2026 年真正最佳的文字轉語音 AI API 是哪個？

How We Ranked the Best Text to Speech AI APIs

This comparison separates three kinds of evidence:

1. Independent voice-preference data: Artificial Analysis’ blind Speech Arena.

2. Documented capabilities: model IDs, languages, streaming, cloning, limits, formats, and controls from official documentation.

3. Editorial judgment: which combination is most useful for a specific application.

The ranking framework gives the greatest importance to:

These weights are a decision framework, not a fabricated in-house benchmark. GPT Proto availability also does not influence the global ranking.

Best Text to Speech AI APIs at a Glance

Qwen Audio 3.0 TTS Plus: Best Current Signal for Raw Voice Quality

Qwen Audio 3.0 TTS Plus is the clearest answer if your first question is: “Which provider voice currently wins more blind listening comparisons?”

It sits at the top of Artificial Analysis’ provider-voice leaderboard. The gap over the nearest models is narrow, so it should be read as a strong current signal—not proof that every Qwen voice will beat every rival on every language or script. Qwen Audio 3.0 TTS Plus analysis

The API supports natural-language instructions for tone, speed, emotion, and timbre. It also accepts inline tags such as [sad], [excited], and [trembling], plus non-verbal effects. Voice cloning and real-time synthesis are available. Alibaba Cloud Qwen Audio TTS guide

There are two practical costs:

• Independent analysis shows lower throughput than several real-time-focused rivals.

• The international and China deployments have regional keys and rate limits; the current documented job-submission limit for Qwen Audio TTS is three requests per second.

Verdict: Pick Qwen Audio 3.0 TTS Plus for narration, ads, character lines, and other prerecorded audio where final delivery matters more than instant playback. It is not my first choice for a latency-sensitive phone agent.

Cartesia Sonic 3.5: Best for Real-Time Voice Agents

Cartesia has a narrower proposition: make speech start quickly and remain stable during conversation.

Sonic 3.5 supports 42 languages and advertises sub-90 ms model latency. It also provides streaming, pronunciation controls, voice cloning, and adjustments for emotion, speed, and volume. Cartesia Sonic 3.5 documentation

Its WebSocket workflow can accept text fragments as an LLM produces them, while preserving context across those fragments. That is important for agents: waiting for an LLM to finish a full paragraph before beginning TTS makes even a fast voice model feel slow. Cartesia real-time TTS quickstart

Sonic 3.5 also sits near the top of the current provider-voice leaderboard, with an Elo score around 1,209. Artificial Analysis Sonic 3.5

The trade-off is product fit. Cartesia is excellent infrastructure for phone agents, tutors, game characters, and interactive assistants. It is less of an all-in-one creator environment for manually producing and editing an audiobook.

Verdict: Choose Sonic 3.5 when a 300 ms pause feels like a product bug.

Gemini 3.1 Flash TTS: Best for Controllable Multi-Speaker Audio

Gemini 3.1 Flash TTS is the most interesting choice for podcasts, interviews, lessons, and scripted character conversations.

The Gemini TTS API can generate single-speaker or multi-speaker audio. Instead of exposing only numeric sliders, it accepts natural-language directions for accent, style, pace, and tone. Gemini 3.1 also adds expressive audio tags for more precise delivery. Google speech generation guide

Its current Speech Arena Elo is around 1,211, placing it among the leading provider voices. Artificial Analysis Gemini 3.1 Flash TTS

The problem is the word “Preview.” Google explicitly notes that preview models may change before becoming stable and can have tighter rate limits. The standard price is currently $1 per million text input tokens and $20 per million audio output tokens; Google documents audio generation at 25 audio tokens per second. That works out to roughly $1.80 per finished audio hour for the output component, before input, retries, or surrounding infrastructure. Gemini API pricing

Verdict: Choose Gemini 3.1 Flash TTS for controlled two-person dialogue and prompt-directed narration. Do not treat Preview status as equivalent to a mature, frozen production model.

Inworld Realtime TTS-2: Best for Multilingual Real-Time Applications

Inworld Realtime TTS-2 combines real-time generation with unusually broad language and locale coverage.

The official documentation lists natural-language steering, more than 200 languages and locales, instant voice cloning, and timestamp output containing phonetic detail and visemes. Those timestamps are useful for lip-sync, avatars, highlighting spoken words, and language-learning interfaces. Inworld TTS models

Inworld lists approximately 200 ms median latency for TTS-2. The product family also includes TTS 1.5 Max for stability and TTS 1.5 Mini for lower latency. Previous inworld-tts-1 model names were discontinued in June 2026 and now route to their 1.5 successors.

The cost of this flexibility is naming complexity. TTS-2, 1.5 Max, and 1.5 Mini are not interchangeable labels for the same service. Teams should select one deliberately and pin the model ID.

Verdict: Choose Inworld when multilingual coverage, cloning, timestamps, and interactive delivery belong in the same application.

ElevenLabs API: Best Voice and Creator Ecosystem

ElevenLabs is not the current number-one provider voice in every independent comparison. It still has one of the most complete voice products around its API.

Developers can choose among:

• Eleven v3: expressive speech, dialogue, and more than 70 languages.

• Multilingual v2: stable long-form narration across 29 languages.

• Flash v2.5: roughly 75 ms model latency, 32 languages, and a larger character limit.

ElevenLabs TTS model comparison

The same ecosystem includes a voice library, instant and professional cloning, voice design, dubbing, creator tools, pronunciation control, and Text to Dialogue. That reduces the amount of voice-management infrastructure a product team must build itself.

The trade-off is cost and choice. A team can select the wrong ElevenLabs model simply because the model names all sit under the same brand. High-expression narration, consistent long-form output, and fast agent speech should not automatically use the same route.

Verdict: Choose ElevenLabs when the surrounding voice ecosystem matters almost as much as the synthesis model.

Fish Audio S2.1 Pro Free: Best Free TTS API for Prototyping

Fish Audio offers one of the clearest answers to free AI text to speech API.

The s2.1-pro-free model uses the same TTS endpoint and underlying model as s2.1-pro, but costs $0 for testing, prototyping, development, and smaller projects. The limitation is explicit: the free route does not include the same time-to-first-audio or data-processing guarantees as the production route. Fish Audio TTS documentation

The S2 family supports HTTP and WebSocket generation, cloning, multi-speaker workflows, and inline expression cues. Fish Audio documents more than 64 emotional expressions and voice styles. Fish Audio emotion controls

This is what a useful free tier should look like: good enough to determine whether the model fits your application, with a clearly stated production trade-off.

Verdict: Use S2.1 Pro Free to build a prototype. Move to a guaranteed production route before promising latency or capacity to paying users.

MiniMax Speech 2.8 HD: Best for Long-Form Speech and Voice Cloning

MiniMax Speech 2.8 HD is the current fidelity-focused MiniMax model. Speech 2.8 Turbo is its faster sibling.

Both support 40 languages, seven named emotions, dialect controls, streaming, and voice workflows. The 2.8 models also accept interjection tags such as laughs, sighs, gasps, coughs, and breaths. Requests support up to 10,000 characters, while MiniMax recommends streaming for text above 3,000 characters. MiniMax TTS API reference

The published pay-as-you-go rate is $100 per million characters for Speech 2.8 HD and $60 per million characters for Speech 2.8 Turbo. Rapid voice cloning is separately priced. MiniMax pay-as-you-go pricing

One version detail matters: Speech 2.6 and Speech 02 now appear under MiniMax’s Legacy Models. They remain callable, but they should not be presented as the company’s newest TTS generation. MiniMax model list

Verdict: Choose Speech 2.8 HD for audiobooks, narration, multilingual publishing, and cloned voices. Choose Turbo when response time and cost matter more than the last increment of fidelity.

GPT-4o Mini TTS: Best for Existing OpenAI Workflows

GPT-4o Mini TTS is the easy choice when your application already uses OpenAI’s SDK, authentication, monitoring, and speech endpoint.

It supports natural-language instructions for accent, emotional range, intonation, speed, tone, and whispering. The Speech API streams audio and supports MP3, Opus, AAC, FLAC, WAV, and PCM output. OpenAI text-to-speech guide

The current documentation lists 13 built-in voices, including marin and cedar, which OpenAI recommends for quality. Voices are optimized primarily for English, although the model can generate multiple languages.

OpenAI now also documents custom voices for eligible customers. Creating one requires both a consent recording and a matching sample recording. This is not a generally available self-service cloning market in the same sense as ElevenLabs or MiniMax.

OpenAI requires applications to tell end users that the voice is AI-generated.

Verdict: Start here when adding another provider would create more engineering work than voice improvement. Test another API if cloning, preset-voice variety, or top independent voice preference is the central product requirement.

Why Some Famous Speech APIs Did Not Rank Higher

Microsoft Azure Speech and Amazon Polly remain sensible choices for teams already committed to their cloud infrastructure, regional deployment, SSML, identity management, and enterprise procurement.

They are not bad APIs. They simply solve a different decision problem than “Which new TTS model currently produces the most preferred voice?”

CapCut, TikTok, Speechify, NaturalReader, and Descript were also excluded from the main ranking because they are primarily creator or reading products. Some expose developer services, but their consumer interfaces should not be confused with a bottom-layer TTS API comparison.

Speech-to-text APIs were excluded because they perform the reverse task.

Which TTS API Should You Choose?

Is There a Truly Free Text to Speech AI API?

There are free TTS APIs, but “free” can mean five different things:

• A temporary credit

• A monthly free quota

• A free developer model without latency guarantees

• A free personal tool without commercial rights

• Open model weights that require your own GPU infrastructure

Fish Audio’s s2.1-pro-free is a real free developer route, but it does not promise production TTFA or DPA guarantees.

Google currently offers free-tier access to Gemini 3.1 Flash TTS, but rate limits and data-handling conditions differ from paid usage.

A free API is evidence that you can test a model. It is not evidence that commercial rights, guaranteed capacity, support, and production traffic will remain free.

How Much Does a TTS API Really Cost?

Do not compare a per-character price with a per-token price as if they were the same unit.

Use this formula:

Total speech cost =
input text cost
+ generated audio cost
+ failed and repeated generations
+ voice cloning or design fees
+ storage and delivery costs

For character-priced APIs:

Estimated generation cost =
total characters ÷ 1,000,000 × price per 1M characters

For audio-token pricing:

Estimated output cost =
audio seconds × audio tokens per second
÷ 1,000,000
× price per 1M audio tokens

Examples of current public pricing signals include:

Run the same production-length script several times. One cheap generation is irrelevant if pronunciation errors force three regenerations.

Run the Same TTS Test Across Different APIs

Test 1: Names, Dates and Numbers

At 8:05 a.m. on September 18, 2026, Dr. Siobhán Nguyen approved invoice GX-407 for $1,284.50.

Please call plus one, four one five, five five five, zero one three seven, or visit api dot aster dash labs dot io slash v three before 6:30 p.m.

Test:

• The pronunciation of “Siobhán”

• Letter-number grouping in GX-407

• Date and time rhythm

• Dollar amount accuracy

• Phone-number grouping

• URL handling

For production, spell out ambiguous symbols when accuracy matters more than visual fidelity to the original text.

Test 2: Emotion and Pacing

Keep your voice low at first.

The room is empty... or at least, it should be.

Wait—did you hear that?

Don’t move. Slowly, very slowly, look behind you.

Performance direction: Begin quietly and cautiously. Pause after “should be.” Shift to sudden alertness on “Wait,” then slow the final sentence without shouting.

Do not paste one provider’s control tags into every API:

• Qwen accepts its own bracketed emotional tags.

• MiniMax Speech 2.8 supports parenthetical interjections.

• Fish Audio S2 uses bracketed expression cues.

• Gemini and GPT-4o Mini TTS accept natural-language direction.

• ElevenLabs control varies by model.

The spoken text can remain constant. The control layer should be adapted to the provider.

How to Generate Speech Through an AI TTS API

The following example uses GPT-4o Mini TTS through GPT Proto.

Step 1: Store the API Key Safely

export GPTPROTO_API_KEY="your_api_key"

Do not commit the key to a public repository or place it in browser-side JavaScript.

Step 2: Send a cURL Request

curl -X POST "https://gptproto.com/v1/audio/speech" \
  -H "Authorization: $GPTPROTO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-4o-mini-tts",
    "input": "The first test confirms that our text to speech connection is working.",
    "voice": "alloy"
  }'

Step 3: Send the Same Request With Python

import os
import requests

url = "https://gptproto.com/v1/audio/speech"

headers = {
    "Authorization": os.environ["GPTPROTO_API_KEY"],
    "Content-Type": "application/json",
}

payload = {
    "model": "gpt-4o-mini-tts",
    "input": "The first test confirms that our text to speech connection is working.",
    "voice": "alloy",
}

response = requests.post(url, headers=headers, json=payload, timeout=120)
response.raise_for_status()

print(response.json())

Step 4: Send It With JavaScript

const response = await fetch("https://gptproto.com/v1/audio/speech", {
  method: "POST",
  headers: {
    Authorization: process.env.GPTPROTO_API_KEY,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    model: "gpt-4o-mini-tts",
    input:
      "The first test confirms that our text to speech connection is working.",
    voice: "alloy",
  }),
});

if (!response.ok) {
  throw new Error(`TTS request failed: ${response.status}`);
}

const result = await response.json();
console.log(result);

The GPT Proto-format documentation currently shows a JSON response workflow. Do not blindly copy code written for OpenAI’s direct binary audio response without checking the returned content type and response object.

Step 5: Do Not Assume Every TTS Model Uses the Same Payload

One GPT Proto key and balance can cover multiple models, but heterogeneous audio APIs may still use different routes and parameters.

For example:

A clean application should place these differences behind an internal adapter. “One account” is real. “Every audio model changes with one model string” is not universally true.

TTS Models Currently Available Through GPT Proto

As of July 22, 2026, relevant GPT Proto listings include:

• GPT-4o Mini TTS

• Gemini 2.5 Pro Preview TTS

• Gemini 2.5 Flash Preview TTS

• MiniMax Speech 2.6 HD

• MiniMax Speech 02 Turbo

Version context matters:

• Gemini 3.1 Flash TTS is newer than the Gemini 2.5 TTS models currently listed on GPT Proto.

• MiniMax Speech 2.8 is newer than Speech 2.6 and Speech 02.

• Speech 2.6 and Speech 02 remain useful for existing workflows, compatibility, or platform pricing, but they are not MiniMax’s latest models.

Text to Speech vs Speech to Text API

The names are easy to reverse:

Queries such as speech to text AI API and API AI speech to text belong to transcription, not this TTS comparison.