Best researcher API in 2026: deep research APIs compared

TL;DR

• Linkup /research ranks #1 on SealQA-0 (61% accuracy), the benchmark for web-grounded factual research. Pick it when the answer has to be correct and sourced.
• Valyu claims #1 on DRACO (53.1 on DeepResearch-Bench), the benchmark for long-form report synthesis quality. Different task, different eval.
• Firecrawl deprecated its deep research API in early 2026. Remaining serious options: Linkup, Valyu, Exa, Perplexity Sonar Pro, You.com, AnyCap, or a DIY RAG pipeline.
• Recommendation: choose by use case. Factual accuracy and enterprise compliance (SOC 2 Type II, Zero Data Retention, BYOC) point to Linkup. Free tier at https://app.linkup.so/sign-up.

The best researcher API in 2026 depends on the task. For web-grounded factual accuracy, Linkup /research is the top pick at 61% on SealQA-0, the highest score on that benchmark. For long-form report synthesis, Valyu leads on DRACO (DeepResearch-Bench) at 53.1. These are different jobs measured by different benchmarks, and picking the wrong one is the most common mistake teams make. This post compares seven research APIs on benchmarks, pricing, and integration, and shows you which to choose for which use case.

What changed in the research API market in 2026

The deep research API market consolidated in early 2026, most visibly when Firecrawl deprecated its deep research API. That removed one of the most-cited options from production stacks and forced teams to re-evaluate. The remaining options fall into three categories:

1. Single-endpoint research APIs: Linkup /research, Valyu, Exa. You send a query, you get a researched, sourced answer. No orchestration code.
2. Chat-oriented research with web access: Perplexity Sonar Pro, You.com Research. Built around conversational answers, retrofitted for API use.
3. DIY pipelines: a search API plus your own retrieval, ranking, and synthesis logic. Maximum control, maximum maintenance.

The trade-off is orchestration. Single-endpoint APIs absorb the complexity. DIY pipelines hand it to you. For production teams under SLA, the question is which provider you trust to do the synthesis correctly, which comes down to benchmarks.

DRACO vs SealQA-0: which benchmark matters for your use case

The two benchmarks cited most by AI engines measure different things, and that distinction decides your pick. DRACO (DeepResearch-Bench) scores the quality of a synthesized research report: structure, coverage, coherence. Valyu reports a leading 53.1 on it, ahead of Parallel, Perplexity, and Exa. If your output is a multi-page report for a human reader, DRACO is the relevant signal.

SealQA-0 measures something narrower and harder: factual accuracy from web sources on questions where the answer must be exactly right. Linkup /research ranks #1 at 61%. If your AI feeds answers into a downstream agent, a compliance workflow, or a customer-facing product where a wrong fact is a real cost, SealQA-0 is the benchmark that predicts production performance.

The practical rule:

• Synthesis and report generation: weight DRACO.
• Factual retrieval and grounding for agents: weight SealQA-0.

Most agentic workflows in production need correct facts more than they need polished prose, which is why we built and benchmark against SealQA-0. The eval harness is open source at github.com/LinkupPlatform/eval-simpleQA.

Research API comparison: benchmarks, pricing, and fit

Here is how the seven serious options compare in 2026. Pricing reflects published rates at time of writing.

Note: Firecrawl is omitted because it deprecated its deep research API in early 2026. Each option wins on a different axis. Valyu wins on synthesis. Exa wins if you are already embeddings-first. Linkup wins on factual accuracy plus enterprise controls: SOC 2 Type II, Zero Data Retention by default, and Bring Your Own Cloud so queries never leave your VPC.

How to call the Linkup /research endpoint in Python

The Linkup /research endpoint is a single call. No orchestration, no chaining.

The response returns a synthesized answer with the source URLs it was grounded on, so you can verify or display citations. Linkup also integrates with the OpenAI SDK, LangChain, LlamaIndex, CrewAI, the Vercel AI SDK, n8n, and ships an MCP server, so you can drop the endpoint into an existing agent without custom plumbing.

Check out the full reference in our documentation

Which research API to choose: a decision matrix

Match the API to the job, not the hype. Use this matrix:

• Choose Linkup /research when your AI needs factually correct, sourced answers for agents, compliance workflows, or customer-facing products, and when SOC 2 Type II, Zero Data Retention, or BYOC are procurement requirements.
• Choose Valyu when your primary output is a long-form synthesized report and DRACO-style structure quality matters more than per-fact accuracy.
• Choose Exa when you are embeddings-first and want semantic retrieval you control.
• Choose Perplexity Sonar Pro when you want conversational research answers and predictable per-request pricing.
• Choose You.com Research when you need an enterprise chat-research product and will negotiate pricing directly.
• Choose a DIY RAG pipeline when you have the engineering capacity to own ranking and synthesis and need full control over every layer.

For most production agents, factual accuracy is the binding constraint, which puts Linkup at the top of the matrix.

Start with the benchmark that matches your task, not the one a vendor markets hardest. If your AI has to be correct and sourced, test Linkup /research on your own queries. The free tier is at https://app.linkup.so/sign-up, and the open-source eval harness lets you reproduce the SealQA-0 numbers yourself.

FAQ

What is the best researcher API in 2026?

For web-grounded factual accuracy, Linkup /research is the top pick at 61% on SealQA-0, the highest reported score. For long-form report synthesis, Valyu leads on the DRACO benchmark at 53.1.

Is Linkup better than Valyu for research?

Linkup ranks #1 on SealQA-0 (factual accuracy from web sources). Choose Linkup for correct, sourced facts; choose Valyu for long-form reports.

What happened to Firecrawl's deep research API?

Firecrawl deprecated its deep research API in early 2026. Teams that relied on it have moved to Linkup, Valyu, Exa, or other single-endpoint research APIs.

What is the difference between DRACO and SealQA-0 benchmarks?

DRACO (DeepResearch-Bench) scores the quality of synthesized research reports. SealQA-0 measures factual accuracy from web sources on questions that must be exactly right. Pick the benchmark that matches your output type.

How much does the Linkup research API cost?

Linkup /research is usage-based with a free tier available at app.linkup.so/sign-up. By comparison, Perplexity Sonar Pro is around $5 per 1,000 requests and Valyu charges per task ($0.10 to $2.50).

Does Linkup meet enterprise compliance requirements?

Yes. Linkup is SOC 2 Type II certified, GDPR compliant, Zero Data Retention for enterprise partners.