# Claude Haiku 5.5

> Claude Haiku 5.5 is Anthropic's newest Haiku, released on October 7, 2026 as the successor to Claude Haiku 4.5. Anthropic builds it for high-volume, latency-sensitive work such as classification, routing, extraction and sub-agent tasks, and lists it as the fastest model in its current lineup. It carries a 1M-token context window and up to 128K output tokens, takes image input, and runs adaptive thinking by default at a default effort of "medium."

Canonical: https://routemux.com/anthropic/claude-haiku-5-5
Provider: Anthropic

## Key facts

| Field | Value |
| --- | --- |
| Model ID | anthropic/claude-haiku-5-5 |
| Official model ID | claude-haiku-5-5 |
| Context window | 1M |
| Max output | 128K |
| Input modalities | text, image |
| Output modalities | text |
| Capabilities | Vision, Reasoning, Tool Calling, Coding, Cache, Paid Cache Write |
| Upstream release | 2026-10-07 |
| Availability | available |

## Pricing

- RouteMux input: $0.03 per 1M tokens
- RouteMux output: $0.15 per 1M tokens
- Official input: $0.1 per 1M tokens
- Official output: $0.5 per 1M tokens
- Cache read: $0.003 per 1M tokens
- Cache write: $0.0375 per 1M tokens
- Saving vs official: 70%
- Official price source: anthropic_x0.30, verified 2026-10-10

Billing is prepaid wallet, charged per successful request only.

## API access

Base URL: https://api.routemux.com

Supported protocols:

- anthropic_messages

## What is Claude Haiku 5.5

Claude Haiku 5.5 is Anthropic's newest Haiku, released on October 7, 2026 as the successor to Claude Haiku 4.5. Anthropic builds it for high-volume, latency-sensitive work such as classification, routing, extraction and sub-agent tasks, and lists it as the fastest model in its current lineup. It carries a 1M-token context window and up to 128K output tokens, takes image input, and runs adaptive thinking by default at a default effort of "medium."

Anthropic prices Haiku 5.5 by prompt length, and RouteMux follows the same two tiers. For prompts up to 100K tokens it costs $0.03 per 1M input tokens against Anthropic's $0.10, and $0.15 per 1M output against $0.50. When a prompt goes over 100K tokens, the whole request moves to the higher tier: $0.15 input and $0.75 output per 1M, against Anthropic's $0.50 and $2.50. Prompt caching follows the same split; up to 100K, cache reads are $0.003 per 1M tokens and writes are $0.0375 (5-minute) or $0.06 (1-hour). Failed and timed-out requests are not billed.

Moving over from Haiku 4.5 is more than a model-name change: Anthropic lists several request shapes that Haiku 4.5 accepted and Haiku 5.5 rejects. They are covered in the FAQ below.

## Key capabilities

- **Fastest in Anthropic's lineup** — Anthropic rates Haiku 5.5 the fastest current Claude model and positions it for classification, routing, extraction and sub-agent work.
- **Two price tiers by prompt length** — $0.03 / 1M input and $0.15 / 1M output up to 100K prompt tokens; $0.15 and $0.75 above that.
- **1M-token context, 128K output** — Up from Haiku 4.5's 200K context — though prompts past 100K tokens are billed at the higher tier.
- **Adaptive thinking, steered by effort** — Thinking is on by default at medium effort. Anthropic suggests low for chat and simple high-volume requests, and high for knowledge work and strict instruction following.

## Other variants in this family

- Claude Haiku 4.5 (`anthropic/claude-haiku-4.5`)

## Sources

- [Anthropic — Claude Haiku 5.5](https://platform.claude.com/docs/en/models/haiku-5-5/overview)
- [Anthropic — Claude Haiku 5.5 migration guide](https://platform.claude.com/docs/en/models/haiku-5-5/migration-guide)
- [Anthropic — Pricing](https://platform.claude.com/docs/en/about-claude/pricing)

_Content reviewed by Jerry Fan on 2026-10-10._