Pinecone 404: index not found usually means wrong project, not a typo

TL;DR: A 404 on an index that should exist is most often the API key of a different project, or a name with a case or dash error. Verify project, then name, then existence. Index names are lowercase alphanumeric plus dashes, no dots. Run pc.list_indexes() with the same client and key.

The error

404 Not Found: The requested resource does not exist.

The fix

1. Wrong project. The API key belongs to project A; the index lives in project B. Keys are per-project. This is the most common cause and the one agents check last.
2. Name mismatch. Index names are lowercase alphanumeric plus dashes, no dots. My-Index, my.index, and my-index are three different strings and only the last can exist.
3. Actually deleted. Someone deleted it, or deletion protection blocked a recreate you expected to succeed. pc.list_indexes() shows what is really there.
4. Wrong control plane region for pods. Pod environments are region-specific strings; a pod index created in one environment is not visible from another.
5. Run pc.list_indexes() with the same client and key. If the index is absent, the key or project is wrong, not the code.
6. Compare the name character by character against the console. Copy it; do not retype it.
7. If it was deleted, recreate it (with the spec) and re-ingest. There is no undelete.

When to use this

• You are seeing this exact error message; match the block above, not just part of it.
• The failing call matches the scenario in the title: Pinecone 404.
• You want the fastest verified fix before digging through logs.

When not to use this

• Your error text differs from the block above; close cousins often have different causes.
• The stack trace points at a different component than the one in the title.
• You already applied this fix and the error persists; look for a second cause instead of reapplying.

Compatibility

• Not pinned to a specific version; follows current Pinecone behavior.

Pinecone's error-handling guide defines 404 as the requested resource not existing and advises verifying the name and deletion state. The manage-api-keys guide documents per-project keys. Verified against live docs 2026-09-26.