Changelog

October 2026

Usage API — costs in US$, prompt-cache totals

• cost_usd on /v1/usage/summary, /v1/usage/logs and /v1/usage/logs.csv (and the get_usage_summary / list_usage_logs MCP tools) is now the US$ you were billed at the published rate (1 credit = ₹1, US$1 = ₹96). It was previously reported in internal billing units (0.01 per credit), about 4% below the US$ amount; credits = US$ × 96. Past rows are converted the same way, so a window spanning the change stays consistent.
• /v1/usage/summary reports prompt-cache usage: totals.total_cache_read_tokens, totals.total_cache_creation_tokens, and cache_read_tokens / cache_creation_tokens per service. input_tokens keeps its meaning (the uncached part of the prompt).

Per-model parameters follow each model's documentation

• Output limits — GET /api/v1/models now lists max_output_tokens where a model documents one, and max_tokens above it returns 400 max_tokens_too_large on /v1/chat/completions, /v1/responses and /v1/messages. The gemini-* models now allow up to 65,536 output tokens (previously capped at 8,192), and an omitted max_tokens leaves the model's own default.
• reasoning_effort — xhigh and max now reach every model instead of being cut to high first; each model maps them to its own top level. DeepSeek-V4-Pro/-Flash and glm-5.2 now honour their levels, nemotron-3-super switches to its low-effort mode for low/none, sarvam-105b switches thinking fully off for none, and gpt-5-mini uses minimal. See API speed.
• Sarvam — when you omit max_tokens, we send 4,096 (16,384 for glm-5.3) so thinking no longer cuts answers short at 2,048. A glm-5.3 or gemma-4-31b request over 10 MB returns 413.
• Models — gpt-4.1 serves a 300,000-token context window. The realtime gpt-realtime-2* models take 32,000 input and 4,096 output tokens. nova-sonic was retired upstream on 2026-09-14 and returns 503; use nova-sonic-2.
• Images and speech — image sizes outside a model's range, and negative_prompt on lucid-origin, return 400. gpt-4o-mini-tts has 13 voices and rejects an unknown voice with 400. gpt-4o-transcribe-diarize returns speaker segments with response_format verbose_json or diarized_json; it is no longer accepted as a voice-session stt_model (422), because live transcription cannot label speakers. grok-4.3 reasoning tokens now count as output tokens, and its images must have at least 512 pixels.

Email domains — neutral 502 reason

• The 502 returned by the email domain routes when provisioning or verification is temporarily unavailable now carries reason: "provider_unavailable". Deployments still being upgraded may return the older acs_unavailable for the same condition; status, body shape and retry advice are identical, so match both strings. See Email limits.

Voice session webhooks

• voice_session.ended and voice_session.failed now fire exactly once per session, on every way a session can end (the agent hanging up, DELETE, the session timing out), and only after the end has been saved. If two end signals arrive together, the first one decides end_reason and duration_seconds.
• A session that ends because the agent hit an error (end_reason: "agent_error") now has status failed and fires voice_session.failed on every path; it previously fired voice_session.ended for some sessions. See Webhooks.

Speech-to-text error codes

• /v1/audio/transcriptions and /v1/audio/translations now return 400 invalid_request for a problem with the request (unsupported audio, a streaming-only or unknown model), 429 rate_limit_exceeded when rate limited, and 502 service_unavailable when transcription is temporarily unavailable, the same code /v1/audio/speech uses. See Speech-to-Text.

Batch API, zero data retention, per-end-user budgets and prompt caching

• Batch API — OpenAI-compatible POST /v1/files and POST /v1/batches: upload a JSONL file of requests, run it asynchronously, and download the results. Gated by the key's llm permission. See Batch API.
• Zero data retention — send "provider": {"zdr": true} to route a request only to models that keep no data, or enforce it for a whole key or account. See Gateway controls.
• Per-end-user budgets — monthly credit caps per end user of your app, managed under /api/v1/gateway/end-user-budgets (scopes end_user_budgets:read / end_user_budgets:write). See Gateway controls.
• Prompt caching — prompt_cache_key on /v1/chat/completions and /v1/responses passes through as a cache-routing hint to the models that support it (and is dropped elsewhere); cache_control blocks on /v1/messages are accepted so Anthropic SDK code runs unchanged, but explicit breakpoints are not applied yet — caching works from the prompt prefix. usage.prompt_tokens_details.cached_tokens is now always present, and the Usage API reports cache reads and writes.

Payments, evals, contacts and telephony

• Customer payment links — agents can send payment links on calls and WhatsApp that are paid into your own connected Razorpay account. Track them under /api/v1/payment-requests and subscribe to the payment_request.* webhook events.
• Evals — an llm_judge assertion, a pass-rate gate for CI, and creating an eval case from a real call. See Voice evals.
• WhatsApp identities on contacts — contacts carry whatsapp_bsuid, whatsapp_parent_bsuid and whatsapp_username, for WhatsApp users who hide their phone number. A BSUID is unique per account like a phone number or email. See Contacts.
• TRAI readiness for outbound campaigns — a readiness check for AI outbound calling under the TCCCPR amendment. See Voice campaigns.

Newly documented

• Contacts (/api/v1/contacts, plus each contact's memory), the handoff queue (/api/v1/handoffs), integrations and sheet automations (/api/v1/integrations, /api/v1/sheet-automations), payment requests, and POST /api/v1/crm/csv/inspect were already callable with an API key and now have reference pages.
• Webhooks — the delivery body, the X-CallMissed-Event / X-CallMissed-Delivery headers, the retry schedule, and the call.amd_detected event.
• Idempotency and Errors — rewritten to match exactly what the API does.

September 2026

Account MCP server — run your account from an AI assistant

• Account MCP server — connect Claude, ChatGPT or any MCP client to https://api.callmissed.com/api/v1/mcp, sign in with your CallMissed account or an API key, and act on your account through 331 tools: voice agents, calls and campaigns, the inbox, CRM, support desk, WhatsApp, email and more. Every tool is gated by the key's scopes, spending tools are marked, and destructive ones ask first. See Account MCP.
• Multilingual voice agents — voice tiers and custom agents accept an auto-detect language, so one agent can answer in the caller's language. See Voice tiers.

New model — GPT-6.1 Sol

• gpt-6.1-sol — OpenAI's GPT-6.1 Sol: near-Astra performance for complex coding, computer use and professional work at a lower cost. 1.05M context, 128K output, text + image input, reasoning and tool calling. $2.083 in / $10.42 out per 1M tokens ($0.1042 cached input).
• Long prompts — requests with more than 272K input tokens are billed at 2× input and cached-input rates and 1.5× output for the whole request ($4.167 in / $0.2083 cached / $15.63 out per 1M).
• reasoning_effort — accepts low, medium (default), high and xhigh. The model always reasons, so none and minimal are sent as low, and max is sent as xhigh. Only the default temperature is supported, and max_tokens must be at least 3. See API speed.
• Paid plans only. See Models.

New models — GPT-6 Sol and GPT-6 Luna

• gpt-6-sol — OpenAI's GPT-6 frontier reasoning model for enterprise agents, coding and complex knowledge work; succeeds gpt-5.6-sol. 1.05M context, 128K output, text + image input, reasoning and tool calling. $2.083 in / $10.42 out per 1M tokens ($0.2083 cached input).
• gpt-6-luna — the efficient GPT-6 model for high-volume, cost-sensitive workloads; succeeds gpt-5.6-luna. Same 1.05M context, vision, reasoning and tools. $0.1042 in / $0.5208 out per 1M tokens ($0.01042 cached input).
• Long prompts — requests with more than 272K input tokens are billed at 2× input and cached-input rates and 1.5× output for the whole request.
• reasoning_effort — both accept none, low, medium, high and xhigh (minimal is sent as low). When a request includes tools, reasoning is set to none automatically. max_tokens must be at least 3. See API speed.
• Paid plans only. See Models.

August 2026

Managed Voice Agent — speech-to-speech over one WebSocket

• Managed Voice Agent — a full speech-to-speech pipeline behind a single WebSocket. Stream microphone audio in, get synthesized speech and conversation events back; speech recognition, the language model, text-to-speech, turn-taking and interruption handling are all run and tuned for you. No WebRTC and no client SDK. Two protocols on the same host and the same engine: wss://api.callmissed.com/v2/voice/agent (CallMissed-native) and wss://api.callmissed.com/v1/agent/converse (Deepgram Voice Agent compatible — an existing Deepgram integration can repoint its URL and work unchanged). Supports in-call tool calling, live model/prompt/voice updates, and sessions up to 2 hours. See Managed Voice Agent.
• Voice model catalogue — GET /api/v1/voice/models lists every selectable speech-to-text, language and text-to-speech model with a measured latency verdict (eligible, too_slow, unsupported, unmeasured) plus its p50, sample count and budget. Any eligible combination is valid. Models too slow to hold a conversation are not offered — they are listed with the reason, rather than silently disappearing or being offered with a caveat. Verdicts come from real production traffic, not vendor claims, and a model with too few samples reads unmeasured rather than being assumed fast.

Embeddings, usage API, CRM, support desk and voice-agent operations

• Embeddings — POST /v1/embeddings, OpenAI-compatible. text-embedding-3-small (1536 dims, $0.02083 / 1M input tokens) and text-embedding-3-large (3072 dims, $0.1354 / 1M). Batches of up to 128 inputs, optional dimensions shortening and base64 output. Both are free-plan callable, taking the free tier to 27 models across five categories. Gated by the key's llm permission. See Embeddings.
• Usage API — GET /v1/usage/summary, /logs and /logs.csv return your own metering rows for the last 90 days, filterable by service, model, key, session_id and trace_id. Scope usage:read. See Usage API.
• Gateway tooling — server-side prompt management with versions, labels, presets and free rendering; response cache stats and purge; and bring your own provider key with liveness verification and a write-only secret.
• CRM — companies, notes and tasks, deals and pipelines, custom fields and saved views, search, bulk and CSV, and lead scoring with a unified timeline.
• Support desk — tickets with server-managed lifecycle stamps, SLA policies with business hours and live breach reporting, macros, tags and routing rules with a dry-run evaluator, and CSAT/NPS surveys and a hosted page where customers answer.
• Voice-agent operations — eval suites (up to 50 cases per run, credit-charged), A/B experiments with deterministic assignment, and agent squads with handoff simulation and credit-charged agent drafting.
• WhatsApp — Flows (create, publish, read submissions) and catalog orders.

New models — Cartesia Ink STT

• ink-whisper — Cartesia's fastest and most affordable STT at $0.1875 / hour, across 100 languages including Hindi, Urdu and Tamil. Better accuracy than baseline Whisper, and dynamic chunking that cuts hallucination during pauses and silence. Works for both file transcription and voice sessions. See Speech to Text.
• ink-2 — Cartesia's top-ranked STT for voice agents at $0.5625 / hour: 8% WER on AppTek's 14-accent call-centre benchmark, against 10% for Deepgram Flux and 12% for ElevenLabs. Self-detects turns, so no separate turn detector is needed. Two limits: it is English only, and it is voice-session only — the file transcription endpoint returns 400 and points you to ink-whisper. See Speech to Text.

New models — conversational Indic LLM, Saaras V4 STT, Flux TTS

• sarvam-105b-conversations — 105B MoE tuned for conversation and voice. 128K context, tool calling, streaming, hybrid thinking. Free-tier, same $0.3646 in / $0.3646 out per 1M as sarvam-105b. See Indic Models.
• saaras:v4 — Sarvam STT with five output modes (transcribe, translate, verbatim, transliterate, code-mix) across 24 languages. Free-tier at $0.3125 / hour. See Speech to Text.
• Deepgram Flux TTS — streaming-first TTS built for voice agents: turn-based synthesis with prosody carried across turns. 36 English voices including priya (Indian-accented English, the default). English only, no expressive controls. Available only through the managed Voice Agent (tts_engine: "flux"), billed inside the per-minute voice rate. See Voices.
• Free tier — now 27 models (11 LLM, 4 STT, 4 TTS, 6 image, 2 embedding).

Model catalog update — retired models

• Retired LLM IDs — the following model IDs are no longer served: openai/gpt-5.4-pro, openai/gpt-5.4, openai/gpt-5.4-mini, openai/gpt-5.4-nano, anthropic/claude-opus-4.6, anthropic/claude-sonnet-4.6, anthropic/claude-haiku-4.5, x-ai/grok-4.20, qwen/qwen3.5-plus, qwen/qwen3.5-flash, mistralai/mistral-small-2603, and the auto auto-router.
• Migration — use the first-party flagships (gpt-5.6-sol, gpt-5.6-terra, gpt-5.6-luna, gpt-5.5, grok-4.3) or the direct-routed free tier (kimi-k2.6, kimi-k2.7-code, glm-5.2, gpt-oss-120b, mistral-small-3.1). See Models.
• Free tier — now 24 models (11 LLM). The auto free auto-router is retired; pick a free model explicitly.
• Endpoints unchanged — POST /v1/chat/completions and the Anthropic-compatible POST /v1/messages both continue to work and accept every current catalog ID.

June 2026

v1.6.0 — WebRTC Voice, Image Generation & Web Search

• WebRTC voice sessions — POST /v1/voice/sessions returns a connection token + URL; CallMissed handles the STT→LLM→TTS pipeline. List, fetch, fetch transcript (json | txt | srt), and end sessions under /v1/voice/sessions. The legacy /ws/voice-agent WebSocket still works for backward compatibility. See Voice Session API.
• Image Generation API — POST /v1/images/generations (OpenAI-compatible). Free models include flux-2-klein-9b, flux-2-dev, lucid-origin, phoenix-1.0, sdxl-lightning, dreamshaper-8-lcm; paid models include flux-2-pro, flux-1.1-pro, nano-banana-2, and nano-banana-pro. See Image Generation.
• Web Search API — POST /v1/search defaults to Serper web search (Exa, Firecrawl also available); flat 1 credit per query. See Web Search.
• Knowledge RAG — vector knowledge sources at /api/v1/knowledge/sources (ingest text, URL, or PDF; chunked + embedded) with semantic search at POST /api/v1/knowledge/search.

May 2026

v1.5.0 — First-Party Models, Account Security & WhatsApp Platform

• First-party models — deployments callable by bare ID: gpt-4o, gpt-4.1, gpt-5-mini, grok-4.3, DeepSeek-V4-Pro, DeepSeek-V4-Flash, plus first-party STT (whisper, gpt-4o-transcribe, gpt-4o-mini-transcribe, gpt-4o-transcribe-diarize) and TTS (gpt-4o-mini-tts).
• More STT/TTS — whisper-large-v3-turbo (99 langs), nova-3 (diarization), aura-2-en / aura-2-es, and melotts — all free-tier.
• Kimi K2.6 — kimi-k2.6 added to the direct-routed free tier alongside kimi-k2.5.
• TOTP 2FA & passkeys — two-factor auth (authenticator apps + backup codes) and passkeys for dashboard sign-in. Active sessions can be reviewed and revoked from the dashboard.
• WhatsApp platform — Embedded Signup onboarding, message templates, broadcast campaigns, and delivery analytics under /api/v1/whatsapp/*. See WhatsApp API.
• Billing surfaces — coupon redemption, downloadable PDF invoices, and a credit ledger broken down by transaction type, all in the dashboard.
• Audit log — a sensitive-action audit feed in the dashboard.

April 2026

v1.4.0 — Anthropic API Compatibility & Audio Translation

• Anthropic Messages API — New POST /v1/messages endpoint. Use the Anthropic SDK with CallMissed by changing only the base_url. Full streaming support with Anthropic SSE lifecycle (message_start, content_block_delta, message_stop).
• Dual auth headers — Anthropic endpoint accepts both x-api-key and Authorization: Bearer headers
• Model aliasing — A bare model name on the Anthropic endpoint resolves against the CallMissed catalog
• Audio Translation — New POST /v1/audio/translations endpoint. Translate audio in 24 languages to English text. OpenAI SDK compatible (client.audio.translations.create())
• Token counting — POST /v1/messages/count_tokens for input token estimation
• Anthropic rate limit headers — anthropic-ratelimit-requests-limit, anthropic-ratelimit-requests-remaining, etc.

v1.3.0 — Voice Agent & Ultra-Low-Latency Pipeline

• Voice Agent WebSocket — Real-time STT→LLM→TTS pipeline over /ws/voice-agent. PCM audio in, streaming MP3 out. LLM and TTS run concurrently for minimum latency.
• PCM AudioWorklet capture — Raw PCM s16le at 16kHz, no container overhead
• Streaming MP3 playback — MediaSource API appends and plays chunks as they arrive
• Profile management — Save and update user profile from the dashboard

v1.2.0 — Security, Google OAuth & Plan Enforcement

• Sign in with Google — Google sign-in for the dashboard. Auto-creates the organisation and user, and links to an existing account by email.
• OTP Authentication — Email-based OTP for passwordless login and password reset
• Plan limit enforcement — Server-side usage caps per plan tier (free/starter/pro/enterprise). API returns 429 quota_exceeded when limits reached. Usage headers (X-RateLimit-*, X-Usage-Warning) on every response.
• Per-API-key rate limiting — a requests-per-minute limit on every key (today set by plan; see Rate limits)
• Model catalog update — OpenAI gpt-5.4 family, Anthropic Claude 4.6, Google Gemini 3.1, xAI Grok 4.20, Qwen 3.5, Mistral Small
• Knowledge Base file upload — Upload PDF, DOCX, TXT files (max 20 MB) with auto text extraction
• Bot deployment verification — Verify WhatsApp/Twilio channel connectivity from the dashboard
• Settings verification — Verify WhatsApp, Twilio, and Indic LLM API connectivity

v1.1.0 — Platform Playground

• Playground rebuild — LLM (streaming + non-streaming), STT (file upload + mic), TTS (37 voices across 11 Indian languages), Voice Agent demo

v1.0.0 — Initial Release

• Chat Completion API — OpenAI-compatible endpoint with streaming, tool calls, and function calling
• Speech to Text — saaras:v3 with 22 Indic language support
• Text to Speech — bulbul:v3 (37 voices across 11 Indian languages)
• WhatsApp Bot — Full WhatsApp Business API integration
• Voice Calling — Twilio-based inbound voice with WebSocket streaming
• Multi-tenant — Complete tenant isolation with role-based access
• API Keys — Scoped API keys with usage tracking
• Webhook Delivery — Outbound webhooks with retry and HMAC signing
• Analytics Dashboard — Real-time conversation and usage analytics
• Model catalog — LLM, STT, TTS and image models from one OpenAI-compatible endpoint