anthropic/claude-opus-5-5
estimated usage cost
$14.00
1,000 requests × (1,000 uncached input × $4.00 + 500 output × $20.00) / 1,000,000 = $14.00
base rates; no context pricing tiers are published.
Claude Opus 5.5 vs GPT-5.3 Codex
rates, context and capabilities side by side on the impossibl api, and what the same workload costs on each.
| specification | Claude Opus 5.5 anthropic/claude-opus-5-5 | GPT-5.3 Codex openai/gpt-5.3-codex |
|---|---|---|
| input · usd / 1m tok | $4.00 | $1.75 |
| output · usd / 1m tok | $20.00 | $14.00 |
| context window | 1mtokens | 400ktokens |
| modalities · in → out | takes text and image in, gives text out | takes text and image in, gives text out |
pricing
| base api rates · usd per 1m tokens | Claude Opus 5.5 anthropic/claude-opus-5-5 | GPT-5.3 Codex openai/gpt-5.3-codex |
|---|---|---|
| input | $4.00 | $1.75 |
| output | $20.00 | $14.00 |
| cache read | $0.20 | $0.175 |
| cache write · default ttl | $5.00 | not published |
| cache write · 1h ttl | $8.00 | not published |
the estimate below prices one workload at these rates on every model.
specifications
| as published | Claude Opus 5.5 anthropic/claude-opus-5-5 | GPT-5.3 Codex openai/gpt-5.3-codex |
|---|---|---|
| creator | Anthropic | OpenAI |
| model type | Text generation | Text generation |
| context window | 1,000,000tokens | 400,000tokens |
| input | takes text and image in, gives text out | takes text and image in, gives text out |
| output | text | text |
| tool calling | not verified | not verified |
| released | sep 22, 2026 | feb 5, 2026 |
| endpoint | /v1/chat/completions | /v1/chat/completions |
unknown means the public catalog does not establish that fact. a model's documented capabilities can differ from what a particular api supports. see the model documentation for integration details.
benchmarks
| primary configuration | Claude Opus 5.5 anthropic/claude-opus-5-5 no benchmarks yet | GPT-5.3 Codex openai/gpt-5.3-codex xhigh |
|---|---|---|
| intelligence index · gateway rank | not measured | 32.5#32 of 90 |
| omniscience | not measured | 10.9#23 of 86 |
| gpqa | not measured | 91.5%#26 of 88 |
| humanity’s last exam | not measured | 42.5%#19 of 89 |
| tau2 | not measured | 86.0% |
| aa-lcr | not measured | 83.3% |
| mmmu-pro | not measured | 78.5% |
| ifbench | not measured | 75.4% |
| terminal-bench hard | not measured | 53.0% |
| critpt | not measured | 16.9% |
each column describes the tested configuration named under the model; performance and costs can differ on impossibl. a score one model was not measured on is left blank rather than scored zero. indices are ranked against every model on the gateway with one. last checked 2026-09-10.
estimate your cost
one token workload, priced on every model at the published rates, in usd. change the numbers to match yours.
openai/gpt-5.3-codex
estimated usage cost
$8.75
1,000 requests × (1,000 uncached input × $1.75 + 500 output × $14.00) / 1,000,000 = $8.75
base rates; no context pricing tiers are published.
estimates use published impossibl api usage rates. configured billing adjustments, funding fees, taxes, and custom workspace rates are excluded and may change the final amount.
image and audio usage, cache creation, and additional tool charges are excluded. reasoning tokens count as billable output, even when they are not visible in the response.
summary
Claude Opus 5.5 and GPT-5.3 Codex are available through the Impossibl API. they share the /v1/chat/completions endpoint; the model identifier selects the model for a request.
Claude Opus 5.5 is created by Anthropic. It has a 1,000,000-token context window. Base API pricing (USD): $4.00 per million input tokens; $20.00 per million output tokens.
GPT-5.3 Codex is created by OpenAI. It has a 400,000-token context window. Base API pricing (USD): $1.75 per million input tokens; $14.00 per million output tokens.
Claude Opus 5.5 →GPT-5.3 Codex →
this page compares Claude Opus 5.5 vs GPT-5.3 Codex as listed by the impossibl public api. prices and availability come from that catalog, refreshed here every five minutes. this is an impossibl offering, not a comparison of independent hosting-provider quotes.
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