# Changelog

Max Prilutskiy·Updated3 days ago·5 min read

What's new in Lingo.dev - releases, improvements, and fixes.

## [May 2026#](/content/en/changelog#may-2026/index.html)

- **[API keys](/content/en/docs/platform/api-keys/index.html) · Personal vs Service** - API keys now come in two flavours. Personal keys inherit the creator's RBAC role and per-engine grants — same as before. Service keys are a new Enterprise-only construct decoupled from any one user, with their own role and/or per-engine scope. A service key can be roleless and reach only the engines listed on it, mirroring how a user without an org role still has access via `engine_users` rows. Anti-escalation guards apply on create and edit (role limited to `engine:access`, caller must hold every engine in scope). If the Enterprise plan ends, service keys deactivate with a typed 403 that names the entitlement, instead of a phantom "no engine scope" error.
- **MCP · OAuth login** - The [Lingo.dev MCP server](/content/en/docs/platform/mcp/index.html) now supports browser-redirect OAuth alongside token auth. Claude.ai, Claude Desktop, and other MCP clients can connect without copy/pasting API keys, and engines are configurable from inside the client.
- **Sync API · Usage metrics in response** - The [synchronous localize endpoint](/content/en/docs/api/localize#response/index.html) now returns the LLM model used, LLM cost, and localization token cost per request. Enables per-translation cost attribution down to the individual end user.
- **Async API · Locked keys** - The [async localization API](/content/en/docs/api/localization#create-localization-jobs/index.html) now accepts `lockedKeys`. Locked values are preserved verbatim across target languages and bypass the LLM - for slugs, URL parameters, identifiers, and any key whose value is structural metadata rather than translatable content.
- **Platform UI · Retrieved context in Log tab** - For every localization request, the engine retrieves the context used to produce that specific translation - glossary items, instructions, and brand voice. The Log tab now surfaces all of it per request, making it clear exactly which context shaped each translation.
- **Platform UI · Per-model billing breakdown** - The billing page now splits cost and token usage by model across configured engines, instead of showing totals only. Makes it clear which models are driving spend.

## [April 2026#](/content/en/changelog#april-2026/index.html)

- **Async API · Localization pipeline** - Optional stages that wrap the core translate step in the [async localization API](/content/en/docs/api/localization/index.html), turning a single API call into a full translation workflow. Each stage is independently toggleable per engine and overridable per job. Full reference: [Async Localization Pipeline](/content/en/docs/api/pipeline/index.html).
  - [Pre-localization AI edit](/content/en/docs/api/pipeline#pre-localization-ai-edit/index.html) - an AI agent cleans the source payload (typos, grammar, spelling) before translation, so a single source error doesn't propagate across every target locale.
  - [Post-localization human review](/content/en/docs/api/pipeline#post-localization-human-review/index.html) - the AI translation is sent to a qualified human translator who edits it for clarity, consistency, and accuracy. The job pauses on a webhook until the human output returns, with a configurable timeout (default 48h).
  - [Post-localization AI review](/content/en/docs/api/pipeline#post-localization-ai-review/index.html) - after the human edit, an AI agent reconciles the human output against engine-level rules (glossary, brand voice, instructions). Catches cases where a translator's word choice conflicts with engine config. Requires human review enabled.
  - [Back-translation check](/content/en/docs/api/pipeline#back-translation-check/index.html) - the final translation is translated back into the source locale and compared against the original. An AI agent flags semantic drift by severity (`minor`, `major`, `critical`) and auto-adjusts the forward translation when major or critical drift is detected. Automates a classic human-QA technique.
- **Async API · AI engine provisioning** - New [Async Provisioning API](/content/en/docs/api/provisioning/index.html) that takes a fresh engine plus user-provided context (URLs, raw content) and auto-configures the brand voice, glossary, and instructions. An AI agent crawls the sources, extracts the configuration, and applies it to the engine - turning multi-step manual setup into a single API call.
- **Platform · AI reviewers** - Major expansion of [AI reviewers](/content/en/docs/platform/ai-reviewers/index.html): per-engine configurability plus two built-in reviewers that replace hand-written quality checks for the most common cases.
  - **Per-engine configurability** - reviewers are now applied per engine instead of globally. The same organization-level library of reviewers can be enabled for the engines that need a given check and skipped for the ones that don't, so a strict legal-content reviewer doesn't run on marketing copy and a casual-tone reviewer doesn't run on a regulated engine. Built-in reviews toggle independently per engine on the Reviews tab.
  - **Built-in [Glossary items AI review](/content/en/docs/platform/ai-reviewers#glossary-items-ai-review/index.html)** - automatically checks whether each translation respected the engine's glossary rules: custom translations (e.g., "Deploy" → "Bereitstellen") and non-translatable terms (e.g., "OAuth") alike. Accounts for grammatical variations, so one glossary entry covers every inflected form. Returns a per-item breakdown with pass/fail and reasoning for each glossary entry, making the exact missed rule visible at a glance. Replaces hand-written custom reviewers for every glossary term.
  - **Built-in [Instructions AI review](/content/en/docs/platform/ai-reviewers#instructions-ai-review/index.html)** - evaluates each engine instruction independently against the translation. Three instructions produce three pass/fail verdicts, each with its own reasoning when failed. Supports N/A results when an instruction doesn't apply to the content (e.g., a formality rule on a translation that's just a product name); N/A is excluded from aggregate scores so quality metrics stay accurate. Replaces a custom reviewer per instruction.
- **Platform UI · New quality reports** - Two new entries on the [Reports](/content/en/docs/platform/reports/index.html) page that turn the built-in AI reviews into time-series quality signals.
  - **[Terminology Coverage](/content/en/docs/platform/reports#terminology-coverage/index.html)** - tracks how consistently glossary terms are applied correctly over time. Daily line shows coverage percentage (correctly applied terms ÷ total relevant terms); bars show the absolute number of terms applied. A high terms-applied count combined with a falling coverage rate is an early warning that the glossary or engine config needs attention as volume scales. Filterable by engine and month.
  - **[Instruction Adherence](/content/en/docs/platform/reports#instruction-adherence/index.html)** - tracks how consistently the engine's [instructions](/content/en/docs/platform/instructions/index.html) are followed over time. The percentage is calculated only across reviews where instructions were actually relevant - tooltips show `followed / relevant` so the rate and sample size are both visible. Useful for verifying that newly added instructions actually change behavior, and for catching regressions after a model swap or prompt change.

## [v1.0 - March 2026#](/content/en/changelog#v1.0---march-2026/index.html)

Lingo.dev `v1.0` introduces localization engines - stateful translation APIs that teams configure once and call from backend code, CLI, or CI/CD.

- **[Localization engines](/content/en/docs/platform/engines/index.html)** - configure models, brand voice, instructions, and glossaries per locale
- **[LLM models](/content/en/docs/platform/llm-models/index.html)** - pick from the full OpenRouter catalog, with fallback chains for reliability
- **[Brand voices](/content/en/docs/platform/brand-voices/index.html)** - define linguistic rules and tone per locale
- **[Instructions](/content/en/docs/platform/instructions/index.html)** - set per-locale translation rules for specific patterns
- **[Glossaries](/content/en/docs/platform/glossaries/index.html)** - lock down product terminology across languages and builds
- **[AI Reviewers](/content/en/docs/platform/ai-reviewers/index.html)** - custom cross-model evaluation criteria for translation quality
- **[Playground](/content/en/docs/platform/playground/index.html)** - test engine configurations before they go live
- **[Reports](/content/en/docs/platform/reports/index.html)** - word generations, token consumption, top locales, glossary coverage, change rates