stream the response so users see progress.
  • Cost crosses $1,000/mo at 1k users
    Move to a cheaper model, enable prompt caching, or send non-real-time traffic via the batch API.
  • Cost crosses $5,000/mo at 5k users
    Move to a cheaper model, enable prompt caching, or send non-real-time traffic via the batch API.
  • Cost crosses $20,000/mo at 25k users
    Move to a cheaper model, enable prompt caching, or send non-real-time traffic via the batch API.
  • Cost crosses $100,000/mo at 100k users
    Move to a cheaper model, enable prompt caching, or send non-real-time traffic via the batch API.
  • Peak load exceeds provider rate limit at 100k users (3× peak/avg)
    Move to a higher provider tier, distribute across multiple API keys, or buffer non-real-time traffic via batch API.

Provider comparison

Same workload at 10k users — ranked by monthly cost. Click a row to switch primary LLM.

ModelCost / moCost / reqp50 latency
DeepInfraCheapest$5700.038¢12.35s
Groq$1.1k0.071¢12.10s
DeepSeek API$1.2k0.077¢6.11s
Fireworks AI$1.4k0.090¢12.20s
Together AI$1.4k0.090¢12.25s
Perplexity API$1.5k$0.001012.50s
Cerebras$1.6k$0.001112.05s
Z.AI GLM API$4.8k$0.003212.60s
Google Gemini API$5.3k$0.0035Infinitys
Mistral API$6.6k$0.00449.87s
xAI Grok API$10.2k$0.00687.56s
Cohere API$10.5k$0.007011.02s
Azure OpenAI$10.5k$0.007012.60s
OpenAI APICurrent$10.5k$0.0070Infinitys
Amazon Bedrock$15.3k$0.01012.60s
Anthropic API$15.3k$0.010Infinitys

Structural risks

Switch away from this stack when

  • Monthly users exceed 1k (p50 latency above 2s).
  • Peak load exceeds the LLM provider's standard tier (around 100k).

Structural risks

  • No eval layer in stack. Add Langfuse, Braintrust, or DeepEval to catch quality regressions before users do.