xAI API key: format and detection

What it is

The key authenticates calls to the xAI API. Maskflare's Credentials pack includes a dedicated detector, masked by default.

In Maskflare this is the detector xai_api_key, labelled "xAI API key", category password or access key, in the Credentials pack.

Format

• The literal prefix xai-.
• 80 letters and digits, either case.

How Maskflare recognises it

Prefix, exact length of 80 and the entropy floor of 3.0. A comma, quote, backtick, whitespace, semicolon, escaped newline or the end of the text may follow.

Why this page shows no sample key

A realistic sample key would look like a live credential to secret scanners and to anyone skimming the page, and an obviously fake one would not pass this detector's length and entropy rules. The format above is enough to recognise the key: the prefix, the length and the character set.

Regex and validation caveats

• The prefix xai- is short and could appear in ordinary text, but the 80-character body is what makes a match.
• A key split over lines is not matched.

How to detect it in LLM traffic

Keys appear in configuration for tools that call several providers, so one pasted file often holds this key beside an OpenAI or Anthropic one; each has its own detector and is masked independently.

Maskflare reads the whole request body, including the system prompt, earlier messages and tool arguments, and replaces each match with a token such as mf_mask_d7e0 before the request goes out. Coding agents are covered through hooks that mask tool inputs and results, so a key printed by a shell command does not travel onward in the next prompt. On ChatGPT, browser protection blocks prompts that contain API keys, tokens or private keys outright.

If you build the detection yourself

1. Scan the raw text rather than parsed fields: keys sit in code, JSON strings, headers, shell output and pasted logs, often with no label at all.
2. Match the prefix and the exact length for the xAI API key. Where the key has no fixed prefix, require the provider's name and an assignment next to the value instead of matching any long string.
3. Compute the Shannon entropy of the candidate and reject low values, and keep an allow list of placeholders (${KEY}, repeated characters, the alphabet run), because documentation and templates are full of them.
4. Mask the value before the text is sent anywhere. If the key was already sent, treat it as exposed and rotate it; masking later does not recall it.

How Maskflare handles it

• Protect now, Finance - Protect now, Healthcare, Developer and Monitor first: mask (a reversible token).

The available actions are mask (reversible token), redact, partial, hash, format-preserving encryption, generalize, alert and block. Masked values are kept encrypted for 30 days so that answers can be restored, then they expire; prompts and responses are not logged. The full list of detectors is in the detector reference.

Compliance profiles that include it

All 6 compliance profiles include the Credentials pack, and applying them turns this detector on: HIPAA Safe Harbor, GDPR - EU/EEA, UK GDPR, PCI DSS, US personal data and Switzerland - nDSG health data. A profile is a floor: it never turns anything off or weakens a rule that is already stricter.