--- layout: api page_title: KV Store - HTTP API description: |- The /kv endpoints access Consul's simple key/value store, useful for storing service configuration or other metadata. --- # KV Store Endpoints The `/kv` endpoints access Consul's simple key/value store, useful for storing service configuration or other metadata. It is important to note that each datacenter has its own KV store, and there is no built-in replication between datacenters. If you are interested in replication between datacenters, please view the [Consul Replicate](https://github.com/hashicorp/consul-replicate) project. ~> Values in the KV store cannot be larger than 512kb. For multi-key updates, please consider using [transaction](/api/txn). ## Read Key This endpoint returns the specified key. If no key exists at the given path, a 404 is returned instead of a 200 response. For multi-key reads, please consider using [transaction](/api/txn). | Method | Path | Produces | | ------ | ---------- | ------------------ | | `GET` | `/kv/:key` | `application/json` | The table below shows this endpoint's support for [blocking queries](/api/features/blocking), [consistency modes](/api/features/consistency), [agent caching](/api/features/caching), and [required ACLs](/api#authentication). | Blocking Queries | Consistency Modes | Agent Caching | ACL Required | | ---------------- | ----------------- | ------------- | ------------ | | `YES` | `all` | `none` | `key:read` | ### Parameters - `key` `(string: "")` - Specifies the path of the key to read. - `dc` `(string: "")` - Specifies the datacenter to query. This will default to the datacenter of the agent being queried. This is specified as part of the URL as a query parameter. - `recurse` `(bool: false)` - Specifies if the lookup should be recursive and `key` treated as a prefix instead of a literal match. This is specified as part of the URL as a query parameter. - `raw` `(bool: false)` - Specifies the response is just the raw value of the key, without any encoding or metadata. This is specified as part of the URL as a query parameter. - `keys` `(bool: false)` - Specifies to return only keys (no values or metadata). Specifying this implies `recurse`. This is specified as part of the URL as a query parameter. - `separator` `(string: "")` - Specifies the string to use as a separator for recursive key lookups. This option is only used when paired with the `keys` parameter to limit the prefix of keys returned, only up to the given separator. This is specified as part of the URL as a query parameter. - `ns` `(string: "")` - Specifies the namespace to query. If not provided, the namespace will be inferred from the request's ACL token, or will default to the `default` namespace. This is specified as part of the URL as a query parameter. For recursive lookups, the namespace may be specified as '\*' and then results will be returned for all namespaces. Added in Consul 1.7.0. ### Sample Request ```shell-session $ curl \ http://127.0.0.1:8500/v1/kv/my-key ``` ### Sample Response #### Metadata Response ```json [ { "CreateIndex": 100, "ModifyIndex": 200, "LockIndex": 200, "Key": "zip", "Flags": 0, "Value": "dGVzdA==", "Session": "adf4238a-882b-9ddc-4a9d-5b6758e4159e" } ] ``` - `CreateIndex` is the internal index value that represents when the entry was created. - `ModifyIndex` is the last index that modified this key. This index corresponds to the `X-Consul-Index` header value that is returned in responses, and it can be used to establish blocking queries by setting the `?index` query parameter. You can even perform blocking queries against entire subtrees of the KV store: if `?recurse` is provided, the returned `X-Consul-Index` corresponds to the latest `ModifyIndex` within the prefix, and a blocking query using that `?index` will wait until any key within that prefix is updated. - `LockIndex` is the number of times this key has successfully been acquired in a lock. If the lock is held, the `Session` key provides the session that owns the lock. - `Key` is simply the full path of the entry. - `Flags` is an opaque unsigned integer that can be attached to each entry. Clients can choose to use this however makes sense for their application. - `Value` is a base64-encoded blob of data. #### Keys Response When using the `?keys` query parameter, the response structure changes to an array of strings instead of an array of JSON objects. Listing `/web/` with a `/` separator may return: ```json ["/web/bar", "/web/foo", "/web/subdir/"] ``` Using the key listing method may be suitable when you do not need the values or flags or want to implement a key-space explorer. #### Raw Response When using the `?raw` endpoint, the response is not `application/json`, but is instead `text/plain`. ``` )k������z^�-�ɑj�q����#u�-R�r��T�D��٬�Y��l,�ιK��Fm��}�#e�� ``` (Yes, that is intentionally a bunch of gibberish characters to showcase the response) !> **Warning:** Consul versions before 1.9.5, 1.8.10 and 1.7.14 detected the content-type of the raw KV data which could be used for cross-site scripting (XSS) attacks. This is identified publicly as CVE-2020-25864. ## Create/Update Key This endpoint updates the value of the specified key. If no key exists at the given path, the key will be created. | Method | Path | Produces | | ------ | ---------- | ------------------ | | `PUT` | `/kv/:key` | `application/json` | Even though the return type is `application/json`, the value is either `true` or `false`, indicating whether the create/update succeeded. The table below shows this endpoint's support for [blocking queries](/api/features/blocking), [consistency modes](/api/features/consistency), [agent caching](/api/features/caching), and [required ACLs](/api#authentication). | Blocking Queries | Consistency Modes | Agent Caching | ACL Required | | ---------------- | ----------------- | ------------- | ------------ | | `NO` | `none` | `none` | `key:write` | ### Parameters - `key` `(string: "")` - Specifies the path of the key. - `dc` `(string: "")` - Specifies the datacenter to query. This will default to the datacenter of the agent being queried. This is specified as part of the URL as a query parameter. - `flags` `(int: 0)` - Specifies an unsigned value between `0` and `(2^64)-1`. Clients can choose to use this however makes sense for their application. This is specified as part of the URL as a query parameter. - `cas` `(int: 0)` - Specifies to use a Check-And-Set operation. This is very useful as a building block for more complex synchronization primitives. If the index is 0, Consul will only put the key if it does not already exist. If the index is non-zero, the key is only set if the index matches the `ModifyIndex` of that key. - `acquire` `(string: "")` - Supply a session ID to use in a lock acquisition operation. This is useful as it allows leader election to be built on top of Consul. If the lock is not held and the session is valid, this increments the `LockIndex` and sets the `Session` value of the key in addition to updating the key contents. A key does not need to exist to be acquired. If the lock is already held by the given session, then the `LockIndex` is not incremented but the key contents are updated. This lets the current lock holder update the key contents without having to give up the lock and reacquire it. **Note that an update that does not include the acquire parameter will proceed normally even if another session has locked the key.** For an example of how to use the lock feature, check the [Leader Election tutorial](https://learn.hashicorp.com/tutorials/consul/application-leader-elections). - `release` `(string: "")` - Supply a session ID to use in a release operation. This is useful when paired with `?acquire=` as it allows clients to yield a lock. This will leave the `LockIndex` unmodified but will clear the associated `Session` of the key. The key must be held by this session to be unlocked. - `ns` `(string: "")` - Specifies the namespace to query. If not provided, the namespace will be inferred from the request's ACL token, or will default to the `default` namespace. This is specified as part of the URL as a query parameter. Added in Consul 1.7.0. ### Sample Payload The payload is arbitrary, and is loaded directly into Consul as supplied. ### Sample Requests ```shell-session $ curl \ --request PUT \ --data @contents \ http://127.0.0.1:8500/v1/kv/my-key # or $ curl \ --request PUT \ --data-binary @contents \ http://127.0.0.1:8500/v1/kv/my-key ``` ### Sample Response ```json true ``` ## Delete Key This endpoint deletes a single key or all keys sharing a prefix. | Method | Path | Produces | | -------- | ---------- | ------------------ | | `DELETE` | `/kv/:key` | `application/json` | The table below shows this endpoint's support for [blocking queries](/api/features/blocking), [consistency modes](/api/features/consistency), [agent caching](/api/features/caching), and [required ACLs](/api#authentication). | Blocking Queries | Consistency Modes | Agent Caching | ACL Required | | ---------------- | ----------------- | ------------- | ------------ | | `NO` | `none` | `none` | `key:write` | ### Parameters - `dc` `(string: "")` - Specifies the datacenter to query. This will default to the datacenter of the agent being queried. This is specified as part of the URL as a query parameter, and gives "No path to datacenter" error when dc is invalid. - `recurse` `(bool: false)` - Specifies to delete all keys which have the specified prefix. Without this, only a key with an exact match will be deleted. - `cas` `(int: 0)` - Specifies to use a Check-And-Set operation. This is very useful as a building block for more complex synchronization primitives. Unlike `PUT`, the index must be greater than 0 for Consul to take any action: a 0 index will not delete the key. If the index is non-zero, the key is only deleted if the index matches the `ModifyIndex` of that key. - `ns` `(string: "")` - Specifies the namespace to query. If not provided, the namespace will be inferred from the request's ACL token, or will default to the `default` namespace. This is specified as part of the URL as a query parameter. Added in Consul 1.7.0. ### Sample Request ```shell-session $ curl \ --request DELETE \ http://127.0.0.1:8500/v1/kv/my-key ``` ### Sample Response ```json true ```