Ernie

Ernie (文心, Wenxin) is a family of large language models developed by Baidu, with origins in the 2019 ERNIE pre-trained encoder and current generations including ERNIE 4.5, ERNIE X1 (a reasoning-specialized variant), and the open-source ERNIE 4.5 series released under Apache 2.0 in mid-2025. The closed-weights variants power Baidu's consumer Ernie Bot chatbot, the company's enterprise AI products, and integrations across Baidu Search and Baidu Cloud's Qianfan platform; the open-weights ERNIE 4.5 family is distributed through Hugging Face, GitHub, and Baidu AI Studio. As of April 2026, Ernie is one of the principal Chinese frontier-model lines, with particular strength on Chinese-language benchmarks and a hybrid distribution posture that combines large-scale CAC-approved consumer deployment with open-weights commercial release.

At a glance

• Lab: Baidu
• Released: ERNIE 1.0 (2019); ERNIE 3.0 Titan (2021); ERNIE Bot launch with ERNIE 3.5 (March 2023, public access August 2023); ERNIE 4.0 (October 2023); ERNIE 4.5 and ERNIE X1 (March 16, 2025); ERNIE 4.5 open-source release (June 30, 2025); ERNIE X1.1 (September 2025)
• Modality: Text and multimodal (text, vision, with audio support in some variants)
• Open weights: Mixed. ERNIE 4.5 open-source family released under Apache 2.0 on June 30, 2025, available on Hugging Face, GitHub, and Baidu AI Studio. ERNIE X1 reasoning model and the production ERNIE 4.0 / 4.5 Turbo variants used in Ernie Bot remain closed-weights with API-only access.
• Context window: Up to 128,000 tokens for ERNIE 4.5; varies across variants
• Pricing: Approximately $0.55 per million input tokens for ERNIE 4.5 via Baidu Cloud Qianfan (substantially lower for ERNIE 4.5 Turbo); ERNIE Bot is free for consumer use after Baidu's March 2025 elimination of subscription fees ahead of schedule
• Distribution channels: Ernie Bot consumer chat, Baidu AI Cloud Qianfan platform for enterprise API, PaddlePaddle/ERNIE on GitHub, baidu organization on Hugging Face for open-source variants, integration into Baidu Search and Baidu Maps

Origins

ERNIE (Enhanced Representation through kNowledge IntEgration) began in 2019 as a pre-trained language encoder structurally similar to Google's BERT but with a knowledge-graph-aware training objective that incorporated entity-level and phrase-level masking. ERNIE 2.0, released later in 2019, was the first language model to score above 90 on the GLUE benchmark, an early international visibility moment for the line.

ERNIE 3.0 in 2021 scaled the architecture substantially. ERNIE 3.0 Titan, a 260-billion-parameter dense model trained on a 4-terabyte multilingual corpus, was the largest Chinese-language model publicly disclosed at its release.

The conversational direction came with ERNIE Bot. Baidu announced the consumer chatbot on March 16, 2023, as one of the first major Chinese answers to ChatGPT's November 2022 launch. ERNIE Bot opened to invited testing on the same day and received Cyberspace Administration of China (CAC) approval for general public availability on August 31, 2023, alongside several other approved Chinese chatbots from Alibaba, Tencent, and Sensetime.

ERNIE 3.5 (June 2023) and ERNIE 4.0 (October 2023) were the two main generations during ERNIE Bot's first year. ERNIE 4.0 was unveiled at the Baidu World 2023 conference and made available to paid subscribers in November. ERNIE 4.0 Turbo, a faster and lower-cost variant, followed in June 2024.

The most consequential model-family changes came in 2025. On March 16, 2025, Baidu released ERNIE 4.5 and ERNIE X1, a deep-thinking reasoning model. The launch was paired with a pricing change: ERNIE Bot was made free to all consumers ahead of schedule, removing the prior subscription paywall. The pricing move was widely characterized as a response to DeepSeek-R1's January 2025 release.

The most strategically distinctive release came on June 30, 2025, with the open-source release of the ERNIE 4.5 family under Apache 2.0. The release included 10 variants spanning a 0.3-billion-parameter dense model up to a 424-billion-parameter mixture-of-experts model with 47 billion active parameters, plus multimodal vision-language variants. The move to permissive open-weights licensing for the production-tier ERNIE 4.5 family aligned Baidu with the open-weights posture taken by DeepSeek and Alibaba Qwen. ERNIE X1.1, the next reasoning-model iteration, followed in September 2025.

Capabilities

The Ernie family covers general-purpose text, multimodal text-and-vision, and dedicated reasoning across distinct variants.

ERNIE 4.5 is the production text-generation flagship. The largest open-source variant uses a mixture-of-experts architecture with 424 billion total parameters and 47 billion active per token; smaller variants scale down to a 0.3-billion-parameter dense model. The MoE architecture uses a heterogeneous modality structure with parameter sharing across modalities and dedicated parameters per modality, supporting multimodal understanding while preserving text-task performance. Training spans 5.6 trillion tokens across Chinese and English, with deeper Chinese coverage than typical English-centric open-weights peers.

The flagship handles general text generation, multi-turn dialogue, document analysis, code generation, and instruction following. Chinese-language performance is the line's strongest axis: on C-Eval and CMMLU, ERNIE 4.5 reaches scores in the high 80s, ahead of GPT-4o-class models. On English-language benchmarks, ERNIE 4.5 is competitive with mid-tier closed-weights frontier models but does not consistently lead.

ERNIE X1 is a reasoning-specialized model released alongside ERNIE 4.5 in March 2025. The model uses a chain-of-thought architecture with FlashMask dynamic attention masking that produces structured reasoning traces for complex mathematics, coding, and logic tasks. Baidu's positioning is as a Chinese counterpart to OpenAI's o-series and DeepSeek-R1, reporting performance on par with DeepSeek R1 at approximately half the API cost. ERNIE X1.1 in September 2025 reported a 34.8% factual-accuracy improvement and stronger agentic capabilities.

The multimodal vision-language variants include ERNIE-4.5-VL-28B-A3B-Thinking, a compact MoE model with approximately 30 billion total parameters and 3 billion active per token, designed for multimodal reasoning at consumer-deployable scale. The variants handle image understanding, document OCR, chart analysis, and visual question answering.

Production deployment is heavily integrated with Baidu's product surface: Ernie Bot, Baidu Search's AI features, and enterprise integrations through Baidu AI Cloud Qianfan. The closed-weights ERNIE 4.5 Turbo and ERNIE X1 Turbo variants released in April 2025 cover cost-sensitive production deployments where the flagship's compute cost is impractical.

Benchmarks and standing

The Ernie family's benchmark profile is strongest on Chinese-language and multimodal axes, with English-language performance competitive but not consistently leading.

On Chinese-language benchmarks, ERNIE 4.5 leads or matches GPT-4o-class models. C-Eval scores for ERNIE 4.5 reach approximately 88 to 92, ahead of GPT-4.5's reported 80 to 90 on the same evaluation. CMMLU scores are in the high 80s, similarly leading GPT-4o on Chinese-domain tasks. Baidu has emphasized these Chinese-language results as the line's distinctive position and the basis for the model's deployment in CAC-approved Chinese consumer products.

On English-language general-knowledge benchmarks, ERNIE 4.5 is competitive but does not lead. MMLU-Pro scores reach approximately 78, slightly below GPT-4.5 at 79 and trailing the leading frontier closed-weights releases. On MMMU, the multimodal benchmark, ERNIE 4.5 surpasses GPT-4o per Baidu's reported scores.

On mathematics, ERNIE 4.5 reports 94.1 on GSM8K, ahead of GPT-4.5 and DeepSeek-V3 on the same evaluation. The reasoning-specialized ERNIE X1 has not been publicly benchmarked at the granularity of GPQA Diamond or AIME 2025, with Baidu's positioning resting on the comparative claim of parity with DeepSeek R1 at lower cost.

The Artificial Analysis Intelligence Index has not consistently published Ernie scores at the cadence of US frontier-lab and DeepSeek releases, in part reflecting the Chinese-language and Chinese-product focus of the line. On LMArena, ERNIE 4.5 has appeared at competitive positions in the upper-middle tier of frontier models but has not held top positions through the 2025 release cycle.

The June 2025 open-source release of ERNIE 4.5 under Apache 2.0 has shifted the line's standing in the open-weights tier. ERNIE-4.5-21B-A3B reportedly outperforms Qwen3-30B-A3B on math and reasoning despite roughly 30% fewer parameters, positioning the Ernie open-weights variants as competitive within the Chinese open-weights ecosystem.

Benchmark leadership is point-in-time and the Chinese frontier-model space has rotated rapidly through 2025. Ernie's positions are representative of the March to June 2025 release period.

Access and pricing

Ernie distribution combines Baidu's first-party consumer and enterprise products with the open-source release.

The consumer Ernie Bot at yiyan.baidu.com provides free public access to ERNIE 4.5 and successor models. Free access began on March 16, 2025, ahead of the previously scheduled paid-tier transition, and follows Baidu's CAC-approved consumer LLM deployment posture.

Enterprise API access runs through the Baidu AI Cloud Qianfan platform, a model-as-a-service interface that hosts Ernie variants alongside third-party models. Per-token pricing for ERNIE 4.5 is approximately $0.55 per million input tokens, with ERNIE 4.5 Turbo and ERNIE X1 Turbo offered at substantially lower prices. The pricing positioning is approximately 1% of GPT-4.5's reported per-token rates and 50% of DeepSeek-V3 at the time of comparable launches, reflecting both Baidu's strategic emphasis on cost-competitiveness and the broader Chinese-LLM price compression of late 2024 and 2025.

The open-source ERNIE 4.5 family is distributed through the baidu organization on Hugging Face, PaddlePaddle/ERNIE on GitHub, and Baidu AI Studio. All open-source variants are released under Apache 2.0 with no use restrictions beyond the standard license terms. The ERNIE 4.5 GitHub repository also includes the ERNIEKit industrial-grade development toolkit.

The closed-weights ERNIE X1 reasoning model and the production Turbo variants used in Ernie Bot are not part of the open-source release and are accessible only through the Qianfan API and Ernie Bot product surface.

Comparison

Direct competitors to the Ernie family across the 2024 to 2025 active period:

• DeepSeek V3 and DeepSeek V4 (DeepSeek). The principal Chinese open-weights peer at the frontier tier. DeepSeek V3's December 2024 release established the open-weights cost-efficiency narrative that ERNIE 4.5's June 2025 open-source release partially responded to. DeepSeek leads on aggregate English-language benchmarks; Ernie's distinguishing position is Chinese-language depth and the Baidu product-distribution moat.
• Qwen 3 (Alibaba Qwen). The other major Chinese open-weights frontier line. Qwen 3's variant breadth and multimodal coverage exceed Ernie's at the open-weights tier. ERNIE 4.5 variants are reported to outperform some Qwen 3 sizes on math and reasoning at lower active-parameter counts; Qwen 3's earlier open-source posture has produced wider community adoption.
• Hunyuan (Tencent). Tencent's parallel Chinese frontier line. Hunyuan and Ernie are direct domestic competitors; both have moved toward open-weights releases in 2025 and 2026. Ernie's advantage has been Baidu Search integration; Hunyuan's advantage has been WeChat distribution.
• GPT-4o and GPT-5 (OpenAI). US closed-weights frontier comparators. ERNIE 4.5 is reported to lead GPT-4o on Chinese-language benchmarks (C-Eval, CMMLU) and on multimodal MMMU; GPT-4o and successors retain leads on English generalization and reasoning. The two are not directly comparable on market deployment given Chinese and US regulatory rules.
• Doubao (ByteDance). The fourth major Chinese consumer LLM. Doubao surpassed Ernie Bot in Chinese monthly active users through 2025 and into 2026, becoming the most-used native Chinese LLM consumer app. Ernie's positioning relative to Doubao is on Baidu Search integration and the open-source release strategy that Doubao has not matched.

Ernie's distinctive position: deep integration with Baidu Search and the broader Baidu product surface, leading Chinese-language benchmark scores, the open-source ERNIE 4.5 release under Apache 2.0, and CAC-approved consumer deployment with free public access.

Outlook

Open questions for Ernie over the next 6 to 18 months:

• ERNIE 5.0. Baidu announced in February 2025 that ERNIE 5.0 was in development, with an expected release across 2025 to 2026. Technical scope and licensing posture will determine whether the line continues the open-source direction.
• Open-source release cadence. Whether subsequent generations and reasoning-specialized variants (ERNIE X1.1, X2) follow open-source release patterns or remain closed will materially affect the line's standing in the open-weights ecosystem.
• Consumer market position vs. Doubao. Ernie Bot has been displaced by Doubao as the most-used Chinese consumer LLM. Whether Ernie Bot's distribution position recovers, particularly with Baidu Search integration providing distinctive value beyond pure conversational AI, is a strategic question.
• English-language and international expansion. Ernie's English-language performance trails the line's Chinese strength. Whether subsequent generations close the gap, and whether Baidu pursues international consumer deployment, will affect competitive standing outside China.
• Reasoning-model positioning. ERNIE X1.1 and successors will be evaluated against DeepSeek R1's continued evolution and against reasoning components integrated into GPT-5 and successors.

Sources

• ERNIE Blog: Announcing the Open Source Release of the ERNIE 4.5 Model Family. Official open-source release announcement, June 30, 2025.
• Hugging Face: baidu organization. Open-source ERNIE 4.5 model weights, model cards, and variant documentation.
• GitHub: PaddlePaddle/ERNIE. Official open-source repository with ERNIEKit development toolkit.
• Baidu: ERNIE 4.5 and ERNIE X1 Launch Press Release. March 2025 launch announcement and free Ernie Bot access.
• Wikipedia: Ernie Bot. Product history, release dates, user numbers, and CAC approval timeline.
• DataCamp: Baidu's ERNIE 4.5 and X1 Features and Comparison. Independent analysis of ERNIE 4.5 and X1 capabilities, pricing, and DeepSeek comparison.
• TechNode: Baidu Open-Sources ERNIE 4.5 Series Models. Coverage of the open-source release and the heterogeneous-modality MoE architecture.
• VentureBeat: Baidu's New Ernie-4.5 Open for Enterprise Use with Apache 2.0. Enterprise-focused coverage of the Apache 2.0 release.
• LifeArchitect: Baidu ERNIE. Comprehensive timeline of ERNIE generations from 2019 through 2025.