Anthropic API / Anthropic API

Portkey Gateway rewrites service_tier to deprecated Anthropic 'speed' field causing 400 errors

Fix Anthropic API 400 error when using service_tier through Portkey gateway Includes evidence for Anthropic API troubleshooting demand.

Source-backed Last updated May 12, 2026 1 source Needs local verification

Category: Anthropic API
Error signature: Claude API 400 Bad Request — service_tier rewritten to deprecated 'speed' field
Quick fix: Compare the failing environment with a known working setup, then change one configuration value at a time.
Updated: May 12, 2026
Verification status: Source-backed
Evidence: 1 public source URL

Before you change production

This page includes public source URLs in the imported troubleshooting record. Compare those references with your version and environment before applying changes.

Reproduce the smallest failing action and save non-secret logs before changing configuration.
Check versions for Anthropic API, related SDKs, package managers, CI runners, and hosting providers.
Change one setting or dependency at a time, then rerun the same failing command or request.
Avoid destructive commands, credential rotation, billing changes, or security relaxations without a rollback plan.

What this error means

Claude API 400 Bad Request — service_tier rewritten to deprecated 'speed' field is a Anthropic API failure pattern reported for developers trying to fix anthropic api 400 error when using service_tier through portkey gateway. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Official Portkey-AI/gateway GitHub issue. Portkey gateway translates OpenAI-style service_tier to Anthropic's deprecated 'speed' field per docs-core #869, but Anthropic's Messages API no longer accepts 'speed' — it uses service_tier natively. Result: any request with service_tier set returns HTTP 400. Priority Tier unreachable through gateway.

Common causes

Developers using Portkey as an LLM gateway to route requests to the Anthropic API receive HTTP 400 errors because Portkey incorrectly translates OpenAI-style service_tier to Anthropic's deprecated 'speed' field. This makes Priority Tier (fast mode) completely unreachable through the gateway, blocking production workloads that depend on reduced latency.
Official Portkey-AI/gateway GitHub issue. Portkey gateway translates OpenAI-style service_tier to Anthropic's deprecated 'speed' field per docs-core #869, but Anthropic's Messages API no longer accepts 'speed' — it uses service_tier natively. Result: any request with service_tier set returns HTTP 400. Priority Tier unreachable through gateway.

Quick fixes

Confirm the exact error signature matches Claude API 400 Bad Request — service_tier rewritten to deprecated 'speed' field.
Check the Anthropic API account, local tool state, and provider configuration involved in the failing workflow.
Compare the failing environment with a known working setup, then change one configuration value at a time.

Platform/tool-specific checks

Verify the command, editor, extension, or API client that produced the error.
Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

Capture the exact error message and the command, editor action, or request that triggered it.
Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
Review the source evidence below and compare it with your environment.
Apply one change at a time and rerun the smallest failing action.
Keep the working fix documented for the team or deployment environment.

How to prevent it

Keep provider/tool configuration documented.
Record non-secret diagnostics such as tool version, provider name, model name, and command path.
Add a lightweight check before CI or production workflows depend on the tool.

Diagnostic flow for this page

Match Claude API 400 Bad Request — service_tier rewritten to deprecated 'speed' field exactly before applying the quick fix.
Compare the failing environment with Anthropic API versions, account scope, provider settings, and deployment context.
Check the listed common causes in order, starting with the cause that best matches your logs.
Use the evidence status below to decide whether to confirm against public sources or official documentation.
Apply one reversible change, rerun the smallest failing action, and keep rollback notes.

FAQ

What does Claude API 400 Bad Request — service_tier rewritten to deprecated 'speed' field mean in Anthropic API?

Claude API 400 Bad Request — service_tier rewritten to deprecated 'speed' field indicates the workflow described by "Portkey Gateway rewrites service_tier to deprecated Anthropic 'speed' field causing 400 errors" failed in a Anthropic API context. Start by confirming the exact signature and the component that emitted it.

What should I check first for Claude API 400 Bad Request — service_tier rewritten to deprecated 'speed' field?

Check whether this cause matches your environment: Developers using Portkey as an LLM gateway to route requests to the Anthropic API receive HTTP 400 errors because Portkey incorrectly translates OpenAI-style service_tier to Anthropic's deprecated 'speed' field. This makes Priority Tier (fast mode) completely unreachable through the gateway, blocking production workloads that depend on reduced latency.

Is the Claude API 400 Bad Request — service_tier rewritten to deprecated 'speed' field guidance source-backed?

The "Portkey Gateway rewrites service_tier to deprecated Anthropic 'speed' field causing 400 errors" page is labeled source-backed. It has 1 public source URL from github.com, so use that evidence status when deciding how much additional verification you need.

When should I avoid the quick fix for Claude API 400 Bad Request — service_tier rewritten to deprecated 'speed' field?

For "Portkey Gateway rewrites service_tier to deprecated Anthropic 'speed' field causing 400 errors", avoid applying "Compare the failing environment with a known working setup, then change one configuration value at a time." when the error text differs, the affected version or provider is different, or the change would touch credentials, billing, DNS, production deploy settings, or irreversible data.

What should I collect before debugging Claude API 400 Bad Request — service_tier rewritten to deprecated 'speed' field?

For "Portkey Gateway rewrites service_tier to deprecated Anthropic 'speed' field causing 400 errors", collect the failing Anthropic API command or request, non-secret configuration, versions, timestamps, request IDs when available, and the smallest reproduction that still triggers the signature.