Chat completions - MESHROUTER

POST /v1/chat/completions

curl https://api.meshrouter.app/v1/chat/completions \
  -H "Authorization: Bearer $MESH_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"auto","messages":[{"role":"user","content":"Hello"}],"stream":true}'

MESH extensions

Field	Description
`models`	Ordered fallback model list
`route`	`auto` or `fallback`
`privacy`	Privacy-class envelope (see below and MESH privacy)
`response_format`	`text`, `json_object`, or `json_schema`
`tools`	OpenAI-compatible function definitions
`tool_choice`	`auto`, `none`, or a named function

Text, image, and tool messages use the OpenAI-compatible messages shape.

Privacy envelope

{
  "privacy": {
    "class": "protected_provider_route",
    "bestAvailable": false,
    "allowFallbackToLowerClass": false
  }
}

Field	Type	Description
`class`	string	One of `standard_route`, `protected_provider_route`, `private_gateway_route`, `confidential_runtime_route`. Optional.
`bestAvailable`	boolean	Ask MESH to pick the strongest class the selected model supports. Mutually preferred over an explicit `class`.
`allowFallbackToLowerClass`	boolean	If `class` is set and the model can’t earn it, accept the strongest class it CAN earn instead of returning HTTP 422.
`mode` (legacy)	string	`"standard"` → `standard_route`. `"mesh"` → `private_gateway_route`. Continues to work; new code should prefer `class`.
`encryptedPrompt` (legacy)	string	Sealed-prompt envelope for legacy private callers. New code uses `class` instead.

Response privacy block

Every billable chat completion response includes a privacy block:

{
  "model": "mesh/claude-sonnet-4.6",
  "privacy": {
    "class": "protected_provider_route",
    "label": "Protected",
    "mesh_stores_prompts": false,
    "mesh_logs_prompts": false,
    "training_on_prompts": false,
    "upstream_disclosed": false,
    "guarantee": "Uses stricter upstream data-protection requirements. MESH does not store prompts by default and training on prompts is not allowed."
  },
  "usage": { "...": "..." }
}

upstream_disclosed is always false — MESH never tells API consumers which upstream provider served the call. The class is the durable guarantee.

Response headers

Header	Description
`x-mesh-upstream-cost-usd`	Model cost for this call
`x-mesh-margin-usd`	MESH margin
`x-mesh-total-usd`	Total USD drawn from your balance
`x-mesh-receipt-id`	Receipt ID for `/v1/receipts/{id}`

Errors

Status	Code	Meaning
422	`privacy_class_unavailable_for_model`	Requested class is not earnable by the selected model. Set `allowFallbackToLowerClass: true` or pick another model.
503	`privacy_class_runtime_unavailable`	Requested class is in-policy for the model but the runtime (Nitro / attestation) is not currently wired.
503	`margin_floor_violated`	Selected route is below the configured margin floor for the served class.