# Retrieve a marketing template version `GET /api/v1/marketing-templates/{templateId}/versions/{versionId}` One immutable snapshot, byte for byte as it was published. THIS IS THE ROUTE THAT ANSWERS "WHAT DID THAT CAMPAIGN ACTUALLY SEND": a campaign records the version id it rendered, and this resolves it however many times the merchant has rewritten the template since. Nothing can change this row. The version table is append-only, there is no write that touches it, and the database role serving this API holds no UPDATE or DELETE grant on it. THE VERSION IS ADDRESSED UNDER ITS PARENT and the parent is part of the lookup, not decoration: a version id belonging to a different template of the same store is a 404 here rather than a body from the wrong message. ## Path parameters - `templateId` (string, required) - `versionId` (string, required) ## Responses - `200` — Success - `400` — The request was refused before any state changed. `code` is one of: `invalid_body`, a write body this route will not take. `reason` partitions it and `field` names the key when one key is at fault. `invalid_query`, a query parameter, including limit and after. `invalid_text`, a NUL byte or bytes that are not valid UTF-8 anywhere in the path, the query or the body. Strip control characters before sending. `idempotency_key_required`, a write sent without the Idempotency-Key header. `invalid_request`, an Idempotency-Key longer than 255 bytes. Routes add their own codes for rules only they know. Switch with a default arm. - `401` — No credential, or one this API does not accept. `code` is always `unauthorized`. THE BODY IS DELIBERATELY UNINFORMATIVE. An expired key, a revoked key, a publishable key, a key belonging to another merchant and a key that never existed are all refused with the same bytes, so this response cannot be used to probe which keys exist. Check the key's state in the dashboard rather than inferring it here. Send the key as `Authorization: Bearer ` or as `X-API-Key: `. It is never accepted in a query string. - `403` — The key lacks the read_marketing_campaigns scope. `code` is `insufficient_scope` and the message names the scope to ask the merchant for. - `404` — The resource this url addresses does not exist, or never did on this store. `resource` names the kind of thing that was missing and is the half to branch on: the code is `not_found` on newer routes and a per-entity spelling on routes that shipped before that rule, and the two mean the same thing. A 404 is ALWAYS about the url. An id inside the request body that resolves to nothing is 422 `unprocessable_reference` instead, so the two cases stay distinguishable. An id that belongs to a different merchant reads exactly like one that never existed. - `429` — Too many requests. `code` is `rate_limited`. Two limits apply independently: one on the credential and the route family, one on the client address. The headers describe whichever has less left, so honouring Retry-After always clears the window that bound. - `default` — Any status this operation does not list, in the same envelope. A 5xx means the request may or may not have applied. Retry it with the SAME Idempotency-Key: that is the only way to find out without risking a duplicate, and it is what the key is for. A few 4xx conditions arrive here rather than as a listed status because they depend on the merchant's plan or on a module being wired: 402 when a quota or a plan limit is reached, and 503 when a capability the route needs is not configured on this deployment. Both carry a `code` naming which. ## Example ```bash curl --request GET \ --url 'https://api.mercemur.com/api/v1/marketing-templates/{templateId}/versions/{versionId}' \ --header 'Authorization: Bearer ' ```