> ## Documentation Index > Fetch the complete documentation index at: https://docs.gostudio.ai/llms.txt > Use this file to discover all available pages before exploring further. # Remove a watermark > Submits an image for watermark removal. This is the endpoint most integrations should use — it validates the request, runs the generation, writes a generation log, and deducts credits in one call. **This call blocks until the image is ready.** Fast models return almost immediately. Slower models are polled server-side on your behalf, so the response still arrives as a completed `200` — but it can take up to four minutes, and the request is cut off at five. Set your client's HTTP timeout accordingly; the default in most HTTP libraries is far too short. You never need to poll this endpoint's result yourself, and there is no fire-and-forget mode — the call always holds the connection until the generation finishes, and the completed `200` body is returned either way. A `webhook_url` gets you a second copy of that same result payload `POST`ed to your server; it does not shorten the request. On the `lite` tier that webhook is delivered once, on success only. On the async tiers (`pro`, `advance`) it can also arrive with `status: "failed"` and an `error` field when the provider reports a failure — alongside the HTTP error response — and a completed job may be delivered more than once. Treat deliveries as idempotent and key them on `job_id`; do not assume `output_urls` are byte-identical across two deliveries of the same job. If an async job (`pro` / `advance`) is accepted by the provider and is later reported failed, the response is `500 internal_error`, not `502`. The generation is still marked failed and the credits reserved for it are refunded. Handle all `5xx` responses uniformly rather than matching on a specific status. Allowed callers: `user`. An internal service token passes the auth gate but carries no user context, so it cannot submit a generation here. ## OpenAPI ````yaml /openapi.yaml post /api/v2/apps/watermark-remover openapi: 3.0.3 info: title: GoStudio Watermark Remover API version: 2.0.0 description: > The Watermark Remover endpoints of the GoStudio v2 REST API. Every response uses a standard envelope: successes return `{ status, data }`; errors return `{ status, error: { type, code, dev, message } }`. Every endpoint here takes a **Supabase user JWT** as a Bearer token. An `internal` service token is accepted by the auth layer but carries no user identity, so it cannot be used to generate or look up a job. The one exception is the provider callback, which is authenticated by signature rather than by a caller token. servers: - url: https://www.gostudio.ai description: Production security: - bearerAuth: [] tags: - name: Watermark Remover description: AI watermark removal — orchestration, model metadata, and job polling. - name: Webhooks description: Endpoints called by external services, not by your application. paths: /api/v2/apps/watermark-remover: post: tags: - Watermark Remover summary: Remove a watermark description: > Submits an image for watermark removal. This is the endpoint most integrations should use — it validates the request, runs the generation, writes a generation log, and deducts credits in one call. **This call blocks until the image is ready.** Fast models return almost immediately. Slower models are polled server-side on your behalf, so the response still arrives as a completed `200` — but it can take up to four minutes, and the request is cut off at five. Set your client's HTTP timeout accordingly; the default in most HTTP libraries is far too short. You never need to poll this endpoint's result yourself, and there is no fire-and-forget mode — the call always holds the connection until the generation finishes, and the completed `200` body is returned either way. A `webhook_url` gets you a second copy of that same result payload `POST`ed to your server; it does not shorten the request. On the `lite` tier that webhook is delivered once, on success only. On the async tiers (`pro`, `advance`) it can also arrive with `status: "failed"` and an `error` field when the provider reports a failure — alongside the HTTP error response — and a completed job may be delivered more than once. Treat deliveries as idempotent and key them on `job_id`; do not assume `output_urls` are byte-identical across two deliveries of the same job. If an async job (`pro` / `advance`) is accepted by the provider and is later reported failed, the response is `500 internal_error`, not `502`. The generation is still marked failed and the credits reserved for it are refunded. Handle all `5xx` responses uniformly rather than matching on a specific status. Allowed callers: `user`. An internal service token passes the auth gate but carries no user context, so it cannot submit a generation here. operationId: removeWatermark requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/WatermarkRequest' examples: lite: summary: Default model value: image_url: https://example.com/watermarked.jpg tier: summary: Named tier with webhook value: image_url: https://example.com/watermarked.jpg model_id: pro webhook_url: https://your-app.com/webhooks/gostudio responses: '200': description: Generation completed synchronously. content: application/json: schema: type: object properties: status: type: integer example: 200 data: $ref: '#/components/schemas/WatermarkSyncResult' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '402': $ref: '#/components/responses/PaymentRequired' '403': $ref: '#/components/responses/Forbidden' '422': $ref: '#/components/responses/UnprocessableContent' '429': $ref: '#/components/responses/RateLimited' '500': $ref: '#/components/responses/ServerError' '502': $ref: '#/components/responses/BadGateway' '503': $ref: '#/components/responses/ServiceUnavailable' '504': $ref: '#/components/responses/GatewayTimeout' components: schemas: WatermarkRequest: type: object required: - image_url properties: image_url: type: string format: uri description: > Publicly accessible `http`/`https` URL of the watermarked image. The API fetches it server-side, so it must not sit behind authentication or a firewall. example: https://example.com/watermarked.jpg model_id: type: string description: > Model to run. Accepts either a full model ID or one of the friendly tier aliases `lite`, `pro`, `advance`. Defaults to `dewatermark/watermark-remover-pro` (the `lite` tier). Cost per run: `lite` 4 credits, `pro` 4 credits, `advance` 10 credits. Call `/info` for the authoritative figures rather than hard-coding these — both the model list and the pricing can change. default: dewatermark/watermark-remover-pro example: pro prompt: type: string description: > Optional guidance. Ignored by models whose `requires_prompt` is `false` in the info response. webhook_url: type: string format: uri description: > HTTPS URL to receive the result when the generation finishes. Must be HTTPS; an `http://` URL is rejected with `400 invalid_webhook_url`. Delivery is best-effort and fire-and-forget: the `POST` is sent once and never retried, the response status is ignored, and there is no signature header. If a delivery is missed, reconcile with `GET /api/v2/apps/watermark-remover/{jobId}`. example: https://your-app.com/webhooks/gostudio WatermarkSyncResult: type: object properties: job_id: type: integer example: 12345 status: type: string enum: - completed model_id: type: string example: dewatermark/watermark-remover-pro output_urls: type: array description: CDN URLs for the cleaned images, usable immediately. items: type: string format: uri credits_deducted: type: number example: 4 credit_balance: type: number description: Remaining balance after this request. example: 38 ErrorResponse: type: object properties: status: type: integer example: 400 error: type: object properties: type: type: string example: validation_error code: type: string example: invalid_input dev: type: integer example: 40001 message: type: string example: Some information is invalid. responses: BadRequest: description: The request was malformed or failed validation. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: status: 400 error: type: validation_error code: invalid_input dev: 40001 message: Some information is invalid. Unauthorized: description: Missing or invalid Authorization Bearer token. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: status: 401 error: type: authentication_error code: unauthorized dev: 40100 message: Missing or invalid Authorization Bearer token. PaymentRequired: description: The account does not have enough credits for this request. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: status: 402 error: type: billing_error code: insufficient_credits dev: 40200 message: You don't have enough credits. Forbidden: description: Caller type not allowed for this endpoint. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: status: 403 error: type: permission_error code: forbidden dev: 40300 message: You don't have permission for this action. UnprocessableContent: description: > The request was well-formed but the content could not be processed — for example the image was rejected by the model or flagged as NSFW. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: status: 422 error: type: provider_error code: content_filtered dev: 42205 message: >- We couldn't generate this image. Please try a different prompt or image. RateLimited: description: Too many requests. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: status: 429 error: type: rate_limit_error code: rate_limited dev: 42900 message: You're doing that too often. Please wait a moment. ServerError: description: Unexpected server error. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: status: 500 error: type: system_error code: internal_error dev: 50000 message: Something went wrong on our end. BadGateway: description: > The upstream model provider rejected the submission, was unreachable, or returned an unusable response while the job was being submitted or checked. The generation is marked failed and the credits reserved for it are refunded. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: status: 502 error: type: provider_error code: provider_bad_gateway dev: 50200 message: Generation is having trouble right now. Please try again. ServiceUnavailable: description: > A dependency is temporarily unavailable. Auth-dependent endpoints return `service_unavailable` (dev 50300) when the auth provider is down; generation endpoints return `model_unavailable` (dev 50301) when the model provider is. Both are safe to retry with backoff. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: status: 503 error: type: system_error code: service_unavailable dev: 50300 message: Auth service is temporarily unavailable. GatewayTimeout: description: > The upstream model provider took too long to respond, or server-side polling gave up after 240 seconds without a result. The generation is marked failed and the credits reserved for it are refunded. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: status: 504 error: type: provider_error code: generation_timeout dev: 50400 message: The request took too long. Please try again. securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT description: > Supabase user JWT (or an internal service token). Send as `Authorization: Bearer `. ````