Configuration

The relay reads its settings from a .env file and from the process environment. The process environment wins, so an orchestrator can override one value without editing the file. Every problem is reported at startup in one list, and the relay refuses to start until they are fixed.

The annotated template is deploy/.env.example. Sizes take a plain byte count or a unit: 500MB, 5GiB, 1.5GiB.

Required

Variable	Description
`TPP_PUBLIC_BASE_URL`	The address devices use, scheme included and no trailing path: `https://tpp.example.com`. Creation links and their QR codes are built from it, and an `https://` value marks the admin cookie `Secure`.
`ADMIN_PASSWORD`	The admin page password. (`ADMIN_PASSWORD_HASH` is reserved for later; setting it stops the relay from starting.)

Server

Variable	Default	Description
`TPP_HTTP_ADDR`	`:8080`	Listen address. Plain HTTP.
`TPP_HOST_PORT`	`8080`	Compose only: the host port the container is published on.
`TPP_HOST_BIND_ADDR`	`127.0.0.1`	Compose only: the host address the port is published on. Change it only when the proxy is on another machine, and name one private interface — never `0.0.0.0`.
`TPP_LOG_LEVEL`	`info`	`debug`, `info`, `warn` or `error`. Even `debug` never logs clipboard content.
`TPP_ADMIN_SESSION_TTL`	`12h`	How long an admin sign-in lasts.
`TPP_SOURCE_URL`	`https://github.com/Mark7888/two-place-paste`	Where the Source code link on the admin and pairing pages points. If you run a modified relay for other people, set it to your version’s source — see License.

Redis

Variable	Default	Description
`TPP_REDIS_ADDR`	`127.0.0.1:6379`	Redis address. In the compose file: `redis:6379`.
`TPP_REDIS_PASSWORD`	(empty)	Redis password, if any.
`TPP_REDIS_DB`	`0`	Redis database number.

Blob storage

Variable	Default	Description
`TPP_BLOB_BACKEND`	`disk`	`disk` or `s3`. See Blob storage.
`TPP_BLOB_ROOT`	`/var/lib/tpp/blobs`	Where the disk backend writes.
`TPP_BLOB_SWEEP_INTERVAL`	`10m`	How often expired blobs are removed, after the pass at startup.

S3 (with `TPP_BLOB_BACKEND=s3`)

Variable	Default	Description
`TPP_S3_ENDPOINT`	(empty = AWS)	`host[:port]`, optionally with `http://` or `https://`.
`TPP_S3_USE_SSL`	`true`	`false` for an `http://` endpoint.
`TPP_S3_REGION`	`us-east-1`	Region.
`TPP_S3_BUCKET`	—	Required.
`TPP_S3_PREFIX`	(empty)	Key prefix, so a bucket can be shared.
`TPP_S3_ACCESS_KEY_ID`, `TPP_S3_SECRET_ACCESS_KEY`	(empty)	Static credentials. Both empty uses the AWS credential chain. Each has a `_FILE` variant that reads it from a file (Docker secrets).
`TPP_S3_PATH_STYLE`	`auto`	`auto`, `path` or `virtual`. Auto is path-style for a custom endpoint, virtual-host for AWS.
`TPP_S3_CREATE_BUCKET`	`false`	Create the bucket at startup if it is missing.

Storage limits

Variable	Default	Description
`TPP_BLOB_MAX_TOTAL_BYTES`	`0` (unlimited)	All blob storage. Set it a little under the volume’s size.
`TPP_BLOB_MAX_GROUP_BYTES`	`1GiB`	Per group, so one busy group cannot push out everyone else’s entries. At least `TPP_ENTRY_MAX_BYTES`.
`TPP_BLOB_MIN_FREE_BYTES`	`0` (off)	Disk backend: refuse new blobs while the volume has less than this free.

When a new entry would not fit, the oldest entries are removed to make room — see Storage limits and eviction.

Entry limits

These are sizes of ciphertext; the relay never knows the plaintext size.

Variable	Default	Description
`TPP_ENTRY_INLINE_MAX_BYTES`	`256KiB`	Entries up to this size are kept in Redis; larger ones go to the blob store.
`TPP_ENTRY_MAX_BYTES`	`50MiB`	Hard cap per entry.
`TPP_ENTRY_CHUNK_BYTES`	`8MiB`	Chunk size for entries over 10 MiB. At most 10 MiB; with S3 at least 5 MiB.
`TPP_UPLOAD_SESSION_TTL`	`10m`	How long an unfinished chunked upload may sit idle (1m–1h).

Store limits

The store keeps items a group saves on purpose, beside its 24-hour history. It is off for every group until you turn it on from the group’s page in the admin. Its limits are separate from the blob limits above, and the store never evicts: a save that does not fit is refused, and the app says how much room is left. Sizes count each item’s ciphertext plus about 2 KiB of fixed record.

Variable	Default	Description
`TPP_STORE_MAX_TOTAL_BYTES`	`0` (unlimited)	Every group’s store together.
`TPP_STORE_MAX_GROUP_BYTES`	`100MiB`	One group’s store, unless its tag or the group itself overrides it. `0` is unlimited.
`TPP_STORE_MAX_ITEM_BYTES`	`TPP_ENTRY_MAX_BYTES`	The largest item, so anything that fits in history can be saved.
`TPP_STORE_MAX_GROUP_ITEMS`	`1000`	Items per group. Each one is a record of about 2 KiB in Redis.