Best forBest first test for classification, structured extraction, support, routing, summaries, and narrow subagent steps.
Per 1M tokens · base list tier
Claude Haiku 5.5 and Claude Sonnet 5.5 both offer a 1-million-token context window, up to 128,000 output tokens, text-and-image input, and adaptive thinking. Their roles differ. Anthropic positions Haiku for high-volume, latency-sensitive work such as classification, extraction, and routing. Sonnet is the stronger starting candidate for coding, analysis, and agent workflows that need more sustained judgment. You can test both through the GPTProto API or Playground.
The short answer: start with Haiku 5.5 for frequent, checkable requests. Trial Sonnet 5.5 when coding or multi-step work needs a higher success rate. Pay special attention to prompt length: Anthropic applies a higher direct-API price tier above 100,000 input tokens. Confirm GPTProto billing for long requests rather than assuming the displayed base rate applies at every prompt length.
Best forBest first test for classification, structured extraction, support, routing, summaries, and narrow subagent steps.
Per 1M tokens · base list tier
Best forBest first test for defined coding tasks, code review, document analysis, and agent steps that need more reasoning.
Per 1M tokens · base list tier
The rates below are the base input and output prices displayed from the GPTProto catalog, checked on October 13, 2026. Anthropic publishes a separate prompt-length tier for Haiku above 100,000 input tokens. Confirm the applicable GPTProto billing for long requests; the displayed base price alone does not establish every tier.
curl https://gptproto.com/v1/chat/completions \
-H "Authorization: Bearer $GPTPROTO_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "claude-haiku-5-5",
"messages": [{"role": "user", "content": "Hi"}]
}'curl https://gptproto.com/v1/chat/completions \
-H "Authorization: Bearer $GPTPROTO_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "claude-sonnet-5-5",
"messages": [{"role": "user", "content": "Hi"}]
}'Prices per 1M tokens. Official list rates from Anthropic via the GPTProto catalog (raw price / 740). GPTProto rates apply price_multiplication 0.9. Latency and benchmarks are OpenRouter figures as of 2026-10-14.
GPTProto’s catalog lists Haiku 5.5 at $0.09 input and $0.45 output per million tokens, versus Sonnet 5.5 at $1.80 input and $9.00 output. These are displayed base rates; confirm the applicable tier for the prompt size you plan to send. On those displayed rates, Sonnet costs 20 times as much per input or output token. A 10,000-input-token, 1,000-output-token request would cost about $0.00135 on Haiku or $0.027 on Sonnet at those rates, before cache and other charges.
Long prompts need a separate cost check. Anthropic’s direct API changes Haiku’s input/output rates from $0.10/$0.50 to $0.50/$2.50 per million tokens when a request exceeds 100,000 input tokens; the higher tier applies to the full request. The GPTProto catalog stores that official tier and a 0.9 multiplier, which converts to $0.45 input and $2.25 output. Those catalog figures are not a promise about every long-prompt invoice. The threshold concerns each request’s prompt length, not the monthly token total.
Review the current Haiku 5.5 model price, Sonnet 5.5 model price, and GPTProto’s Haiku long-prompt comparison.
Estimate costs from your expected input and output tokens, separating requests at or below 100K input tokens from those above it and confirming the applicable GPTProto rates for each group. Add cache use, retries, tool calls, and the number of attempts each model needs to pass your acceptance test.
Excludes top-up bonus credits. Haiku 5.5 is priced here at its ≤100K-token prompt tier. Assumes flat usage at the published per-1M-token rate.
Anthropic labels Haiku 5.5 Fastest and Sonnet 5.5 Fast relative to its model lineup. Neither label promises a specific GPTProto latency. Prompt length, thinking effort, tool calls, and output size can change the end-to-end time. Test both through the live model pages with the same request and settings.
OpenRouter figures as of 2026-10-14. “Fastest” and “Fast” are Anthropic’s relative classifications. Not a GPTProto SLA.
Use one GPTProto account and balance to test Haiku and Sonnet at their displayed rates. A practical application can put repeatable requests on Haiku and reserve Sonnet for tasks that fail validation or require more reasoning. Keep the routing rule visible in your usage data so a cheaper first call does not hide the cost of repeated escalations.
Get started. Great for testing the endpoint and trying new models.
The sweet spot for individual developers and small projects shipping to production.
Built for teams running production workloads. Bonus credits stack on already-discounted model pricing.
Haiku 5.5 fits labeling tickets, extracting fields, routing requests, concise summaries, and focused coding subagent work. Sonnet 5.5 is the more relevant candidate for repository changes, code review, longer document analysis, and multi-step agent work. A published score does not mean one model wins every prompt.
Artificial Analysis, Vals AI, and Design Arena figures as listed on OpenRouter, 2026-10-14.
Pick by the check you can run — not by which release is newer.
Give narrow, verifiable subtasks to Haiku and escalate ambiguous or failed steps to Sonnet. Preserve the instructions, evidence, and acceptance test when handing off. Count both calls in the final cost per completed task; a routing strategy only helps if it improves the outcome or the bill.
Anthropic specifies text and image input, text output, a 1M-token context window, and a standard 128K-token output limit for both models. Thinking tokens count toward the output budget, and the selected GPTProto route may impose its own request limits. Haiku’s upstream 100K pricing threshold means matching context capacity does not imply a flat rate at every prompt length. Split documents into useful evidence only when doing so preserves the facts needed to answer; do not truncate a task solely to fit a cheap tier.
For document workflows, GPTProto has Haiku file-analysis and Sonnet file-analysis pages. It also has model-specific Haiku web-search and Sonnet web-search routes; check the live request schema before deploying.
Build an evaluation set from your actual workload: routine cases, difficult failures, and long prompts on both sides of the 100K threshold. Run both models with comparable instructions, tools, and reasoning settings. Score accepted outcomes, retries, latency, and total tokens. Report the share of requests that need escalation and the resulting cost per completed task. A single average can hide both Haiku’s high-volume advantage and Sonnet’s value on harder work.
Both model pages include a Playground, API examples, and current pricing. Check the rate for your prompt length, run representative requests, and choose the default—or escalation rule—that meets your quality, speed, and budget requirements. Browse Claude models on GPTProto.
Yes at the displayed base rates checked on October 13, 2026: Haiku is $0.09 input / $0.45 output and Sonnet is $1.80 / $9.00 per million tokens. Anthropic has a higher direct-API Haiku tier above 100K input tokens. The catalog converts that official tier with the same 0.9 multiplier, but confirm the applicable GPTProto rate and prompt length before budgeting.
Anthropic classifies Haiku as Fastest and Sonnet as Fast relative to its other models. Those are not GPTProto latency measurements. On OpenRouter’s provider medians checked October 14, 2026, Haiku’s p50 latency was 1.49 s and Sonnet’s was 1.91 s. Benchmark both with your own prompt lengths, thinking settings, and output sizes.
Try Haiku on narrow, checkable coding substeps. Trial Sonnet for defined bug fixes, code review, and changes requiring more reasoning across files. Use tests, retry counts, and cost per accepted patch to decide.
No. Anthropic lists a 1M-token context window and a standard 128K-token maximum output for both. Haiku’s prompt-length price threshold is a billing distinction, not a smaller context limit.
Yes. Anthropic lists adaptive thinking and text-and-image input with text output for both. OpenRouter lists Haiku reasoning as optional and Sonnet reasoning as mandatory, with adjustable effort on both. Image input is for understanding images, not generating them.
Yes. The catalog includes Claude Haiku 5.5 and Claude Sonnet 5.5 model pages with pricing, API examples, and a Playground. The Claude catalog shows the current lineup.
Creators and developers share the models and workflows they built with.
For a team already juggling DeepSeek, Kimi, Qwen, or other providers, a shared routing layer can be reasonable if it removes duplicated work and the fallback behavior is tested. GPTProto is one implementation of this approach.

I've been testing GPTProto recently, and it's honestly made my creative workflow much simpler. Instead of paying for multiple subscriptions, I can access several leading AI models from one place.

I turned this single prompt into a cinematic fantasy video using GPTProto. "Continuous 15-second cinematic shot, 4K resolution, hyper-realistic dark fantasy photorealism…"

I challenged myself to create a cinematic AI cooking short in just 15 seconds. I used GPTProto to bring the entire workflow together, from image generation to video, all in one place.

Made with Seedance 2.0 + GPT Image 2 on GPTProto. A Pixar-style commercial with the perfect glow.
What worked for me was pointing the cloud connections at GPTProto so the frontend only sees one endpoint and I just change the model name to swap. I am not rebuilding a connection from scratch every time.
I route the calls through GPTProto so a fallback is a config switch instead of a weekend rewrite when a model disappears. It turns "my default model just got export controlled" from an incident into a config change.

I used to switch between different AI tools just to compare results. Now I just use GPTProto. GPT-5, Claude, Gemini, Kimi, and more — all in one workspace.
I route the calls through GPTProto so the model id and latency land in one place regardless of which provider is behind it. The win is having the log schema consistent across providers.

I created this 15-second cinematic product video with GPTProto using Seedance 2.0, and I was really impressed by how smooth the workflow was.

GPTProto routes the character prompt and shot list to a top model on one API key: 20 minutes … voices it and burns in captions from the same key: 20 minutes.
Text, images, and voice are configured separately. You can keep OpenRouter for text and use GPTProto for visuals.
The call layer underneath the router is GPTProto, so swapping a model does not require provisioning a new provider integration. Changing models becomes cheap enough that the question stops being "should we change."
Compare models, learn API setup, and explore image and video workflows for real projects.
Create images and videos online, or bring text, image, and video models into your app with one API key. Explore discounted rates on selected models.