mcp server

Sats4AI - Bitcoin-Powered AI Tools

40+ Lightning-paid AI tools for agents: calls, SMS, fax, voice, translation. No signup, no keys.

Description as published by the maintainer. Source

• version 1.5.5
• active
• voice
• translation

active — Most recent push to the repository was 2026-08-06. Dashed tags are derived by ZBS Index from the published description, not stated by the maintainer.

What this server can do

53 functions, named and described by the server itself. Parameter names are shown because they say more about what a function does than its name usually does.

ai_call(task, language, paymentId, phoneNumber, beginMessage, durationMinutes)

When your task hits a wall that requires a human — booking, negotiating, navigating IVR menus, getting information from a business — send an AI voice agent to handle the call. The agent follows your instructions, has a real two-way conversation, auto-retries on voicemail (up to 3 attempts), and returns a full transcript with structured analysis. May return state='pending_confirm' with clarification questions if critical info is missing — call confirm_ai_call to proceed. Async — poll with check_job_status(jobType='ai-call'). ~150-250 sats for a 3-min US call. Languages: en-US, en-GB, es-ES, fr-FR, de-DE, ja-JP, zh-CN, multi. Pay with Bitcoin Lightning — no telecom account, no API key, no subscription. When NOT to use: not when you want to drive the conversation with your own LLM (use open_voice_bridge — you keep the brain, we provide PSTN/STT/TTS primitives). Not for one-shot TTS broadcasts or IVR delivery (use place_call). Not for SMS (use send_sms). Requires create_payment with toolName='ai_call', phoneNumber, and durationMinutes. Required: paymentId, phoneNumber, task.

analyze_image(prompt, modelId, paymentId, imageBase64)

Analyze and describe image content, answer visual questions, extract information from screenshots or photos. Uses Qwen VL — multimodal vision-language model with strong OCR, chart reading, and spatial reasoning. 21 sats per image. Pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='analyze_image'. Required: paymentId, prompt, imageBase64.

animate_image(prompt, modelId, duration, paymentId, imageBase64)

Animate a still image into cinematic video with ByteDance Seedance 2.0 — provide a first frame (optionally a last frame) and a prompt to direct the motion. Native audio. Async — returns requestId, poll with check_job_status. 480p/720p/1080p, duration 4-15 seconds, priced per second by resolution. Pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='animate_image'. Required: paymentId, prompt, imageBase64, duration.

await_result(jobType, requestId)

Wait for an async job to finish and return its result in ONE call — no manual polling loop. Pass the requestId + jobType from an async tool (generate_video, animate_image, generate_3d_model, transcribe_audio, epub_to_audiobook, ai_call). If your MCP client opened the request with 'Accept: text/event-stream', this streams live progress (notifications/progress) while it waits, then returns the final result; otherwise it does a single status check and returns immediately (call again until status='COMPLETED'). For long jobs it waits up to ~4 minutes per call, then returns status='IN_PROGRESS' with timed_out=true — call again with the same requestId to keep waiting. Equivalent to check_job_status + get_job_result combined. Free; no payment. Required: requestId, jobType.

boardingpass_wallet(documents, paymentId, documentBase64)

Turn airline boarding passes (PDF or screenshot) into Google Wallet passes with the fields a plain scan drops — boarding zone, gate, boarding time — for a whole family in one go. Returns one save link per passenger plus a single 'add all' link. The original barcode is preserved byte-for-byte so it scans at the gate. Priced 100 sats PER PASS: create_payment with toolName='boardingpass_wallet' and quantity=<number of passes> (if you under-count, the call returns the exact price to re-pay). Image/screenshot files that turn out to carry no extra fields are refunded. Privacy: files are processed in memory and never stored; the save link expires in 30 minutes, so nothing is retained. Pay with Bitcoin Lightning — no account, no card. Required: paymentId.

check_job_status(jobType, requestId)

Poll the status of an async job. Use this after calling any async tool (generate_video, animate_image, generate_3d_model, transcribe_audio, epub_to_audiobook, ai_call) that returns a requestId. Returns JSON: { status: 'queued' | 'processing' | 'completed' | 'failed', requestId, jobType }. For epub-audiobook, also includes progress (0-100) and chapterProgress array. Poll every 5-10 seconds. When status is 'completed', call get_job_result to retrieve the output. When status is 'failed', the response includes an error message — do not retry automatically. This tool is free and does not require payment. Do NOT use for synchronous tools (generate_image, generate_text, etc.) — those return results immediately. Required: requestId, jobType.

check_payment_status(paymentId)

Check whether a Lightning invoice has been paid. Returns JSON: { paid, serviceUsed, refundAllowed, readyToUse, next } — readyToUse=true means paid, not yet consumed, and no refund queued; next says what to do. Call after create_payment to verify the user has paid before calling the target tool. Invoices expire after 10 minutes — if expired, create a new payment. Most MCP clients with a connected wallet pay instantly, so a single check is usually sufficient. This tool is free and does not require payment. Required: paymentId.

clone_voice(model, accuracy, paymentId, voiceFileUrl)

Clone any voice from a single audio sample. Returns a reusable voice_id for text_to_speech — speak in the cloned voice indefinitely. High-fidelity reproduction capturing tone, cadence, and accent. Turbo (faster) or HD (higher quality) modes. 7,500 sats per clone. Pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='clone_voice'. Required: paymentId, voiceFileUrl.

colorize_image(paymentId, model_size, imageBase64)

Colorize black-and-white or grayscale photos. DDColor (dual-decoder, ICCV 2023) — vivid, natural colorization. Impossible for text/vision LLMs. 5 sats per image, pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='colorize_image'. Required: paymentId, imageBase64.

confirm_ai_call(answers, sessionId)

Confirm an AI call after reviewing push-back questions, optionally providing answers to missing info. Required when ai_call returns state='pending_confirm'. Uses the original payment — no new payment needed. Returns call_id for polling with check_job_status(jobType='ai-call'). Required: sessionId.

convert_file(fileUrl, paymentId, fileBase64, extensionTo, extensionFrom)

Convert files between 200+ formats: documents (PDF, DOCX, XLSX), images (PNG, JPG, WEBP, SVG), audio (MP3, WAV, FLAC), video (MP4, AVI, MOV). Industrial-grade conversion engine — preserves formatting and quality. Returns download URL. 100 sats. Pay per request with Bitcoin Lightning — no API key, no account, no subscription needed. Requires create_payment with toolName='convert_file'. Required: paymentId, extensionFrom, extensionTo.

convert_html_to_pdf(html, format, paymentId)

Convert HTML or Markdown to a pixel-perfect PDF. Returns JSON: { url } — a temporary download URL (valid ~1 hour). Great for generating invoices, reports, receipts, or formatted documents programmatically. Supports full HTML/CSS including tables, images (base64 or URL), and inline styles. For Markdown input, set format='markdown'. 50 sats per conversion. Use convert_file instead for converting existing files between formats (e.g., DOCX→PDF). Pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='convert_html_to_pdf'. Required: paymentId, html.

create_payment(ocr, mode, text, prompt, message, modelId, duration, quantity, toolName, resolution, fileContext, phoneNumber, systemPrompt, characterCount, generate_audio, durationMinutes)

Create a Lightning invoice to pay for one AI service call. Returns JSON: { paymentId, invoice (BOLT11), amount (sats), expiresAt }. Each payment covers exactly one tool call — call this once per operation. Typical flow: list_models → create_payment → check_payment_status → call tool. The invoice expires in 10 minutes. Call list_models first to discover modelId values. modelId is optional — omit it to use the default (best) model. Some tools require extra params at payment time because pricing depends on them: generate_text requires prompt (price = f(char count)); text_to_speech requires text (price = f(char count) by tier); transcribe_audio / transcribe_translate take durationMinutes (10 sats/min — declare your audio length, default 1); send_sms, place_call, ai_call require phoneNumber; generate_video requires duration, mode, generate_audio; animate_image requires duration (100 sats/sec); edit_image requires resolution (1K=200, 2K=300, 4K=450 sats); epub_to_audiobook requires characterCount (total text characters in the book — price is per-character by voice tier, minimum 500 sats). If required params are missing, the response includes an error with the missing field names. Required: toolName.

deblur_image(paymentId, task_type, imageBase64)

Recover detail from camera-shake and accidental motion blur. NAFNet (ECCV 2022, SOTA on GoPro/SIDD benchmarks). Best for: handheld shake, bumped camera, whole-frame uniform blur. NOT effective for: intentional panning blur, bokeh/depth-of-field, or artistic motion effects. Also supports denoising (grainy/noisy photos). 110 sats per image (~2 min processing), pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='deblur_image'. Required: paymentId, imageBase64.

detect_nsfw(paymentId, imageBase64)

Classify image safety (normal / suggestive / explicit). Falcons.ai NSFW detection — 100x cheaper and faster than asking an LLM. Returns classification label and boolean is_nsfw flag. Essential for content moderation pipelines. 2 sats per image, pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='detect_nsfw'. Required: paymentId, imageBase64.

detect_objects(query, paymentId, imageBase64, box_threshold, text_threshold)

Detect and locate objects in an image by name. Grounding DINO (open-set detector, ECCV 2024) — describe what to find in natural language, get bounding box coordinates and confidence scores. Structured pixel data agents can't get from vision LLMs. 5 sats per image, pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='detect_objects'. Required: paymentId, imageBase64, query.

e_signature(note, signers, paymentId, customerEmail, documentBase64)

Send a document out for legally binding e-signature and have the signed copy emailed back. Upload the PDF, name up to 3 signers, and give the email where the signed copy should land. Flat 1000 sats per document. The request is fulfilled through an established e-sign provider; the signed copy arrives by email once everyone has signed. Privacy: the PDF is processed in memory and never stored. Pay with Bitcoin Lightning — no account, no card. Requires create_payment with toolName='e_signature'. Required: paymentId, documentBase64, signers, customerEmail.

edit_image(prompt, paymentId, resolution, aspectRatio, imageBase64, outputFormat)

Edit an image with natural language instructions. Uses Nano Banana 2 — understands context, handles object addition/removal, style transfer, and inpainting. Returns JSON with image URL. Resolution-tiered pricing: 1K=200 sats, 2K=300 sats, 4K=450 sats. Pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='edit_image' and resolution param. Required: paymentId, prompt, imageBase64.

end_voice_bridge(sessionId)

Hang up a Voice Bridge call, finalize billing, and return a LNURL-withdraw refund link for unused deposit time. Also returns the final transcript for convenience. Required: sessionId.

epub_to_audiobook(speed, voice, modelId, fileName, language, paymentId, epubBase64, translateToLanguage, selectedChapterIndices)

Convert books (EPUB/PDF/TXT) to full audiobooks with automatic chapter detection, multi-voice narration, and optional translation to any language before narration. 3 voice tiers: OmniVoice Global (602+ langs, ~90 chars/sat), Inworld Premium (#1 ranked TTS ELO 1217, ~13 chars/sat), Minimax Studio (voice cloning from reference clip, ~7 chars/sat). Min 500 sats. Async — returns jobId, poll until completed (5-60+ min). Single payment, full outcome — no multi-step orchestration required. Pay with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='epub_to_audiobook'. Required: paymentId, epubBase64, fileName.

extract_document(modelId, paymentId, documentBase64)

Extract text from PDFs and images as clean Markdown. Uses Mistral OCR — handles complex layouts, tables, handwriting, multi-column documents, and mathematical notation. Preserves document hierarchy in structured Markdown. 10 sats/page. Pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='extract_document' and quantity=pageCount for multi-page PDFs. Required: paymentId, documentBase64.

extract_receipt(paymentId, documentBase64)

Extract structured data from receipts, invoices, and financial documents. Uses a dual-model pipeline (Mistral OCR + Kimi K3) for high-accuracy extraction. Returns JSON with merchant, date, line items, totals, tax, currency, and expense category. Handles crumpled receipts, faded text, and multi-page invoices. 25 sats/page. Pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='extract_receipt'. Required: paymentId, documentBase64.

generate_3d_model(prompt, modelId, paymentId, imageBase64)

Generate a textured 3D GLB model from EITHER a photo OR a text prompt (provide exactly one, not both). Uses Tencent Hunyuan3D — high-fidelity geometry and PBR materials. Async — returns requestId, poll with check_job_status. 1600 sats per model. Pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='generate_3d_model'. Required: paymentId.

generate_image(prompt, modelId, paymentId, aspectRatio, imageBase64)

Generate an image from a text prompt. Returns JSON with image URL. Models: Grok Imagine (fast creative generation, 100 sats), Seedream 4 (photorealistic detail, 150 sats), Nano Banana 2 (premium quality, 200 sats, default). Supports img2img with optional base64 input. Optional aspectRatio (default 1:1) works on every model tier and does not change the price. Stable endpoints — models upgrade automatically as SOTA evolves. Pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='generate_image'. Required: paymentId, prompt.

generate_music(lyrics, prompt, bitrate, modelId, paymentId, sample_rate, audio_format, is_instrumental, lyrics_optimizer)

Generate full songs (up to 6 min) with natural AI vocals, BPM/key control (99%+ accuracy), and 14+ section tags for precise arrangement. Uses Music-2.6 — orchestral and traditional instruments, style-aware mixing. Specify BPM, key, genre, mood in prompt. Returns MP3 URL. 500 sats per song. Pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='generate_music'. Required: paymentId, prompt.

generate_text(prompt, modelId, fileName, maxTokens, paymentId, fileContext, imageBase64, systemPrompt)

Generate text using frontier AI language models. Pure per-character pricing (no minimum): Kimi K3 (best, ~10 chars/sat, 1M context, vision support, default), GPT-OSS-120B (standard, ~1000 chars/sat, 119 languages, best value). Rates are BTC-pegged and re-quoted hourly, so treat them as approximate — the 402 challenge is the authoritative price. Supports document Q&A via fileContext and vision analysis via imageBase64 (best model). Stable endpoints — models upgrade automatically. Pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='generate_text' and the exact prompt. Required: paymentId, prompt.

generate_video(prompt, modelId, duration, paymentId, resolution, generate_audio)

Generate cinematic video from a text prompt. Uses ByteDance Seedance 2.0 — #1 on the Artificial Analysis text-to-video leaderboard — with synchronized native audio. Async — returns requestId, poll with check_job_status. 480p/720p/1080p, 4-15 seconds, priced per second by resolution (BTC-pegged; native audio free). Pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='generate_video' and duration, resolution params. Required: paymentId, prompt, duration.

get_cost_estimate(chars, model, pages, minutes, seconds, service)

Get an exact sat cost quote for a service BEFORE creating a payment. Useful for budget-aware agents to price-check before committing. No payment required, no side effects. Pass service=text-to-speech&chars=1500, service=translate&chars=800, service=transcribe-audio&minutes=5, etc. Returns { amount_sats, breakdown, currency }. Omit params to see the full catalog of supported services.

get_error_codes

Get the machine-readable catalog of all error codes this API can return (e.g. TIMEOUT, CONTENT_FILTERED, RATE_LIMITED, L402_REFUND_ISSUED, L402_AUTO_ROUTED). Agents should branch on error_code rather than parsing free-text messages. No payment required.

get_job_result(jobType, requestId)

Retrieve the final output of a completed async job. Call ONLY after check_job_status returns status='completed' — calling on a non-completed job returns an error. Returns JSON whose shape depends on jobType: video/video-image → { videoUrl, duration }; image-3d → { modelUrl } (GLB format); transcription → { text, language, segments }; epub-audiobook → { audioUrl, chapters }; ai-call → { transcript, duration, summary }. All URLs are temporary (valid ~1 hour) — download immediately. This tool is free and does not require payment. Do NOT use for synchronous tools — those return results directly. Required: requestId, jobType.

get_model_pricing(modelId)

Get pricing for a specific model by ID. No payment required. Required: modelId.

list_models(category)

Discover available AI models with numeric IDs, tier labels, capabilities, and per-call pricing in sats. Call this before create_payment to find the right modelId for your task. Returns JSON array: [{ id, name, tier, description, price, isDefault, category }]. Models marked isDefault=true are used when you omit modelId from create_payment. Filter by category to narrow results to a specific tool. This tool is free, requires no payment, and is idempotent — safe to call repeatedly.

list_planned_services

List all planned services with current vote counts. Returns JSON array: [{ slug, name, description, votes }], sorted by votes descending. No payment required — this is a free discovery tool. Use the slug values with vote_on_service to cast votes. This tool is idempotent and safe to call repeatedly.

merge_pdfs(files, paymentId)

Merge multiple PDF files into a single document. Preserves bookmarks, links, and formatting. Returns JSON: { url } — a temporary download URL (valid ~1 hour). Minimum 2 files, no maximum. Files are concatenated in array order. 100 sats per merge regardless of file count. Use convert_file instead if you need format conversion (e.g., DOCX→PDF). Pay per request with Bitcoin Lightning — no API key, no account needed. Requires create_payment with toolName='merge_pdfs'. Required: paymentId, files.

open_voice_bridge(codec, language, paymentId, sttEnabled, ttsEnabled, phoneNumber, refundAddress, durationMinutes)

TEMPORARILY UNAVAILABLE OVER MCP — create_payment refuses this tool, so you will not be charged. Use the L402 HTTP endpoint instead: POST https://sats4ai.com/api/l402/voice-bridge/open (same service and pricing, pay the 402 challenge), or use ai_call for a fully-managed agent call over MCP. Open a Voice Bridge session: a live phone call where YOUR LLM is the brain. Sats4AI provides PSTN + streaming STT + TTS as composable primitives. You decide when to speak (call voice_bridge_say), you read transcripts as they arrive (call poll_voice_bridge), you close the call when done (call end_voice_bridge). Unused deposit time is refunded via LNURL-withdraw. Use this when you want to keep your conversation context private and drive each turn yourself. When NOT to use: not for fully-managed agent-style calls where we handle the brain (use ai_call). Not for one-shot TTS broadcasts or IVR playback (use place_call). Not when live transcript polling adds no value — the per-turn overhead isn't worth it. Privacy: transcripts held in memory only, garbage-collected 30 minutes after the call ends; call audio is never persisted. Pay with Bitcoin Lightning — no telecom account, no signup. Requires create_payment with toolName='voice_bridge_open', phoneNumber, durationMinutes. Deposit is priced per destination off the carrier rate sheet and is BTC-pegged, so call create_payment for the exact figure; premium-rate and satellite ranges are refused. Required: paymentId, phoneNumber.

place_call(message, audioUrl, paymentId, phoneNumber, durationMinutes)

Bridge the digital-physical gap — place an automated phone call to deliver a spoken message or play audio to any number. Useful when your task requires notifying a human, delivering alerts, or reaching someone who isn't online. Pay with Bitcoin Lightning — no telecom account, no KYC, no subscription. Requires create_payment with toolName='place_call' and phoneNumber. Required: paymentId, phoneNumber.

poll_voice_bridge(cursor, sessionId)

Fetch new transcript events from an open Voice Bridge call since the last cursor. Returns partial + final transcripts + system events. Agent should poll in a loop (~500ms-1s). No additional payment. Required: sessionId.

receive_fax(ocr, email, paymentId, fromNumber, callback_id, callback_url)

When you're expecting a fax back — bank confirmation, court filing, signed document — open a 24h receive window at our shared number +1 320 299 1523. Matched by caller ID (last 10 digits of the sender), delivered to your email as soon as it arrives. Optional OCR add-on (+200 sats) returns a searchable text file alongside the PDF — useful for feeding the content to an agent or archiving. Optional callback_url POSTs an HMAC-signed webhook on delivery so your agent doesn't have to poll. No refund if no fax arrives within the window (prevents subscription squatting). If OCR fails, an LNURL-withdraw for 200 sats is included in the delivery email for partial refund. Pay with Bitcoin Lightning — no dedicated fax number rental, no monthly subscription, no account. Required: paymentId, email, fromNumber.

remove_background(paymentId, imageBase64)

Remove background from any image, returning transparent PNG. Uses BiRefNet (state-of-the-art, Papers with Code — Sm 0.901 on DIS5K). Handles hair, fur, glass, transparency, and complex edges. Stable endpoint — model upgrades automatically as SOTA evolves. 44 sats per image, pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='remove_background'. Required: paymentId, imageBase64.

remove_object(query, paymentId, imageBase64, box_threshold, text_threshold)

Remove unwanted objects from images by describing what to remove — no mask needed. Combines Grounding DINO detection (ECCV 2024) with Bria Eraser inpainting. Just say 'person', 'car', or 'watermark' and the object is erased and filled convincingly. 130 sats per image, pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='remove_object'. Required: paymentId, imageBase64, query.

request_refund(email, invoice, feedback, paymentId)

Open a MANUAL 48-hour refund review ticket for a service that FAILED (error, timeout, wrong output). Sends an email to the operator. DO NOT call this for unused-minute refunds on metered services (ai_call, voice_bridge) — those are returned automatically as an LNURL-withdraw link in the service's own response under `refund.lnurl_withdraw`, no manual ticket needed. If you call this on a metered payment that already has a pending LNURL refund, this tool will detect it and return the existing LNURL instead of creating a duplicate ticket. CLAIM WINDOW: refunds must be claimed within 30 days — after that the LNURL link stops working and the refund expires, so do not bank a link for later. Required: paymentId, invoice.

restore_face(upscale, fidelity, paymentId, imageBase64, face_upsample, background_enhance)

Restore blurry, damaged, or AI-generated faces to sharp, natural quality. Uses CodeFormer (NeurIPS 2022, state-of-the-art FID 32.65 on CelebA-Test). Adjustable fidelity — balance between quality enhancement and identity preservation. Also enhances background and upsamples. Stable endpoint — model upgrades automatically as SOTA evolves. 25 sats per image, pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='restore_face'. Required: paymentId, imageBase64.

send_email(to, body, replyTo, subject, paymentId)

Reach anyone with an email address — useful when your task requires formal communication, sending reports, or contacting someone outside chat. No SMTP server, no domain verification needed. Plain text, max 10,000 chars body, 200 chars subject. 200 sats. Pay with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='send_email'. Required: paymentId, to, subject, body.

send_fax(mode, text, pages, pdfUrl, coverText, paymentId, phoneNumber)

When your task requires a paper-trail on the other end — loan paperwork to a bank, signed contract to a notary, booking confirmation to a hotel in Japan — send a fax to any number worldwide. Two modes: 'pdf' (fetch from public URL) or 'text' (we format typed text into a PDF locally). Text/cover support Latin (incl. Central European, Vietnamese), Greek, Cyrillic, Japanese, Korean, Chinese (Simplified + Traditional), Thai, Hindi, Georgian, Armenian, Amharic; RTL scripts (Arabic/Hebrew) and emoji are rejected BEFORE your payment is consumed. Optional cover page. Pricing: 500 sats for up to 10 pages, +50 sats per additional page. Max 350 pages / 50 MB. Pass 'pages' to create_payment as 'quantity' to get the right invoice. Pay with Bitcoin Lightning — no fax machine, no phone line, no telecom account. Required: paymentId, phoneNumber, mode.

send_sms(message, paymentId, phoneNumber)

Reach a human via SMS when your task requires real-world coordination. Send to any phone number worldwide — messages delivered in seconds. No phone plan, no SIM card, no telecom account needed. Pay with Bitcoin Lightning — no API key, no KYC, no subscription. Requires create_payment with toolName='send_sms' and phoneNumber+message at payment time. The phoneNumber and message must match those used in create_payment. Required: paymentId, phoneNumber, message.

text_to_speech(text, speed, voice, modelId, language, paymentId, voice_description)

Text-to-speech with 3 tiers: OmniVoice Global (602+ languages including Yoruba, Bengali, Cebuano, Twi, zero-shot voice cloning, ~90 chars/sat — use 'language' parameter with ISO code), Inworld Premium (#1 ranked TTS ELO 1217, emotion control, 40+ languages, ~13 chars/sat), Minimax Studio (voice cloning from reference clip, 40+ languages, ~7 chars/sat). Adjustable speed (0.5-2.0x). Returns audio URL. Pay with Bitcoin Lightning — no API key or signup needed. When NOT to use: not for phone calls (use place_call for one-shot broadcasts, ai_call for AI voice agents, or open_voice_bridge to drive the call with your own LLM). For rare/underserved languages (Yoruba, Twi, Marathi, Cebuano, etc.), pick OmniVoice Global via language= — Inworld/Minimax don't cover these. Requires create_payment with toolName='text_to_speech'. Required: paymentId, text.

transcribe_audio(language, paymentId, audioBase64)

Transcribe audio to text with timestamps. Uses Mistral Transcription — high-accuracy speech recognition that handles accents, background noise, and overlapping speakers. 13 languages: en, zh, hi, es, ar, fr, pt, ru, de, ja, ko, it, nl. Up to 500 MB / 60 minutes per file. Async — returns requestId, poll with check_job_status(jobType='transcription'), then get_job_result. 10 sats/min. Privacy: audio and transcripts are ephemeral — processed, returned, and discarded. Never persisted. Pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='transcribe_audio'. Required: paymentId, audioBase64.

transcribe_translate(paymentId, audioBase64, sourceLanguage, targetLanguage)

Compound endpoint — one payment turns audio in any of 13 source languages into both a transcript AND a translation in any of 119 target languages. Perfect for WhatsApp voice messages in a language you don't speak (Yoruba → English), or recording a meeting in another language and reading it in yours. Auto-detects source if omitted. Async — returns requestId, poll with check_job_status(jobType='transcribe-translate'). Flat price covers STT + translation. Cheaper than calling transcribe_audio + translate_text separately for typical voice messages. Pay with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='transcribe_translate'. Required: paymentId, audioBase64, targetLanguage.

translate_rare_language(text, paymentId, targetLanguage)

Translate into 452 languages, 251 of them NOT supported by ChatGPT, Claude or Gemini (29 of those 251 measured at fair quality or better against human references) — including Bhojpuri (~50M speakers), Maithili (~34M), Egyptian Arabic (~100M), Moroccan Arabic (~30M), Chhattisgarhi, Magahi, Manipuri, Kashmiri, Shan, Kachin, Awadhi, Tamazight, Crimean Tatar, Quechua, Nuer, Sango, plus indigenous and minority languages with no callable API anywhere. Runs MADLAD-400 (Apache-2.0). QUALITY VARIES AND IS PUBLISHED PER LANGUAGE: every language carries a measured tier — good (chrF++ >= 45 vs human reference translations), fair (32-45), unverified (no benchmark exists, untested, may be poor), experimental (known weak). The response repeats the tier so you can judge how much to trust it. GET https://sats4ai.com/api/l402/translate-rare-language for the full language list with tiers, or GET /api/languages. Unsupported languages are rejected BEFORE payment. For mainstream languages use translate_text instead — it is cheaper and more fluent. Priced 50 sats base + 0.002 sats/char (GPU). Pay with Bitcoin Lightning — no API key or signup. Requires create_payment with toolName='translate_rare_language'. Required: paymentId, text, targetLanguage.

translate_text(text, modelId, paymentId, sourceLanguage, targetLanguage)

Translate text across 119 languages with high accuracy. Uses GPT-OSS 120B — top scorer in our multilingual translation evals with strong low-resource support. Auto-detects source language. Privacy-preserving: no data stored. Pricing: 1 sat per 1,000 characters, minimum 1 sat per request. Language parameters accept English names ('Spanish', 'Chinese (Simplified)') or ISO-639 codes / locale tags ('es', 'en-US', 'pt-BR', 'zh-Hans'). Supported languages: Afrikaans, Albanian, Amharic, Arabic, Armenian, Assamese, Azerbaijani, Basque, Belarusian, Bengali, Bosnian, Bulgarian, Burmese, Catalan, Cebuano, Chichewa, Chinese (Simplified), Chinese (Traditional), Corsican, Croatian, Czech, Danish, Dari, Dutch, English, Esperanto, Estonian, Farsi, Fijian, Filipino, Finnish, French, Frisian, Galician, Georgian, German, Greek, Guarani, Gujarati, Haitian Creole, Hausa, Hawaiian, Hebrew, Hindi, Hmong, Hungarian, Icelandic, Igbo, Indonesian, Irish, Italian, Japanese, Javanese, Kannada, Kazakh, Khmer, Kinyarwanda, Korean, Kurdish, Kyrgyz, Lao, Latvian, Lingala, Lithuanian, Luganda, Luxembourgish, Macedonian, Malagasy, Malay, Malayalam, Maltese, Maori, Marathi, Mongolian, Nepali, Norwegian, Occitan, Odia, Pashto, Polish, Portuguese, Punjabi, Romanian, Romansh, Russian, Samoan, Scots Gaelic, Serbian, Sesotho, Setswana, Shona, Sindhi, Sinhala, Slovak, Slovenian, Somali, Spanish, Sundanese, Swahili, Swedish, Tajik, Tamil, Tatar, Telugu, Thai, Tigrinya, Tongan, Turkish, Turkmen, Ukrainian, Urdu, Uzbek, Vietnamese, Welsh, Wolof, Xhosa, Yiddish, Yoruba, Zulu. Pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='translate_text' and prompt (the text to translate). Required: paymentId, text, targetLanguage.

upscale_image(scale, paymentId, imageBase64, face_enhance)

Upscale images 2x or 4x with neural super-resolution. Uses Real-ESRGAN (ICCV 2021, PSNR 32.73dB on Set5 4x, 100M+ production runs). Recovers real detail from low-resolution images — not interpolation. Optional face enhancement. Stable endpoint — model upgrades automatically as SOTA evolves. 5 sats per image, pay per request with Bitcoin Lightning — no API key or signup needed. Requires create_payment with toolName='upscale_image'. Required: paymentId, imageBase64.

voice_bridge_say(text, encoding, language, sessionId, audioBase64, voiceDescription)

Inject audio into an open Voice Bridge call. Two modes: (1) text — we synthesize via OmniVoice TTS in any of 602 languages; (2) audio_base64 + encoding — bring your own audio (mulaw_8000 or pcm_l16_16000 for MVP). STT is automatically muted while we inject, so the agent doesn't hear itself. No additional payment — covered by the session deposit. Required: sessionId.

vote_on_service(slug, paymentId)

Vote for a planned service to be built next. Returns JSON: { success, slug, newVoteCount }. 1 sat per vote — multiple votes allowed. Call list_planned_services first to discover valid slugs and current vote counts. Highest-voted services get prioritized. Requires create_payment with toolName='vote_on_service'. Required: paymentId, slug.

Last successful function declaration observed on 2026-08-13. Source: https://sats4ai.com/api/mcp. We list what the server declared; we do not call any of these functions.

Endpoint status observed on 2026-08-13. Source: https://sats4ai.com/api/mcp.

Signals

These are separate measurements of different things. They are deliberately not combined into one score, because a popularity number that mixes website traffic with saves and stars cannot be checked or acted on.

Where to get it

• Repository — https://github.com/cnghockey/sats4ai-mcp-server
• npm: sats4ai-mcp
• Remote endpoint (streamable-http) — https://sats4ai.com/api/mcp

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These share tags the maintainers applied themselves, such as bitcoin, l402, lightning-network, no-kyc. Common tags like "mcp" or "ai" are ignored for this: agreeing with six hundred other projects is not a similarity.

This is not a recommendation and not a test result. It is a map of what the authors said their work is about.

How the author describes it

Topics the maintainer set on GitHub: ai-agents, bitcoin, l402, lightning-network, mcp, micropayments, model-context-protocol, no-kyc, sms, text-to-speech.