> ## Documentation Index > Fetch the complete documentation index at: https://api-docs.voicecheap.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # Edit saved subtitles > Update saved SRT and layout using its latest revision. A stale revision is rejected so concurrent edits cannot overwrite one another. Update saved SRT and layout using its latest revision. A stale revision is rejected so concurrent edits cannot overwrite one another. ```http theme={null} POST https://api.voicecheap.ai/v1/actions/subtitles_history_update ``` ## Authentication and permissions Send a VoiceCheap API key in this header. Authorization: Bearer with the same API key is also supported. OAuth access tokens are accepted only by MCP, not by this REST endpoint. Required permissions: `subtitles:write`. An active paid subscription is required. Permissions do not change team roles, resource ownership, media credits, or plan limits. ## Parameters Text value. Minimum length: 1. Maximum length: 160. Pattern: `^[A-Za-z0-9_-]+$`. Text value. Minimum length: 1. Maximum length: 2097152. Integer value. Maximum: 9007199254740991. JSON object. See the complete input schema for its nested fields. JSON object. See the complete input schema for its nested fields. Optional at the transport boundary: the server injects an identifier before validation when omitted. Supply your own stable UUID v4 to recover safely from a lost response. Format: "uuid". Pattern: `^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-4[0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$`. The JSON Schema below preserves the exact field names, nested types, defaults, bounds, and accepted values exposed by discovery. Additional cross-field rules are listed in the operation notes. ```json theme={null} { "type": "object", "properties": { "historyId": { "type": "string", "minLength": 1, "maxLength": 160, "pattern": "^[A-Za-z0-9_-]+$" }, "currentSrtContent": { "type": "string", "minLength": 1, "maxLength": 2097152 }, "expectedRevision": { "type": "integer", "exclusiveMinimum": 0, "maximum": 9007199254740991 }, "layoutOptions": { "type": "object", "properties": { "maxLinesPerCaption": { "anyOf": [ { "type": "number", "const": 1 }, { "type": "number", "const": 2 }, { "type": "number", "const": 3 } ] }, "maxCharactersPerLine": { "type": "integer", "minimum": 24, "maximum": 64 } }, "required": ["maxLinesPerCaption", "maxCharactersPerLine"], "additionalProperties": false }, "styleOptions": { "type": "object", "properties": { "fontFamily": { "type": "string", "enum": ["sans", "serif", "mono"] }, "fontSize": { "type": "string", "enum": ["small", "medium", "large"] }, "textColor": { "type": "string", "enum": ["white", "yellow", "cyan"] }, "backgroundStyle": { "type": "string", "enum": ["outline", "box", "shadow"] }, "position": { "type": "string", "enum": ["bottom", "middle"] } }, "required": ["fontFamily", "fontSize", "textColor", "backgroundStyle", "position"], "additionalProperties": false }, "requestId": { "description": "UUID v4 for this action. Reuse the same ID with identical arguments on retries.", "type": "string", "format": "uuid", "pattern": "^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-4[0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$" } }, "required": ["historyId", "currentSrtContent", "expectedRevision"], "additionalProperties": false } ``` ## Idempotency Use a UUID v4 in requestId or the Idempotency-Key HTTP header for each mutation. Reuse the same identifier and identical arguments after a network failure. If both are supplied, they must match. Replaying a saved request does not repeat the operation or charge another monthly call. Failed or interrupted requests are not restarted automatically. Every mutation can return HTTP 202 when a retry finds the same request still running, even when its first execution is normally synchronous. If execution completed but resultStored is false, a retry returns HTTP 200 with saved request state instead of the original result. Retrieve the output through its domain history, result, or download action. ## Request examples Replace example resource identifiers and media keys with values returned for your account. Keep the request identifier stable when retrying the same mutation. ```bash cURL theme={null} curl --request POST 'https://api.voicecheap.ai/v1/actions/subtitles_history_update' \ --header "x-api-key: $VOICECHEAP_API_KEY" \ --header 'Content-Type: application/json' \ --data '{"historyId":"history_20261016_001","currentSrtContent":"1\n00:00:00,000 --> 00:00:01,500\nHello world.\n","expectedRevision":1,"layoutOptions":{"maxLinesPerCaption":2,"maxCharactersPerLine":42},"styleOptions":{"fontFamily":"sans","fontSize":"medium","textColor":"white","backgroundStyle":"outline","position":"bottom"},"requestId":"13579bdf-2468-4ace-8bdf-0123456789ab"}' ``` ```javascript JavaScript theme={null} const input = { historyId: 'history_20261016_001', currentSrtContent: '1\n00:00:00,000 --> 00:00:01,500\nHello world.\n', expectedRevision: 1, layoutOptions: { maxLinesPerCaption: 2, maxCharactersPerLine: 42, }, styleOptions: { fontFamily: 'sans', fontSize: 'medium', textColor: 'white', backgroundStyle: 'outline', position: 'bottom', }, requestId: '13579bdf-2468-4ace-8bdf-0123456789ab', }; const response = await fetch('https://api.voicecheap.ai/v1/actions/subtitles_history_update', { method: 'POST', headers: { 'x-api-key': process.env.VOICECHEAP_API_KEY, 'Content-Type': 'application/json', }, body: JSON.stringify(input), }); const body = await response.json(); if (!response.ok) throw new Error(body.code + ': ' + body.message); console.log(body); ``` ```python Python theme={null} import os import requests response = requests.post( "https://api.voicecheap.ai/v1/actions/subtitles_history_update", headers={"x-api-key": os.environ["VOICECHEAP_API_KEY"]}, json={"historyId": "history_20261016_001", "currentSrtContent": "1\n00:00:00,000 --> 00:00:01,500\nHello world.\n", "expectedRevision": 1, "layoutOptions": {"maxLinesPerCaption": 2, "maxCharactersPerLine": 42}, "styleOptions": {"fontFamily": "sans", "fontSize": "medium", "textColor": "white", "backgroundStyle": "outline", "position": "bottom"}, "requestId": "13579bdf-2468-4ace-8bdf-0123456789ab"}, timeout=120, ) body = response.json() if not response.ok: raise RuntimeError(f"{body.get('code')}: {body.get('message')}") print(body) ``` ## Response A successful first execution returns HTTP 200 with the operation result under data. A replay may return saved request state instead. The example shows one supported response, not every optional field. The same editable subtitle history ID with its incremented revision, update timestamp and normalized current SRT. ```json HTTP 200 theme={null} { "data": { "historyId": "history_20261016_001", "revision": 2, "updatedAt": 1792152010000, "currentSrtContent": "1\n00:00:00,000 --> 00:00:01,500\nHello world.\n" }, "requestId": "13579bdf-2468-4ace-8bdf-0123456789ab" } ``` ```json HTTP 202 replay_running theme={null} { "data": { "requestId": "13579bdf-2468-4ace-8bdf-0123456789ab", "operation": "subtitles_history_update", "createdAt": 1792144800000, "updatedAt": 1792144820000, "status": "running", "pollAfterSeconds": 5 }, "requestId": "13579bdf-2468-4ace-8bdf-0123456789ab" } ``` ```json HTTP 200 replay_completed_without_result theme={null} { "data": { "requestId": "13579bdf-2468-4ace-8bdf-0123456789ab", "operation": "subtitles_history_update", "createdAt": 1792144800000, "updatedAt": 1792144820000, "status": "completed", "resultStored": false, "message": "The action completed. Retrieve its output from the corresponding history or resource action." }, "requestId": "13579bdf-2468-4ace-8bdf-0123456789ab" } ``` ## Result fields | Field | Description | | - | - | | `data.historyId` | Existing saved subtitle item. | | `data.revision` | Previous revision plus one. | | `data.updatedAt` | Unix update timestamp in milliseconds. | | `data.currentSrtContent` | Validated, sorted and normalized saved SRT text. | ## Recover and poll this request Use the same identifier even after a lost connection. If resultStored is false, retrieve the output through the corresponding history, result, or download action. Never start a second generation merely to check progress. ```bash theme={null} curl --request POST 'https://api.voicecheap.ai/v1/actions/action_request_get' \ --header "x-api-key: $VOICECHEAP_API_KEY" \ --header 'Content-Type: application/json' \ --data '{"requestId":"13579bdf-2468-4ace-8bdf-0123456789ab","operation":"subtitles_history_update"}' ``` ```json HTTP 200 theme={null} { "data": { "requestId": "13579bdf-2468-4ace-8bdf-0123456789ab", "operation": "subtitles_history_update", "status": "completed", "createdAt": 1792144800000, "updatedAt": 1792144820000, "resultStored": true, "result": { "historyId": "history_20261016_001", "revision": 2, "updatedAt": 1792152010000, "currentSrtContent": "1\n00:00:00,000 --> 00:00:01,500\nHello world.\n" } } } ``` ## Operation notes * Requires a paid subscription and the action permission. The actor's personal tool plan is rechecked at execution; saved tools and upload references belong to that actor, including when the credential is associated with a team. * A successful action uses one shared monthly API/MCP call. Beginner allows 500, Starter 5,000 and Creator 25,000 calls/month; Pro, Scale and Enterprise have no monthly ceiling. Per-minute limits still apply: 30, 60, 120, 180, 300 and 600 respectively. Tool generation allowances are separate. * Use a UUID v4 requestId, or an identical Idempotency-Key header, and retain the same action, ID and arguments on retries. A cached replay does not use another monthly call. * Read subtitles\_history\_get first, then pass its revision as expectedRevision. A stale revision returns VIDEO\_TO\_SRT\_HISTORY\_CONFLICT and cannot overwrite another edit. * SRT cues are parsed, sorted and normalized; they must not overlap or exceed the source media duration plus 0.5 seconds. Input is bounded to 2 MiB of UTF-8 SRT. * Omitted layoutOptions and styleOptions are normalized to the standard defaults (2 lines, 42 characters, sans/medium/white/outline/bottom), rather than implicitly preserving prior custom values. Include both when retaining customized formatting. * This edits text and formatting in saved SRT history. It does not render a new video, transcribe again, consume a media upload or use another daily generation allowance. ## Usage Each successful invocation consumes one monthly API/MCP call. Media credits and the operation's own generation allowances also apply. ## Errors | HTTP status | Code | Meaning or recovery | | - | - | - | | 400 | `CREDENTIAL_IN_QUERY` | Credentials were supplied in an access\_token or api\_key query parameter. Send credentials in headers. | | 400 | `IDEMPOTENCY_CONFLICT` | The header and body request IDs differ. | | 400 | `INVALID_REQUEST_ID` | requestId or Idempotency-Key is not a UUID v4. | | 400 | `VALIDATION_ERROR` | Arguments do not satisfy the action schema, or an unknown argument was supplied. | | 400 | `VIDEO_TO_SRT_HISTORY_INVALID_SRT` | SRT cue text or timestamp structure is invalid. | | 400 | `VIDEO_TO_SRT_HISTORY_OUTSIDE_MEDIA` | A cue ends beyond the recorded source duration plus its 0.5-second tolerance. | | 400 | `VIDEO_TO_SRT_HISTORY_OVERLAP` | At least two subtitle cues overlap. | | 400 | `VIDEO_TO_SRT_HISTORY_SRT_TOO_LARGE` | Edited SRT exceeds the 2 MiB UTF-8 limit. | | 401 | `API_KEY_EXPIRED` | The API key has expired. | | 401 | `INVALID_API_KEY` | Provide a valid, unexpired API key. | | 401 | `INVALID_CREDENTIAL` | The Authorization header is malformed or conflicts with x-api-key. | | 401 | `MISSING_CREDENTIAL` | No usable header credential was supplied, or it exceeded 4096 characters. | | 401 | `USER_NOT_FOUND` | The credential's account no longer exists. | | 403 | `ACCOUNT_UNAVAILABLE` | The acting or billing account is unavailable or being deleted. | | 403 | `AMBIGUOUS_TEAM_API_KEY` | The credential's user belongs to more than one team, so the billing context is ambiguous. | | 403 | `INSUFFICIENT_SCOPE` | The API key or MCP connection lacks the required action permission. | | 403 | `INTEGRATION_PLAN_UNSUPPORTED` | The account's integration limits could not be verified. | | 403 | `PAID_SUBSCRIPTION_REQUIRED` | The authenticated actor no longer has a paid subscription when this tool action executes. | | 403 | `SUBSCRIPTION_REQUIRED` | Use an active paid subscription. | | 403 | `TEAM_OWNER_NOT_FOUND` | The effective team owner account could not be found. | | 404 | `VIDEO_TO_SRT_HISTORY_NOT_FOUND` | The actor-owned editable subtitle history item does not exist. | | 409 | `CONCURRENT_ACTION_LIMIT_REACHED` | This account already has 10 integration actions running. Poll an existing request before starting another. | | 409 | `IDEMPOTENCY_CONFLICT` | Reuse an identifier only with the same operation and arguments. | | 409 | `VIDEO_TO_SRT_HISTORY_CONFLICT` | expectedRevision is stale. Read subtitles\_history\_get again and use the current revision before retrying the edit. | | 429 | `INTEGRATION_MONTHLY_LIMIT_REACHED` | Used and pending calls have reached the shared monthly API/MCP allowance. | | 429 | `INTEGRATION_RATE_LIMIT_REACHED` | The account has reached its per-minute integration limit; inspect retryAfterSeconds. | | 500 | `INTERNAL_ERROR` | Check saved request state and resource history before deciding to retry a mutation. | | 503 | `ACTION_RESULT_UNAVAILABLE` | The action ran but request-result persistence could not be confirmed. Poll the same action and requestId and inspect resource history before starting another write. | | 503 | `SERVER_RESTARTING` | The server is restarting. Retry shortly and keep the same request identifier for a mutation. | ```json theme={null} { "code": "INSUFFICIENT_SCOPE", "message": "This credential does not permit the requested action.", "status": 403, "details": { "requiredScopes": ["subtitles:write"] } } ``` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.