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API Reference
Custom Tags

Custom Tags

Manually tag individual entities with your own tags, sectors, types, and notes. Tags are merged into /follows/enriched and /classify responses. All tag operations are free.

Limit: 10,000 tagged entities per account (100,000 on Enterprise). A 429 is returned at the cap.


Add/Update Tags

POST /v1/tagsFree

Upserts by entity — posting again for the same entity updates the existing tag record.

curl -X POST https://frontrun.vc/v1/tags \
  -H "X-API-Key: your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "username": "stealth_ai_co",
    "tags": ["portfolio", "series-a"],
    "custom_sector": "AI Infrastructure",
    "notes": "Series A target Q2."
  }'

Parameters

ParameterTypeDefaultDescription
twitter_user_idstring (body)--Entity's X user ID. Required unless username is set.
usernamestring (body)--Entity's X username. Required unless twitter_user_id is set. Must already exist in Frontrun's classification cache — a 404 is returned otherwise.
tagsstring[] (body)--Custom tags
custom_sectorstring (body)--Sector override
custom_entity_typestring (body)--Entity type override
notesstring (body)--Free-text notes

Response

Returns 201 with the tag record:

{
  "id": "c2d8e1f0-7b6a-4c5d-8e9f-1a2b3c4d5e6f",
  "twitter_user_id": "1234567890",
  "username": "stealth_ai_co",
  "tags": ["portfolio", "series-a"],
  "custom_sector": "AI Infrastructure",
  "custom_entity_type": null,
  "notes": "Series A target Q2.",
  "updated_at": "2026-07-08T14:00:00.000Z"
}

List Tags

GET /v1/tagsFree

# All tagged entities
curl "https://frontrun.vc/v1/tags" \
  -H "X-API-Key: your_api_key"
 
# Filter by tag
curl "https://frontrun.vc/v1/tags?tag=portfolio" \
  -H "X-API-Key: your_api_key"
 
# Filter by custom sector
curl "https://frontrun.vc/v1/tags?sector=DeFi" \
  -H "X-API-Key: your_api_key"

Parameters

ParameterTypeDefaultDescription
tagstring (query)--Only entities carrying this exact tag.
sectorstring (query)--Only entities whose custom_sector matches. Case-insensitive partial match.

Response

{
  "count": 1,
  "tags": [
    {
      "id": "c2d8e1f0-7b6a-4c5d-8e9f-1a2b3c4d5e6f",
      "twitter_user_id": "1234567890",
      "username": "stealth_ai_co",
      "tags": ["portfolio", "series-a"],
      "custom_sector": "AI Infrastructure",
      "custom_entity_type": null,
      "notes": "Series A target Q2.",
      "updated_at": "2026-07-08T14:00:00.000Z"
    }
  ]
}

Sorted by most recently updated.


Remove Tags

DELETE /v1/tags/:twitter_user_idFree

Removes all custom tags, overrides, and notes for the entity.

curl -X DELETE https://frontrun.vc/v1/tags/1234567890 \
  -H "X-API-Key: your_api_key"
{
  "deleted": true,
  "twitter_user_id": "1234567890"
}

Returns 404 if the entity has no tags.